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Grenier G, Rochat EC, Muladal R, Jensen H, Knudsen R. Salmon-lice as a potential threat to anadromous Arctic charr populations. J Fish Dis 2023; 46:465-475. [PMID: 36696463 DOI: 10.1111/jfd.13758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Salmon-lice have the potential to change the behaviour and growth of their salmonid host species. Here, the baseline infection levels of salmon-lice of post-smolts (n = 815) and veteran migrants (n = 875) of sea-run Arctic charr (Salvelinus alpinus Linnaeus, 1758) were monitored over two successive years in a sub-Arctic Norwegian fjord without farming of salmonids. All Arctic charr were collected after the sea-migration period from a trap placed in the river, ascending to their overwintering freshwater habitat (Lake Laksvatn). The sea-lice infection showed a stable infection across the 2 years while increasing through the migration period and with the size of the wild sea-run Arctic charr. The prevalence of sea-lice infection was intermediate to high, and the intensities of sea-lice infections observed were generally modest, although some individuals had high infections. The relatively high infection of salmon-lice highlights the potential detrimental effects these parasites can have at both the individual and population level of such endangered sub-Arctic life-history strategies. A comparative study should be performed in fjords with aquaculture activity as focal points for salmon-lice, to investigate the impact farming have on sea-run Arctic charr populations.
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Affiliation(s)
- Gabrielle Grenier
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Eloïse C Rochat
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | | | | | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
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2
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Brabec J, Rochat EC, Knudsen R, Scholz T, Blasco-Costa I. Mining various genomic resources to resolve old alpha-taxonomy questions: A test of the species hypothesis of the Proteocephalus longicollis species complex (Cestoda: Platyhelminthes) from salmonid fishes. Int J Parasitol 2023; 53:197-205. [PMID: 36706803 DOI: 10.1016/j.ijpara.2022.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 01/27/2023]
Abstract
High-throughput sequencing strategies became commonly employed to study non-model parasites, but the corresponding genomes and transcriptomes were seldom mined following the original publication. Similar to the data generated with genome skimming techniques based on shallow-depth shotgun genomes, various genomic and transcriptomic resources can be screened for useful molecular phylogenetic markers traditionally characterised with Sanger sequencing. Here, we provide an example of a strategy using reduced-representation genomic as well as transcriptomic data to obtain broad insights into the molecular diversity of the cestode Proteocephalus longicollis, a common parasite of salmonids distributed throughout the Holarctic region. We extract popular mitochondrial and nuclear ribosomal markers from various genomic resources for hundreds of parasite specimens from multiple European whitefish populations and compare those with Proteocephalus representatives from other species of salmonids and various geographical regions. In contrast with the previous morphology-based assessments, molecular phylogeny reveals a high degree of genetic divergence between Proteocephalus isolates from different salmonids, contrastingly low genetic differentiation within the parasite's populations hosted by the European whitefish (Coregonus lavaretus species complex), and a sister species relationship of Proteocephalus from European whitefish and Proteocephalus percae, a parasite of European perch (Perca fluviatilis). Proteocephalus spp. from North American lake whitefish, brown trout and Arctic charr each formed clearly distinct lineages. These results advance our understanding of the interrelationships of the Proteocephalus-aggregate, a well-recognized clade of Holarctic freshwater fish proteocephalids, and support resurrection of some of the nominal species of Proteocephalus, including Proteocephalus exiguus La Rue, 1911 from North American coregonids and Proteocephalus fallax La Rue, 1911 from European C. lavaretus, reserving Proteocephalus longicollis (Zeder, 1800) exclusively for parasites of Salmo trutta.
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Affiliation(s)
- Jan Brabec
- Department of Invertebrates, Natural History Museum of Geneva, Geneva, Switzerland; Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.
| | - Eloïse C Rochat
- Department of Arctic Biology, The Arctic University of Norway, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic Biology, The Arctic University of Norway, Tromsø, Norway.
| | - Tomáš Scholz
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Isabel Blasco-Costa
- Department of Invertebrates, Natural History Museum of Geneva, Geneva, Switzerland; Department of Arctic Biology, The Arctic University of Norway, Tromsø, Norway
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3
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Henriksen EH, Frainer A, Poulin R, Knudsen R, Amundsen P. Ectoparasites population dynamics are affected by host body size but not host density or water temperature in a 32‐year long time series. OIKOS 2022. [DOI: 10.1111/oik.09328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Eirik H. Henriksen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - André Frainer
- Norwegian Inst. for Nature Research (NINA), Framsenteret Tromsø Norway
| | | | - Rune Knudsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Per‐Arne Amundsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
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Rochat EC, Paterson RA, Blasco‐Costa I, Power M, Adams CE, Greer R, Knudsen R. Temporal stability of polymorphic Arctic charr parasite communities reflects sustained divergent trophic niches. Ecol Evol 2022; 12:e9460. [PMID: 36349257 PMCID: PMC9636502 DOI: 10.1002/ece3.9460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 11/08/2022] Open
Abstract
Polymorphic Arctic charr Salvelinus alpinus populations frequently display distinct differences in habitat use, diet, and parasite communities. Changes to the relative species densities and composition of the wider fish community have the potential to alter the habitat niche of sympatric Arctic charr populations. This study evaluated the temporal stability of the parasite community, diet, and stable isotopes (δ13C, δ15N) of three sympatric Arctic charr morphs (piscivore, benthivore, and planktivore) from Loch Rannoch, Scotland, in relation to changes to the fish community. All Arctic charr morphs displayed distinct differences in parasite communities, diet, and stable isotope signatures over time, despite the establishment of four new trophically transmitted parasite taxa, and increased fish and zooplankton consumption by the piscivorous and planktivore morphs, respectively. Native parasite prevalence also increased in all Arctic charr morphs. Overall, Loch Rannoch polymorphic Arctic charr morph populations have maintained their distinct trophic niches and parasite communities through time despite changes in the fish community. This result indicates that re‐stocking a native fish species has the potential to induce shifts in the parasite community and diet of Arctic charr morphs.
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Affiliation(s)
- Eloïse C. Rochat
- Department of Arctic and Marine Biology UiT The Arctic University of Norway Tromsø Norway
- Natural History Museum of Geneva Geneva Switzerland
| | | | - Isabel Blasco‐Costa
- Department of Arctic and Marine Biology UiT The Arctic University of Norway Tromsø Norway
- Natural History Museum of Geneva Geneva Switzerland
| | - Michael Power
- Department of Biology University of Waterloo Waterloo Canada
| | - Colin E. Adams
- Scottish Centre for Ecology & the Natural Environment University of Glasgow Glasgow UK
| | | | - Rune Knudsen
- Department of Arctic and Marine Biology UiT The Arctic University of Norway Tromsø Norway
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5
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Born-Torrijos A, van Beest GS, Vyhlídalová T, Knudsen R, Kristoffersen R, Amundsen PA, Thieltges DW, Soldánová M. Taxa-specific activity loss and mortality patterns in freshwater trematode cercariae under subarctic conditions. Parasitology 2022; 149:457-468. [PMID: 35331353 PMCID: PMC11010473 DOI: 10.1017/s0031182021002006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/24/2021] [Accepted: 11/02/2021] [Indexed: 11/07/2022]
Abstract
Cercarial activity and survival are crucial traits for the transmission of trematodes. Temperature is particularly important, as faster depletion of limited cercarial energy reserves occurs at high temperatures. Seasonal climate conditions in high latitude regions may be challenging to complete trematode life cycle during the 6-month ice-free period, but temperature effects on the activity and survival of freshwater cercariae have not been previously identified. After experimentally simulating natural subarctic conditions during warmer and colder months (13 and 6°C), a statistical approach identifying changes in the tendency of cercarial activity loss and mortality data was used to detect differences in three trematode genera, represented by four taxa (Diplostomum spp., Apatemon spp., small- and large-sized Plagiorchis spp.). A strong temperature-dependent response was identified in both activity loss and mortality in all taxa, with Diplostomum spp. cercariae showing the most gradual changes compared to other taxa. Furthermore, whilst activity loss and mortality dynamics could not be divided into ‘fish- vs invertebrate-infecting cercariae’ groups, the detected taxa-specific responses in relation to life-history traits indicate the swimming behaviour of cercariae and energy allocation among larvae individuals as the main drivers. Cercariae exploit the short transmission window that allows a stable continuance of trematodes’ life cycles in high-latitude freshwater ecosystems.
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Affiliation(s)
- Ana Born-Torrijos
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005České Budějovice, Czech Republic
| | - Gabrielle S. van Beest
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005České Budějovice, Czech Republic
- Cavanilles Institute for Biodiversity and Evolutionary Biology, Science Park, University of Valencia, P.O. Box 22085, 46071Valencia, Spain
| | - Tereza Vyhlídalová
- Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 37005České Budějovice, Czech Republic
| | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037Tromsø, Norway
| | - Roar Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037Tromsø, Norway
| | - David W. Thieltges
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790, AB Den Burg, Texel, The Netherlands
| | - Miroslava Soldánová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005České Budějovice, Czech Republic
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Soldánová M, Kundid P, Scholz T, Kristoffersen R, Knudsen R. Somatic Dimorphism in Cercariae of a Bird Schistosome. Pathogens 2022; 11:pathogens11030290. [PMID: 35335614 PMCID: PMC8953619 DOI: 10.3390/pathogens11030290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/20/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Phenotypic polymorphism is a commonly observed phenomenon in nature, but extremely rare in free-living stages of parasites. We describe a unique case of somatic polymorphism in conspecific cercariae of the bird schistosome Trichobilharzia sp. “peregra”, in which two morphs, conspicuously different in their size, were released from a single Radix balthica snail. A detailed morphometric analysis that included multiple morphological parameters taken from 105 live and formalin-fixed cercariae isolated from several naturally infected snails provided reliable evidence for a division of all cercariae into two size groups that contained either large or small individuals. Large morph (total body length of 1368 and 1339 μm for live and formalin-fixed samples, respectively) differed significantly nearly in all morphological characteristics compared to small cercariae (total body length of 976 and 898 μm for live and formalin samples, respectively), regardless of the fixation method. Furthermore, we observed that small individuals represent the normal/commonly occurring phenotype in snail populations. The probable causes and consequences of generating an alternative, much larger phenotype in the parasite infrapopulation are discussed in the context of transmission ecology as possible benefits and disadvantages facilitating or preventing the successful completion of the life cycle.
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Affiliation(s)
- Miroslava Soldánová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (P.K.); (T.S.)
- Correspondence:
| | - Petra Kundid
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (P.K.); (T.S.)
- Department of Parasitology, Faculty of Science, University of South Bohemia in České Budějovice, 370 05 České Budějovice, Czech Republic
| | - Tomáš Scholz
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (P.K.); (T.S.)
- Department of Parasitology, Faculty of Science, University of South Bohemia in České Budějovice, 370 05 České Budějovice, Czech Republic
| | - Roar Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037 Tromsø, Norway; (R.K.); (R.K.)
| | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037 Tromsø, Norway; (R.K.); (R.K.)
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7
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Grenier G, Smalås A, Kjær R, Knudsen R. Environmentally Modulated Repeat Evolution of Polymorphic Arctic Charr Life History Traits. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.771309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sympatric Arctic charr, Salvelinus alpinus (L. 1758), morphs have flexible but repeated life history strategies tested across five Norwegian lakes. In several Scandinavian polymorphic Arctic charr populations differentiated by their diet and habitat use, a large littoral omnivorous (LO) morph commonly cooccurs with a smaller profundal spawning (PB/PZ) morph. A third, large piscivorous (PP) morph is also known to occur within a portion of Arctic charr populations in the profundal habitat along with the PB/PZ individuals. Life history traits, such as age at maturity, growth, and diet are known to differ among coexisting morphs. Notably, the PP morph was the longest morph with the oldest age at maturity while the PB/PZ morph showed the shortest lengths overall and youngest age with LO morph being intermediate in both traits. Growth parameters differed across all the morphs. When examining growth within morph groups, the LO morph was found to have different growth across all lakes, while similar reproductive investments and different energy acquisition patterns were seen within the PB/PZ and PP morphs. These results suggest repeat evolution in several life history strategies of reproductively isolated Arctic charr sympatric morphs, notably for the first time in the PP morph, while also highlighting the importance of the local environment in modulating life history traits.
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8
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Eloranta AP, Finstad AG, Sandlund OT, Knudsen R, Kuparinen A, Amundsen PA. Species interactions, environmental gradients and body size shape population niche width. J Anim Ecol 2021; 91:154-169. [PMID: 34657292 DOI: 10.1111/1365-2656.13611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 10/12/2021] [Indexed: 11/29/2022]
Abstract
Competition for shared resources is commonly assumed to restrict population-level niche width of coexisting species. However, the identity and abundance of coexisting species, the prevailing environmental conditions, and the individual body size may shape the effects of interspecific interactions on species' niche width. Here we study the effects of interspecific and intraspecific interactions, lake area and altitude, and fish body size on the trophic niche width and resource use of a generalist predator, the littoral-dwelling large, sparsely rakered morph of European whitefish (Coregonus lavaretus; hereafter LSR whitefish). We use stable isotope, diet and survey fishing data from 14 subarctic lakes along an environmental gradient in northern Norway. The isotopic niche width of LSR whitefish showed a humped-shaped relationship with increasing relative abundance of sympatric competitors, suggesting widest population niche at intermediate intensity of interspecific interactions. The isotopic niche width of LSR whitefish tended to decrease with increasing altitude, suggesting reduced niche in colder, less productive lakes. LSR whitefish typically shifted to a higher trophic position and increased reliance on littoral food resources with increasing body size, although between-lake differences in ontogenetic niche shifts were evident. In most lakes, LSR whitefish relied less on littoral food resources than coexisting fishes and the niche overlap between sympatric competitors was most evident among relatively large individuals (>250 mm). Individual niche variation was highest among >200 mm long LSR whitefish, which likely have escaped the predation window of sympatric predators. We demonstrate that intermediate intensity of interspecific interactions may broaden species' niche width, whereas strong competition for limited resources and high predation risk may suppress niche width in less productive environments. Acknowledging potential humped-shaped relationships between population niche width and interspecific interactions can help us understand species' responses to environmental disturbance (e.g. climate change and species invasions) as well as the driving forces of niche specialization.
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Affiliation(s)
- Antti P Eloranta
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Department of Aquatic Biodiversity, Norwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Anders G Finstad
- Department of Natural History, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology, Trondheim, Norway
| | - Odd Terje Sandlund
- Department of Aquatic Biodiversity, Norwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Anna Kuparinen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
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9
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Macri EM, Culvenor AG, Englund M, Pihl K, Varnum C, Knudsen R, Lohmander LS, Thorlund JB. Importance of patellofemoral and tibiofemoral cartilage lesions on trajectory of self-reported outcomes in patients at high risk of knee OA: 4-6 years follow-up of patients undergoing meniscal surgery. Osteoarthritis Cartilage 2021; 29:1291-1295. [PMID: 34174456 DOI: 10.1016/j.joca.2021.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 06/08/2021] [Accepted: 06/13/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We evaluated whether patient-reported outcome trajectories (i.e., changes over time) differed by intraoperative compartmental cartilage lesion pattern over 4-6 years following arthroscopic meniscal surgery. METHODS In this ancillary study of the Knee Arthroscopy Cohort Southern Denmark cohort, we intraoperatively categorized cartilage lesions as isolated patellofemoral, isolated tibiofemoral, or combined patellofemoral/tibiofemoral. Participants completed the Knee injury and Osteoarthritis Outcome Score (KOOS) pre-operatively, at 3 and 12 months, and at 4-6 years post-operatively and reported overall satisfaction at final follow-up. Our main outcome was KOOS4 (grand mean of four subscale means). We evaluated whether KOOS4 scores changed over time according to cartilage lesion patterns using adjusted mixed linear regression. We also estimated probability of treatment satisfaction using logistic regression. RESULTS Of 630 participants with complete cartilage scores, 280 (44%) were women, mean (standard deviation) age was 49 (13) years, and BMI was 27.3 (4.4) kg/m2. KOOS4 scores at baseline were slightly lower in all lesion groups compared to the no lesion group, yet only the combined group was statistically significantly lower. KOOS4 trajectories were similar across cartilage lesion patterns, but by final follow-up, adjusted mean KOOS4 scores were 6.8 (95% CI 2.2, 11.4) to 9.8 (1.1, 18.5) points lower in groups with cartilage lesions compared to the no lesion group. Probability of patient-reported satisfaction did not differ statistically by group. CONCLUSIONS Though KOOS4 scores were slightly lower in groups with arthroscopically assessed cartilage lesions compared to the no lesion group, trajectories were similar across all groups.
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Affiliation(s)
- E M Macri
- Department of General Practice, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Orthopaedics and Sports Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Family Practice, University of British Columbia, Vancouver, Canada.
| | - A G Culvenor
- La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Bundoora, Australia.
| | - M Englund
- Department of Clinical Sciences Lund, Orthopedics, Clinical Epidemiology Unit, Lund University, Lund, Sweden.
| | - K Pihl
- Department of Clinical Sciences Lund, Orthopedics, Clinical Epidemiology Unit, Lund University, Lund, Sweden.
| | - C Varnum
- Department of Orthopaedic Surgery, Lillebaelt Hospital - Vejle, University Hospital of Southern Denmark and Department of Regional Health Research, University of Southern Denmark, Denmark.
| | - R Knudsen
- Department of Orthopedics and Traumatology, Odense University Hospital, Odense, Denmark.
| | - L S Lohmander
- Department of Clinical Sciences Lund, Orthopedics, Clinical Epidemiology Unit, Lund University, Lund, Sweden.
| | - J B Thorlund
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark; Research Unit for General Practice, Department of Public Health, University of Southern Denmark, Odense, Denmark.
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10
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Prati S, Henriksen EH, Smalås A, Knudsen R, Klemetsen A, Sánchez-Hernández J, Amundsen PA. The effect of inter‐ and intraspecific competition on individual and population niche widths: a four‐decade study on two interacting salmonids. OIKOS 2021. [DOI: 10.1111/oik.08375] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Sebastian Prati
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Eirik Haugstvedt Henriksen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Aslak Smalås
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Rune Knudsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Anders Klemetsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Javier Sánchez-Hernández
- Depto de Biología, Geología, Física y Química Inorgánica, Univ. Rey Juan Carlos, Móstoles Madrid Spain
| | - Per-Arne Amundsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
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11
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Born-Torrijos A, Paterson RA, van Beest GS, Vyhlídalová T, Henriksen EH, Knudsen R, Kristoffersen R, Amundsen PA, Soldánová M. Cercarial behaviour alters the consumer functional response of three-spined sticklebacks. J Anim Ecol 2021; 90:978-988. [PMID: 33481253 DOI: 10.1111/1365-2656.13427] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 01/04/2021] [Indexed: 01/16/2023]
Abstract
Free-living parasite life stages may contribute substantially to ecosystem biomass and thus represent a significant source of energy flow when consumed by non-host organisms. However, ambient temperature and the predator's own infection status may modulate consumption rates towards parasite prey. We investigated the combined effects of temperature and predator infection status on the consumer functional response of three-spined sticklebacks towards the free-living cercariae stages of two common freshwater trematode parasites (Plagiorchis spp., Trichobilharzia franki). Our results revealed genera-specific functional responses and consumption rates towards each parasite prey: Type II for Plagiorchis spp. and Type III for T. franki, with an overall higher consumption rate on T. franki. Elevated temperature (13°C) increased the consumption rate on Plagiorchis spp. prey for sticklebacks with mild cestode infections (<5% fish body weight) only. High consumption of cercarial prey by sticklebacks may impact parasite population dynamics by severely reducing or even functionally eliminating free-living parasite life stages from the environment. This supports the potential role of fish as biocontrol agents for cercariae with similar dispersion strategies, in instances where functional response relationships have been established. Our study demonstrates how parasite consumption by non-host organisms may be shaped by traits inherent to parasite transmission and dispersal, and emphasises the need to consider free-living parasite life stages as integral energy resources in aquatic food webs.
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Affiliation(s)
- Ana Born-Torrijos
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Rachel A Paterson
- School of Biosciences, Cardiff University, Cardiff, UK.,The Norwegian Institute for Nature Research, Trondheim, Norway
| | - Gabrielle S van Beest
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Cavanilles Institute for Biodiversity and Evolutionary Biology, Science Park, University of Valencia, Valencia, Spain
| | - Tereza Vyhlídalová
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| | - Eirik H Henriksen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Roar Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Miroslava Soldánová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
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Shaw JC, Henriksen EH, Knudsen R, Kuhn JA, Kuris AM, Lafferty KD, Siwertsson A, Soldánová M, Amundsen P. High parasite diversity in the amphipod Gammarus lacustris in a subarctic lake. Ecol Evol 2020; 10:12385-12394. [PMID: 33209296 PMCID: PMC7663964 DOI: 10.1002/ece3.6869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 02/02/2023] Open
Abstract
Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population, precluding a more dynamic understanding of the food web. We set out to identify and quantify the parasite community of Gammarus lacustris to understand the contributions of the amphipod and its parasites to the Takvatn food web. We identified seven parasite taxa: a direct life cycle gregarine, Rotundula sp., and larval stages of two digenean trematode genera, two cestodes, one nematode, and one acanthocephalan. The larval parasites use either birds or fishes as final hosts. Bird parasites predominated, with trematode Plagiorchis sp. having the highest prevalence (69%) and mean abundance (2.7). Fish parasites were also common, including trematodes Crepidostomum spp., nematode Cystidicola farionis, and cestode Cyathocephalus truncatus (prevalences 13, 6, and 3%, respectively). Five parasites depend entirely on G. lacustris to complete their life cycle. At least 11.4% of the overall parasite diversity in the lake was dependent on G. lacustris, and 16% of the helminth diversity required or used the amphipod in their life cycles. These dependencies reveal that in addition to being a key prey item in subarctic lakes, G. lacustris is also an important host for maintaining parasite diversity in such ecosystems.
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Affiliation(s)
- Jenny C. Shaw
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCAUSA
| | - Eirik H. Henriksen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Rune Knudsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Jesper A. Kuhn
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Armand M. Kuris
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCAUSA
- Department of Ecology, Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCAUSA
| | - Kevin D. Lafferty
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCAUSA
- Western Ecological ResearchU.S. Geological SurveySanta BarbaraCAUSA
| | - Anna Siwertsson
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
- Institute of Marine ResearchEcosystem Processes Research GroupTromsøNorway
| | - Miroslava Soldánová
- Institute of Parasitology, Biology CentreCzech Academy of SciencesČeské BudějoviceCzech Republic
| | - Per‐Arne Amundsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
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Crotti M, Adams CE, Etheridge EC, Bean CW, Gowans ARD, Knudsen R, Lyle AA, Maitland PS, Winfield IJ, Elmer KR, Præbel K. Geographic hierarchical population genetic structuring in British European whitefish (Coregonus lavaretus) and its implications for conservation. CONSERV GENET 2020. [DOI: 10.1007/s10592-020-01298-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractThe European whitefish Coregonus lavaretus complex represents one of the most diverse radiations within salmonids, with extreme morphological and genetic differentiation across its range. Such variation has led to the assignment of many populations to separate species. In Great Britain, the seven native populations of C. lavaretus (two in Scotland, four in England, one in Wales) were previously classified into three species, and recent taxonomic revision resurrected the previous nomenclature. Here we used a dataset of 15 microsatellites to: (1) investigate the genetic diversity of British populations, (2) assess the level of population structure and the relationships between British populations. Genetic diversity was highest in Welsh (HO = 0.50, AR = 5.29), intermediate in English (HO = 0.41–0.50, AR = 2.83–3.88), and lowest in Scottish populations (HO = 0.28–0.35, AR = 2.56–3.04). Population structure analyses indicated high genetic differentiation (global FST = 0.388) between all populations but for the two Scottish populations (FST = 0.063) and two English populations (FST = 0.038). Principal component analysis and molecular ANOVA revealed separation between Scottish, English, and Welsh populations, with the Scottish populations being the most diverged. We argue that the data presented here are not sufficient to support a separation of the British European whitefish populations into three separate species, but support the delineation of different ESUs for these populations.
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14
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Prati S, Henriksen EH, Knudsen R, Amundsen PA. Impacts of ontogenetic dietary shifts on the food-transmitted intestinal parasite communities of two lake salmonids. Int J Parasitol Parasites Wildl 2020; 12:155-164. [PMID: 32577375 PMCID: PMC7300134 DOI: 10.1016/j.ijppaw.2020.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 11/06/2022]
Abstract
Ontogenetic dietary shifts are common in fish and often impact trophically transmitted parasite communities. How parasite species composition and relative abundances change among size classes, and at what rate these changes occur, is rarely examined. Hosts with a broad trophic niche are potentially exposed to a large variety of parasite species. The degree of ontogenetic changes in parasite species composition versus changes in parasite abundance should suggestively differ between thropically generalist and specialist host species. In the present study, we explore ontogenetic dietary shifts and their impact on species composition and relative abundance of intestinal parasites in two sympatric salmonid fish species, Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) caught in the littoral habitat of a subarctic lake. Our results highlight a close interplay between ontogenetic dietary niche shifts and alterations in the acquisition of trophically transmitted parasites, leading to host-specific differences in the component community of parasites. Ontogenetic changes in the intestinal parasite community related to dietary niche shifts were distinct but less pronounced in Arctic charr than in brown trout due to a broader and more consistent dietary niche of the former and an ontogenetic shift toward piscivory in the latter. At the component community level, changes in parasite assemblages of both host species were driven by a faster increase in the heterogeneity of parasite relative abundance than in the compositional heterogeneity, a pattern that partly may be related to a rather species-poor parasite community of this subarctic study system. Separating compositional heterogeneity from heterogeneity in relative parasite abundance is important to understand how size-dependent variability shapes parasite communities of host populations. Ontogenetic dietary niche shifts generated host-specific differences in the component community of parasites. Ontogenetic changes in the intestinal parasite community were less pronounced in Arctic charr than in brown trout. Heterogeneity of parasite relative abundance increased faster than the compositional heterogeneity.
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Affiliation(s)
- Sebastian Prati
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
| | - Eirik Haugstvedt Henriksen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
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15
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Prati S, Henriksen EH, Knudsen R, Amundsen P. Seasonal dietary shifts enhance parasite transmission to lake salmonids during ice cover. Ecol Evol 2020; 10:4031-4043. [PMID: 32489629 PMCID: PMC7244800 DOI: 10.1002/ece3.6173] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/17/2020] [Accepted: 02/19/2020] [Indexed: 12/19/2022] Open
Abstract
Changes in abiotic and biotic factors between seasons in subarctic lake systems are often profound, potentially affecting the community structure and population dynamics of parasites over the annual cycle. However, few winter studies exist and interactions between fish hosts and their parasites are typically confined to snapshot studies restricted to the summer season whereas host-parasite dynamics during the ice-covered period rarely have been explored. The present study addresses seasonal patterns in the infections of intestinal parasites and their association with the diet of sympatric living Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in Lake Takvatn, a subarctic lake in northern Norway. In total, 354 Arctic charr and 203 brown trout were sampled from the littoral habitat between June 2017 and May 2018. Six trophically transmitted intestinal parasite taxa were identified and quantified, and their seasonal variations were contrasted with dietary information from both stomachs and intestines of the fish. The winter period proved to be an important transmission window for parasites, with increased prevalence and intensity of amphipod-transmitted parasites in Arctic charr and parasites transmitted through fish prey in brown trout. In Arctic charr, seasonal patterns in parasite infections resulted mainly from temporal changes in diet toward amphipods, whereas host body size and the utilization of fish prey were the main drivers in brown trout. The overall dynamics in the community structure of parasites chiefly mirrored the seasonal dietary shifts of their fish hosts.
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Affiliation(s)
- Sebastian Prati
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Eirik H. Henriksen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Rune Knudsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Per‐Arne Amundsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
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16
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Davidsen JG, Power M, Knudsen R, Sjursen AD, Kjaerstad G, Rønning L, Arnekleiv JV. Marine trophic niche use and life history diversity among Arctic charr Salvelinus alpinus in southwestern Greenland. J Fish Biol 2020; 96:681-692. [PMID: 31970772 DOI: 10.1111/jfb.14261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
Life history strategies and potential marine niche use of Arctic charr Salvelinus alpinus (n = 237, 84-652 mm, total body length, LT ) were determined during the ice-free season (2012) at three different watercourses in south-western Greenland. All Arctic charr were collected from freshwater habitats. Based on stable isotopes of δ34 S, the Arctic charr were categorized as either marine- or freshwater-dependent feeders. The use of time-integrated trophic tracers (stable isotopes of δ13 C, δ15 N, δ34 S) suggested that several trophic groups of Arctic charr operate alongside within each fjord system. The groups suggested were one group that specialized in the marine habitat, in addition to two freshwater resident morphs (small-sized resident and/or large-growing cannibalistic individuals). Stomach contents consisted entirely of freshwater and terrestrial prey (i.e., insects), indicating that marine-dependent feeders also fed in freshwater habitats after return from their marine migration. Growth and maturity patterns further supported variable life history strategies within each watercourse. The life history strategy patterns and marine trophic niche use were consistent across the watercourses along several hundred kilometres of coastline. This study represents the first ecological baseline for partially anadromous populations of Greenland Arctic charr.
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Affiliation(s)
- Jan G Davidsen
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Michael Power
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Rune Knudsen
- Department of Arctic and Marine Biology, The Arctic University of Norway, Tromsø, Norway
| | - Aslak D Sjursen
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gaute Kjaerstad
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lars Rønning
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jo V Arnekleiv
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
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17
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Skúlason S, Parsons KJ, Svanbäck R, Räsänen K, Ferguson MM, Adams CE, Amundsen P, Bartels P, Bean CW, Boughman JW, Englund G, Guðbrandsson J, Hooker OE, Hudson AG, Kahilainen KK, Knudsen R, Kristjánsson BK, Leblanc CA, Jónsson Z, Öhlund G, Smith C, Snorrason SS. A way forward with eco evo devo: an extended theory of resource polymorphism with postglacial fishes as model systems. Biol Rev Camb Philos Soc 2019; 94:1786-1808. [PMID: 31215138 PMCID: PMC6852119 DOI: 10.1111/brv.12534] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/12/2019] [Accepted: 05/20/2019] [Indexed: 12/16/2022]
Abstract
A major goal of evolutionary science is to understand how biological diversity is generated and altered. Despite considerable advances, we still have limited insight into how phenotypic variation arises and is sorted by natural selection. Here we argue that an integrated view, which merges ecology, evolution and developmental biology (eco evo devo) on an equal footing, is needed to understand the multifaceted role of the environment in simultaneously determining the development of the phenotype and the nature of the selective environment, and how organisms in turn affect the environment through eco evo and eco devo feedbacks. To illustrate the usefulness of an integrated eco evo devo perspective, we connect it with the theory of resource polymorphism (i.e. the phenotypic and genetic diversification that occurs in response to variation in available resources). In so doing, we highlight fishes from recently glaciated freshwater systems as exceptionally well-suited model systems for testing predictions of an eco evo devo framework in studies of diversification. Studies on these fishes show that intraspecific diversity can evolve rapidly, and that this process is jointly facilitated by (i) the availability of diverse environments promoting divergent natural selection; (ii) dynamic developmental processes sensitive to environmental and genetic signals; and (iii) eco evo and eco devo feedbacks influencing the selective and developmental environments of the phenotype. We highlight empirical examples and present a conceptual model for the generation of resource polymorphism - emphasizing eco evo devo, and identify current gaps in knowledge.
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Affiliation(s)
- Skúli Skúlason
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókur, 551Iceland
- Icelandic Museum of Natural History, Brynjólfsgata 5ReykjavíkIS‐107Iceland
| | - Kevin J. Parsons
- Institute of Biodiversity, Animal Health & Comparative MedicineUniversity of GlasgowGlasgow, G12 8QQU.K.
| | - Richard Svanbäck
- Animal Ecology, Department of Ecology and Genetics, Science for Life LaboratoryUppsala University, Norbyvägen 18DUppsala, SE‐752 36Sweden
| | - Katja Räsänen
- Department of Aquatic EcologyEAWAG, Swiss Federal Institute of Aquatic Science and Technology, and Institute of Integrative Biology, ETH‐Zurich, Ueberlandstrasse 133CH‐8600DübendorfSwitzerland
| | - Moira M. Ferguson
- Department of Integrative BiologyUniversity of GuelphGuelph, Ontario N1G 2W1Canada
| | - Colin E. Adams
- Scottish Centre for Ecology and the Natural Environment, IBAHCMUniversity of GlasgowGlasgow G12 8QQU.K.
| | - Per‐Arne Amundsen
- Freshwater Ecology Group, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and EconomicsUniversity of TromsöTromsö, N‐9037Norway
| | - Pia Bartels
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Colin W. Bean
- Scottish Natural Heritage, Caspian House, Mariner Court, Clydebank Business ParkClydebank, G81 2NRU.K.
| | - Janette W. Boughman
- Department of Integrative BiologyMichigan State UniversityEast Lansing, MI 48824U.S.A.
| | - Göran Englund
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Jóhannes Guðbrandsson
- Institute of Life and Environmental SciencesUniversity of IcelandReykjavik, 101Iceland
| | | | - Alan G. Hudson
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Kimmo K. Kahilainen
- Inland Norway University of Applied Sciences, Department of Forestry and Wildlife Management, Campus Evenstad, Anne Evenstadvei 80Koppang, NO‐2480Norway
| | - Rune Knudsen
- Freshwater Ecology Group, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and EconomicsUniversity of TromsöTromsö, N‐9037Norway
| | | | - Camille A‐L. Leblanc
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókur, 551Iceland
| | - Zophonías Jónsson
- Institute of Life and Environmental SciencesUniversity of IcelandReykjavik, 101Iceland
| | - Gunnar Öhlund
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Carl Smith
- School of BiologyUniversity of St Andrews, St. AndrewsFife, KY16 9AJU.K.
| | - Sigurður S. Snorrason
- Institute of Life and Environmental SciencesUniversity of IcelandReykjavik, 101Iceland
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18
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Henriksen EH, Frainer A, Knudsen R, Kristoffersen R, Kuris AM, Lafferty KD, Amundsen P. Fish culling reduces tapeworm burden in Arctic charr by increasing parasite mortality rather than by reducing density‐dependent transmission. J Appl Ecol 2019. [DOI: 10.1111/1365-2664.13369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Eirik H. Henriksen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of Norway Tromsø Norway
| | - André Frainer
- Norwegian College of Fishery ScienceFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of Norway Tromsø Norway
- Norwegian Institute for Nature Research (NINA) Tromsø Norway
| | - Rune Knudsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of Norway Tromsø Norway
| | - Roar Kristoffersen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of Norway Tromsø Norway
| | - Armand M. Kuris
- Department of Ecology, Evolution and Marine BiologyMarine Science InstituteUC Santa Barbara Santa Barbara California
| | - Kevin D. Lafferty
- U.S. Geological SurveyWestern Ecological Research CenterMarine Science InstituteUC Santa Barbara Santa Barbara California
| | - Per‐Arne Amundsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of Norway Tromsø Norway
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19
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Hayden B, Harrod C, Thomas SM, Eloranta AP, Myllykangas J, Siwertsson A, Præbel K, Knudsen R, Amundsen P, Kahilainen KK. From clear lakes to murky waters – tracing the functional response of high‐latitude lake communities to concurrent ‘greening’ and ‘browning’. Ecol Lett 2019; 22:807-816. [DOI: 10.1111/ele.13238] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/21/2018] [Accepted: 01/20/2019] [Indexed: 12/24/2022]
Affiliation(s)
- B. Hayden
- Department of Biology Canadian Rivers Institute University of New Brunswick New Brunswick Canada
- Kilpisjärvi Biological Station University of Helsinki Helsinki Finland
| | - C. Harrod
- Instituto de Ciencias Naturales Alexander von Humboldt Universidad de Antofagasta Antofagasta Chile
- Núcleo Milenio INVASAL Concepción Chile
| | - S. M. Thomas
- EAWAG Swiss Federal Institute of Aquatic Science and Technology Center for Ecology, Evolution and Biogeochemistry Kastanienbaum Switzerland
| | - A. P. Eloranta
- Department of Aquatic Ecology Norwegian Institute for Nature Research (NINA) Trondheim Norway
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - J.‐P. Myllykangas
- Kilpisjärvi Biological Station University of Helsinki Helsinki Finland
| | - A. Siwertsson
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - K. Præbel
- Norwegian College of Fishery Science Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - R. Knudsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - P.‐A. Amundsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - K. K. Kahilainen
- Kilpisjärvi Biological Station University of Helsinki Helsinki Finland
- Department of Forestry and Wildlife Management Inland Norway University of Applied Sciences Campus Evenstad Norway
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20
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Frainer A, McKie BG, Amundsen PA, Knudsen R, Lafferty KD. Parasitism and the Biodiversity-Functioning Relationship. Trends Ecol Evol 2018; 33:260-268. [PMID: 29456188 DOI: 10.1016/j.tree.2018.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 01/13/2023]
Abstract
Species interactions can influence ecosystem functioning by enhancing or suppressing the activities of species that drive ecosystem processes, or by causing changes in biodiversity. However, one important class of species interactions - parasitism - has been little considered in biodiversity and ecosystem functioning (BD-EF) research. Parasites might increase or decrease ecosystem processes by reducing host abundance. Parasites could also increase trait diversity by suppressing dominant species or by increasing within-host trait diversity. These different mechanisms by which parasites might affect ecosystem function pose challenges in predicting their net effects. Nonetheless, given the ubiquity of parasites, we propose that parasite-host interactions should be incorporated into the BD-EF framework.
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Affiliation(s)
- André Frainer
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, 9037 Norway; Norwegian College of Fishery Science, UiT The Arctic University of Norway, Tromsø, 9037 Norway.
| | - Brendan G McKie
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, SE 750 07 Sweden
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, 9037 Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, 9037 Norway
| | - Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
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21
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Padrós F, Knudsen R, Blasco-Costa I. Histopathological characterisation of retinal lesions associated to Diplostomum species (Platyhelminthes: Trematoda) infection in polymorphic Arctic charr Salvelinus alpinus. Int J Parasitol Parasites Wildl 2018; 7:68-74. [PMID: 29988817 PMCID: PMC6032039 DOI: 10.1016/j.ijppaw.2018.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/12/2018] [Accepted: 01/20/2018] [Indexed: 01/01/2023]
Abstract
The eye represents an immune privileged organ where parasites can escape host reactions. This study provides the first systematic evidence of the pathology associated with Diplostomum sp. infection in the eye retina of fish (i.e. Arctic charr). Histological sections showed that the trematodes caused mechanical disengagement between the retinal pigmentary epithelium and the neurosensory retina, with damaged cones and rods in the outer segment and epithelium reduced to a single layer of pigmentary cells. The metacercariae were “floating” in possibly fluid-filled vesicles together with several round cells, mostly located in the anterio-dorsal and anterio-ventral areas of the eye near the iris. The round cells may indicate internal retinal damage repair mechanisms, without connections to the general immune system. Metacercariae intestines contained pigmented cellular debris indicating that they feed on retinal epithelium. These retinal lesions may have similar vision effects as focal retinal detachment in vertebrates. Diplostomum metacercaria alters fish visual acuity but may in a lesser degree lead to a severe or total visual impairment because of repairing mechanisms. The pathology in the retina seems thereby to be dependent on fish size, age and dose. Histological description of the distribution of Diplostomum in the eye of Arctic charr Salvelinus alpinus. Metacercaria specifically located in spaces formed between the retinal pigmentary epithelium and the neurosensory retina. Lesions display closer similarities with those observed in retinal detachment in other species. Changes in the frequency and distribution of the lesions between morphs are suggested.
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Affiliation(s)
- F Padrós
- Fish Diseases Diagnostic Service, BAVE, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
| | - R Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Langnes, P.O. Box 6050, 9037 Tromsø, Norway
| | - I Blasco-Costa
- Natural History Museum of Geneva, PO Box 6434, CH-1211 Geneva 6, Switzerland
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22
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Knudsen R, Henriksen EH, Gjelland KØ, Hansen H, Hendrichsen DK, Kristoffersen R, Olstad K. Are hybrids between Atlantic salmon and brown trout suitable long-term hosts of Gyrodactylus salaris during winter? J Fish Dis 2017; 40:1299-1307. [PMID: 28105680 DOI: 10.1111/jfd.12602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
The monogenean parasite Gyrodactylus salaris poses serious threats to many Atlantic salmon populations and presents many conservation and management questions/foci and challenges. It is therefore critical to identify potential vectors for infection. To test whether hybrids of native Atlantic salmon (Salmo salar) × brown trout (Salmo trutta) are suitable as reservoir hosts for G. salaris during winter, infected hybrid parr were released into a natural subarctic brook in the autumn. Six months later, 23.9% of the pit-tagged fish were recaptured. During the experimental period, the hybrids had a sixfold increase in mean intensity of G. salaris, while the prevalence decreased from 81% to 35%. There was high interindividual hybrid variability in susceptibility to infections. The maximum infrapopulation growth rate (0.018 day-1 ) of G. salaris throughout the winter was comparable to earlier laboratory experiments at similar temperatures. The results confirm that infrapopulations of G. salaris may reproduce on a hybrid population for several generations at low water temperatures (~1 °C). Wild salmon-trout hybrids are undoubtedly susceptible to G. salaris and represent an important reservoir host for the parasite independent of other co-occurring susceptible hosts. Consequently, these hybrids may pose a serious risk for G. salaris transmission to nearby, uninfected rivers by migratory individuals.
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Affiliation(s)
- R Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - E H Henriksen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - K Ø Gjelland
- Fram Centre, Norwegian Institute for Nature Research, Tromsø, Norway
| | - H Hansen
- Norwegian Veterinary Institute, Oslo, Norway
| | | | - R Kristoffersen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - K Olstad
- Norwegian Institute for Nature Research, Lillehammer, Norway
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Simonsen MK, Siwertsson A, Adams CE, Amundsen PA, Præbel K, Knudsen R. Allometric trajectories of body and head morphology in three sympatric Arctic charr ( Salvelinus alpinus (L.)) morphs. Ecol Evol 2017; 7:7277-7289. [PMID: 28944016 PMCID: PMC5606865 DOI: 10.1002/ece3.3224] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 05/26/2017] [Accepted: 06/01/2017] [Indexed: 01/01/2023] Open
Abstract
A study of body and head development in three sympatric reproductively isolated Arctic charr (Salvelinus alpinus (L.)) morphs from a subarctic lake (Skogsfjordvatn, northern Norway) revealed allometric trajectories that resulted in morphological differences. The three morphs were ecologically assigned to a littoral omnivore, a profundal benthivore and a profundal piscivore, and this was confirmed by genetic analyses (microsatellites). Principal component analysis was used to identify the variables responsible for most of the morphological variation of the body and head shape. The littoral omnivore and the profundal piscivore morph had convergent allometric trajectories for the most important head shape variables, developing bigger mouths and relatively smaller eyes with increasing head size. The two profundal morphs shared common trajectories for the variables explaining most of the body and head shape variation, namely head size relative to body size, placement of the dorsal and pelvic fins, eye size and mouth size. In contrast, the littoral omnivore and the profundal benthivore morphs were not on common allometric trajectories for any of the examined variables. The findings suggest that different selective pressures could have been working on traits related to their trophic niche such as habitat and diet utilization of the three morphs, with the two profundal morphs experiencing almost identical environmental conditions.
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Affiliation(s)
- Marianne Knutsdotter Simonsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Anna Siwertsson
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Colin Ean Adams
- Scottish Centre for Ecology and the Natural Environment IBAHCM, University of Glasgow Glasgow UK
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Kim Præbel
- Faculty of Biosciences, Fisheries and Economics The Norwegian College of Fishery Science UiT The Arctic University of Norway Tromsø Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology Faculty of Biosciences, Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway
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Kuhn JA, Knudsen R, Kristoffersen R, Amundsen PA. A simplified method to estimate Diphyllobothrium spp. infection in salmonids. J Fish Dis 2017; 40:863-871. [PMID: 27734504 DOI: 10.1111/jfd.12566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/07/2016] [Accepted: 09/07/2016] [Indexed: 06/06/2023]
Abstract
Some fish parasites constitute severe management problems as they may cause mortality of their fish host or are important zoonoses of humans. Parasite assessments are therefore critical to keep track of infections. If conventional sampling techniques can be simplified, parasite assessments might be easier to obtain, less time-consuming and more extensive. In this study, we compare the assessed number of Diphyllobothrium spp. cysts (CYST) with the counted number of Diphyllobothrium spp. plerocercoid larvae recovered using a conventional digestive technique (LARV). The aim was to determine the potential of using CYST as a simplified methodology for assessing Diphyllobothrium spp. infection in salmonids. In total, 365 brown trout and 424 Arctic charr were sampled from nine lakes in subarctic Norway. Strong correlation, significant linear relationship and large amount of explained variation were found between log10 CYST and log10 LARV in both fish species. The method had a slight, but not significant tendency to work better in charr compared to trout. In addition, absolute difference between CYST and LARV increased at parasite intensities >100 indicating that the method has reduced functionality when estimating parasite intensity in heavily infected salmonid populations. However, overall, using this simplified and less time-consuming methodology, a good indication of Diphyllobothrium spp. intensity, abundance and prevalence was obtained. We suggest that this method provides a sound proxy of the Diphyllobothrium spp. burden and have the potential to be used in parasite assessment during fish monitoring and fisheries management surveys, particularly if the time and resources for detailed parasite studies are not available.
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Affiliation(s)
- J A Kuhn
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - R Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - R Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - P-A Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
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25
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Smalås A, Amundsen PA, Knudsen R. The trade-off between fecundity and egg size in a polymorphic population of Arctic charr ( Salvelinus alpinus (L.)) in Skogsfjordvatn, subarctic Norway. Ecol Evol 2017; 7:2018-2024. [PMID: 28405269 PMCID: PMC5383491 DOI: 10.1002/ece3.2669] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 10/27/2016] [Accepted: 11/08/2016] [Indexed: 11/23/2022] Open
Abstract
Reproductive traits differ between intralacustrine Arctic charr morphs. Here, we examine three sympatric lacustrine Arctic charr morphs with respect to fecundity, egg size and spawning time/site to assess reproductive investments and trade‐offs, and possible fitness consequences. The littoral omnivore morph (LO‐morph) utilizes the upper water for feeding and reproduction and spawn early in October. The large profundal piscivore morph (PP‐morph) and the small profundal benthivore morph (PB‐morph) utilize the profundal habitat for feeding and reproduction and spawn in December and November, respectively. Females from all morphs were sampled for fecundity and egg‐size analysis. There were large differences between the morphs. The PB‐morph had the lowest fecundity (mean = 45, SD = 13) and smallest egg size (mean = 3.2 mm, SD = 0.32 mm). In contrast, the PP‐morph had the highest fecundity (mean = 859.5, SD = 462) and the largest egg size (mean = 4.5 mm, SD = 0.46 mm), whereas the LO‐morph had intermediate fecundity (mean = 580, SD = 225) and egg size (mean = 4.3, SD = 0.24 mm). Fecundity increased with increasing body size within each morph. This was not the case for egg size, which was independent of body sizes within morph. Different adaptations to feeding and habitat utilization have apparently led to a difference in the trade‐off between fecundity and egg size among the three different morphs.
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Affiliation(s)
- Aslak Smalås
- Department of Arctic and Marine Biology UiT-the Arctic University of Norway Tromsø Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology UiT-the Arctic University of Norway Tromsø Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology UiT-the Arctic University of Norway Tromsø Norway
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26
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Busarova OY, Knudsen R, Markevich GN. [PARASITES FAUNA OF THE LAKE KRONOTSKOE CHARRS (SALVELINUS), KAMCHATKA]. Parazitologiia 2016; 50:409-425. [PMID: 29215222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The new data on the parasites fauna of the Lake Kronotskoe sympatric charr forms (genus Salvelinus (Nilsson) Richardson, 1836) is presented. Parasites fauna of Bigmouth and Smallmouth charr forms are described for the first time. The information about Longhead charr, Nosed charr and White charr parasites is added. 29 species of parasites from 9 classes were found: Oligohymenophorea, Myxosporea, Monogenea, Trematoda, Cestoda, Nematoda, Acantocephala, Crustacea and Hirudinea. Longhead charr was the most intensively infected by Proteocephalus longicollis (Zeder, 1800) (abundance 306.0) and Neoechinorhynchus salmonis Ching, 1984 (abundance 230.0). White charr was mostly infected by Crepidostomum Braun, 1900 (abundance 242.2) and P. longicollis (abundance 183.4). Nosed charr group that feed on gammarids was infected mostly by Crepidostomum spp. (abundance 3461.3), Cyathocephalus truncatus (Pallas, 1781) (abundance 179.9) and Cystidicola farionis Fisher, 1798 (abundance 169.0); while Chironomidae consumers group was infected mostly by Diplostomum Nordmann, 1832 (abundance 62.3) and Phyllodistomum umblae (Fabricius, 1780) (abundance 27.3). Bigmouth charr was infected mostly by P. longicollis (abundance 17.0) and Eubolhrium salvelini Schrank, 1790 (abundance 11.0), Smallmouth charr form — by P. longicollis (abundance 67.0) and Diplostomum sp. (abundance 64.2). Sympatric flock of charrs form the Lake Kronotskoe (Kamchatka) is the most polymorphic for the genus Salvelinus in Eurasia. According to the parasitological analysis this flock consists six ecological forms.
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Kuhn JA, Frainer A, Knudsen R, Kristoffersen R, Amundsen PA. Effects of fish species composition on Diphyllobothrium spp. infections in brown trout - is three-spined stickleback a key species? J Fish Dis 2016; 39:1313-1323. [PMID: 27111407 DOI: 10.1111/jfd.12467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 12/26/2015] [Accepted: 12/27/2015] [Indexed: 06/05/2023]
Abstract
Subarctic populations of brown trout (Salmo trutta) are often heavily infected with cestodes of the genus Diphyllobothrium, assumedly because of their piscivorous behaviour. This study explores possible associations between availability of fish prey and Diphyllobothrium spp. infections in lacustrine trout populations. Trout in (i) allopatry (group T); (ii) sympatry with Arctic charr (Salvelinus alpinus) (group TC); and (iii) sympatry with charr and three-spined stickleback (Gasterosteus aculeatus) (group TCS) were contrasted. Mean abundance and intensity of Diphyllobothrium spp. were higher in group TCS compared to groups TC and T. Prevalence, however, was similarly higher in groups TCS and TC compared to group T. Zero-altered negative binomial modelling identified the lowest probability of infection in group T and similar probabilities of infection in groups TC and TCS, whereas the highest intensity was predicted in group TCS. The most infected trout were from the group co-occurring with stickleback (TCS), possibly due to a higher availability of fish prey. In conclusion, our study demonstrates elevated Diphyllobothrium spp. infections in lacustrine trout populations where fish prey are available and suggests that highly available and easily caught stickleback prey may play a key role in the transmission of Diphyllobothrium spp. parasite larvae.
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Affiliation(s)
- J A Kuhn
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway.
| | - A Frainer
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - R Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - R Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - P-A Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
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28
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Adams CE, Bean CW, Dodd JA, Down A, Etheridge EC, Gowans ARD, Hooker O, Knudsen R, Lyle AA, Winfield IJ, Præbel K. Inter and intra-population phenotypic and genotypic structuring in the European whitefish Coregonus lavaretus, a rare freshwater fish in Scotland. J Fish Biol 2016; 88:580-594. [PMID: 26748995 DOI: 10.1111/jfb.12855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
This study revealed between-lake genetic structuring between Coregonus lavaretus collected from the only two native populations of this species in Scotland, U.K. (Lochs Eck and Lomond) evidenced by the existence of private alleles (12 in Lomond and four in Eck) and significant genetic differentiation (FST = 0·056) across 10 microsatellite markers. Juvenile C. lavaretus originating from eggs collected from the two lakes and reared in a common-garden experiment showed clear phenotypic differences in trophic morphology (i.e. head and body shape) between these populations indicating that these characteristics were, at least partly, inherited. Microsatellite analysis of adults collected from different geographic regions within Loch Lomond revealed detectable and statistically significant but relatively weak genetic structuring (FST = 0·001-0·024) and evidence of private alleles related to the basin structure of the lake. Within-lake genetic divergence patterns suggest three possibilities for this observed pattern: (1) differential selection pressures causing divergence into separate gene pools, (2) a collapse of two formerly divergent gene pools and (3) a stable state maintained by balancing selection forces resulting from spatial variation in selection and lake heterogeneity. Small estimates of effective population sizes for the populations in both lakes suggest that the capacity of both populations to adapt to future environmental change may be limited.
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Affiliation(s)
- C E Adams
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - C W Bean
- Scottish Natural Heritage, Caspian House, Clydebank Business Park, Clydebank, Glasgow G81 2NR, U.K
| | - J A Dodd
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - A Down
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - E C Etheridge
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - A R D Gowans
- Environment Agency, Ghyll Mount, Gillan Way, Penrith 40 Business Park, Penrith, Cumbria CA11 9BP, U.K
| | - O Hooker
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - R Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - A A Lyle
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - I J Winfield
- Lake Ecosystems Group, Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, U.K
| | - K Præbel
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
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Skoglund S, Siwertsson A, Amundsen PA, Knudsen R. Morphological divergence between three Arctic charr morphs - the significance of the deep-water environment. Ecol Evol 2015; 5:3114-29. [PMID: 26357540 PMCID: PMC4559054 DOI: 10.1002/ece3.1573] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 11/17/2022] Open
Abstract
Morphological divergence was evident among three sympatric morphs of Arctic charr (Salvelinus alpinus (L.)) that are ecologically diverged along the shallow-, deep-water resource axis in a subarctic postglacial lake (Norway). The two deep-water (profundal) spawning morphs, a benthivore (PB-morph) and a piscivore (PP-morph), have evolved under identical abiotic conditions with constant low light and temperature levels in their deep-water habitat, and were morphologically most similar. However, they differed in important head traits (e.g., eye and mouth size) related to their different diet specializations. The small-sized PB-morph had a paedomorphic appearance with a blunt head shape, large eyes, and a deep body shape adapted to their profundal lifestyle feeding on submerged benthos from soft, deep-water sediments. The PP-morph had a robust head, large mouth with numerous teeth, and an elongated body shape strongly related to their piscivorous behavior. The littoral spawning omnivore morph (LO-morph) predominantly utilizes the shallow benthic–pelagic habitat and food resources. Compared to the deep-water morphs, the LO-morph had smaller head relative to body size. The LO-morph exhibited traits typical for both shallow-water benthic feeding (e.g., large body depths and small eyes) and planktivorous feeding in the pelagic habitat (e.g., streamlined body shape and small mouth). The development of morphological differences within the same deep-water habitat for the PB- and PP-morphs highlights the potential of biotic factors and ecological interactions to promote further divergence in the evolution of polymorphism in a tentative incipient speciation process. The diversity of deep-water charr in this study represents a novelty in the Arctic charr polymorphism as a truly deep-water piscivore morph has to our knowledge not been described elsewhere.
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Affiliation(s)
- Sigrid Skoglund
- Department of Arctic and Marine Biology, University of Tromsø N-9037, Tromsø, Norway
| | - Anna Siwertsson
- Department of Arctic and Marine Biology, University of Tromsø N-9037, Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, University of Tromsø N-9037, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, University of Tromsø N-9037, Tromsø, Norway
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30
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Hendrichsen DK, Kristoffersen R, Gjelland KØ, Knudsen R, Kusterle S, Rikardsen AH, Henriksen EH, Smalås A, Olstad K. Transmission dynamics of the monogenean Gyrodactylus salaris under seminatural conditions. J Fish Dis 2015; 38:541-550. [PMID: 25039384 DOI: 10.1111/jfd.12263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/12/2014] [Accepted: 04/14/2014] [Indexed: 06/03/2023]
Abstract
Tracking individual variation in the dynamics of parasite infections in wild populations is often complicated by lack of knowledge of the epidemiological history of hosts. Whereas the dynamics and development of Gyrodactylus salaris Malmberg, 1957, on Atlantic salmon, Salmo salar L., are known from laboratory studies, knowledge about infection development on individual wild fishes is currently sparse. In this study, the dynamics of an infection of G. salaris on individually marked Atlantic salmon parr was followed in a section of a natural stream. During the 6-week experiment, the prevalence increased from 3.3 to 60.0%, with an average increase in intensity of 4.1% day(-1) . Survival analyses showed an initially high probability (93.6%) of staying uninfected by G. salaris, decreasing significantly to 37% after 6 weeks. The results showed that even at subarctic water temperatures and with an initially low risk of infection, the parasite spread rapidly in the Atlantic salmon population, with the capacity to reach 100% prevalence within a short summer season. The study thus track individual infection trajectories of Atlantic salmon living under near-natural conditions, providing an integration of key population parameters from controlled experiments with the dynamics of the epizootic observed in free-living living populations.
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31
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Eloranta AP, Kahilainen KK, Amundsen PA, Knudsen R, Harrod C, Jones RI. Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes. Ecol Evol 2015; 5:1664-75. [PMID: 25937909 PMCID: PMC4409414 DOI: 10.1002/ece3.1464] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 02/13/2015] [Accepted: 02/19/2015] [Indexed: 11/21/2022] Open
Abstract
Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes covering a marked gradient in size (0.5–1084 km2) and fish species richness (2–13 species). We expected top predators to shift from littoral to pelagic energy sources with increasing lake size, as the availability of pelagic prey resources and the competition for littoral prey are both likely to be higher in large lakes with multispecies fish communities. We also expected top predators to occupy a higher trophic position in lakes with greater fish species richness due to potential substitution of intermediate consumers (prey fish) and increased piscivory by top predators. Based on stable carbon and nitrogen isotope analyses, the mean reliance of Arctic charr on littoral energy sources showed a significant negative relationship with lake surface area, whereas the mean trophic position of Arctic charr, reflecting the lake food-chain length, increased with fish species richness. These results were supported by stomach contents data demonstrating a shift of Arctic charr from an invertebrate-dominated diet to piscivory on pelagic fish. Our study highlights that, because they determine the main energy source (littoral vs. pelagic) and the trophic position of generalist top predators, ecosystem size and fish diversity are particularly important factors influencing function and structure of food webs in high-latitude lakes.
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Affiliation(s)
- Antti P Eloranta
- Aquatic Ecology Department, Norwegian Institute for Nature Research P.O. Box 5685 Sluppen, NO-7485, Trondheim, Norway ; University of Jyväskylä, Department of Biological and Environmental Sciences P.O. Box 35, FIN-40014, Jyväskylä, Finland
| | - Kimmo K Kahilainen
- Department of Environmental Sciences, University of Helsinki P.O. Box 65, FIN-00014, Helsinki, Finland ; Kilpisjärvi Biological Station, University of Helsinki Käsivarrentie 14622, FIN-99490, Kilpisjärvi, Finland
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway P.O. Box 6050 Langnes, NO-9037, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway P.O. Box 6050 Langnes, NO-9037, Tromsø, Norway
| | - Chris Harrod
- Universidad de Antofagasta, Instituto de Ciencias Naturales Alexander von Humboldt Avenida Angamos 601, Antofagasta, Chile
| | - Roger I Jones
- University of Jyväskylä, Department of Biological and Environmental Sciences P.O. Box 35, FIN-40014, Jyväskylä, Finland
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Kuhn JA, Kristoffersen R, Knudsen R, Jakobsen J, Marcogliese DJ, Locke SA, Primicerio R, Amundsen PA. Parasite communities of two three-spined stickleback populations in subarctic Norway—effects of a small spatial-scale host introduction. Parasitol Res 2015; 114:1327-39. [DOI: 10.1007/s00436-015-4309-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 01/07/2015] [Indexed: 12/31/2022]
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33
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Bhat S, Amundsen PA, Knudsen R, Gjelland KØ, Fevolden SE, Bernatchez L, Præbel K. Speciation reversal in European whitefish (Coregonus lavaretus (L.)) caused by competitor invasion. PLoS One 2014; 9:e91208. [PMID: 24626131 PMCID: PMC3953381 DOI: 10.1371/journal.pone.0091208] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 02/10/2014] [Indexed: 11/19/2022] Open
Abstract
Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sympatric morphs utilizing the planktivorous and benthivorous food niche in many lakes. In 1993, Lake Skrukkebukta was invaded by vendace (Coregonus albula (L.)) which is a zooplanktivorous specialist. The vendace displaced the densely rakered whitefish from its preferred pelagic niche to the benthic habitat harbouring the large sparsely rakered whitefish. In this study, we investigate the potential influence of the vendace invasion on the breakdown of reproductive isolation between the two whitefish morphs. We inferred the genotypic and phenotypic differentiation between the two morphs collected at the arrival (1993) and 15 years after (2008) the vendace invasion using 16 microsatellite loci and gill raker numbers, the most distinctive adaptive phenotypic trait between them. The comparison of gill raker number distributions revealed two modes growing closer over 15 years following the invasion. Bayesian analyses of genotypes revealed that the two genetically distinct whitefish morphs that existed in 1993 had collapsed into a single population in 2008. The decline in association between the gill raker numbers and admixture values over 15 years corroborates the findings from the Bayesian analysis. Our study thus suggests an apparent decrease of reproductive isolation in a morph-pair of European whitefish within 15 years (≃ 3 generations) following the invasion of a superior trophic competitor (vendace) in a subarctic lake, reflecting a situation of "speciation in reverse".
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Affiliation(s)
- Shripathi Bhat
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
| | | | - Svein-Erik Fevolden
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
| | - Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
| | - Kim Præbel
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
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Præbel K, Knudsen R, Siwertsson A, Karhunen M, Kahilainen KK, Ovaskainen O, Ostbye K, Peruzzi S, Fevolden SE, Amundsen PA. Ecological speciation in postglacial European whitefish: rapid adaptive radiations into the littoral, pelagic, and profundal lake habitats. Ecol Evol 2013; 3:4970-86. [PMID: 24455129 PMCID: PMC3892361 DOI: 10.1002/ece3.867] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/03/2013] [Accepted: 10/09/2013] [Indexed: 11/09/2022] Open
Abstract
Understanding how a monophyletic lineage of a species diverges into several adaptive forms has received increased attention in recent years, but the underlying mechanisms in this process are still under debate. Postglacial fishes are excellent model organisms for exploring this process, especially the initial stages of ecological speciation, as postglacial lakes represent replicated discrete environments with variation in available niches. Here, we combine data of niche utilization, trophic morphology, and 17 microsatellite loci to investigate the diversification process of three sympatric European whitefish morphs from three northern Fennoscandian lakes. The morphological divergence in the gill raker number among the whitefish morphs was related to the utilization of different trophic niches and was associated with reproductive isolation within and across lakes. The intralacustrine comparison of whitefish morphs showed that these systems represent two levels of adaptive divergence: (1) a consistent littoral–pelagic resource axis; and (2) a more variable littoral–profundal resource axis. The results also indicate that the profundal whitefish morph has diverged repeatedly from the ancestral littoral whitefish morph in sympatry in two different watercourses. In contrast, all the analyses performed revealed clustering of the pelagic whitefish morphs across lakes suggesting parallel postglacial immigration with the littoral whitefish morph into each lake. Finally, the analyses strongly suggested that the trophic adaptive trait, number of gill rakers, was under diversifying selection in the different whitefish morphs. Together, the results support a complex evolutionary scenario where ecological speciation acts, but where both allopatric (colonization history) and sympatric (within watercourse divergence) processes are involved.
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Affiliation(s)
- Kim Præbel
- Department of Arctic and Marine Biology, University of Tromsø Tromsø, N-9037, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, University of Tromsø Tromsø, N-9037, Norway
| | - Anna Siwertsson
- Department of Arctic and Marine Biology, University of Tromsø Tromsø, N-9037, Norway
| | - Markku Karhunen
- Department of Biosciences, University of Helsinki PO Box 65, Helsinki, FI-00014, Finland
| | - Kimmo K Kahilainen
- Department of Environmental Sciences, University of Helsinki PO Box 65, Helsinki, FI-00014, Finland ; Kilpisjärvi Biological Station, University of Helsinki Käsivarrentie 14622, Kilpisjärvi, FI-99490, Finland
| | - Otso Ovaskainen
- Department of Biosciences, University of Helsinki PO Box 65, Helsinki, FI-00014, Finland
| | - Kjartan Ostbye
- Department of Biology, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo PO Box 1066, Blindern, Oslo, N-0315, Norway ; Department of Forestry and Wildlife Management, Hedmark University College Campus Evenstad, Elverum, NO-2418, Norway
| | - Stefano Peruzzi
- Department of Arctic and Marine Biology, University of Tromsø Tromsø, N-9037, Norway
| | - Svein-Erik Fevolden
- Department of Arctic and Marine Biology, University of Tromsø Tromsø, N-9037, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, University of Tromsø Tromsø, N-9037, Norway
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Sandlund OT, Gjelland KØ, Bøhn T, Knudsen R, Amundsen PA. Contrasting population and life history responses of a young morph-pair of European whitefish to the invasion of a specialised coregonid competitor, vendace. PLoS One 2013; 8:e68156. [PMID: 23844164 PMCID: PMC3700903 DOI: 10.1371/journal.pone.0068156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/30/2013] [Indexed: 11/19/2022] Open
Abstract
Invasions of non-native species represent a global problem of great scientific interest. Here we study in detail the response in population and life history characteristics of closely related native species, with divergent habitat preferences, that are impacted by an invading species over a sufficient time period to allow a new stable state to become established. A time series of 20 years starting at the first occurrence of the invader (vendace Coregonus albula (L.)) allows exploration of the long term population and life history response of two ecologically, morphologically, and genetically different native sympatric morphs (DR- and SR-) of congeneric whitefish C. lavaretus (L.). The whitefish morphs are taxonomically equally related to the invading vendace, but only the planktivorous DR-whitefish share its pelagic niche. We would expect that the ecological differences between the whitefish morphs may be used as a predictor of competitive effects. Vendace exhibited an initial boom-and-bust development, and has continued to fluctuate in density. The responses of the pelagic DR-whitefish were: i) an immediate habitat shift, ii) a subsequent population decline caused by increased annual mortality, and iii) a new stable state at a lower density and apparently relaxed competition. The ecologically more distant benthivorous SR-whitefish also showed significant, but a much more limited response during this process, indicating damped indirect interactions through the food-web. This long-term case-study found that in two native eco-species equally related to the invader, only one of the eco-species was highly affected. Direct competition for resources is obviously important for species interactions, whereas the taxonomic relatedness per se seems to offer little predictive power for invasion effects.
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Siwertsson A, Knudsen R, Adams CE, Præbel K, Amundsen PA. Parallel and non-parallel morphological divergence among foraging specialists in European whitefish (Coregonus lavaretus). Ecol Evol 2013; 3:1590-602. [PMID: 23789070 PMCID: PMC3686194 DOI: 10.1002/ece3.562] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 11/19/2022] Open
Abstract
Parallel phenotypic evolution occurs when independent populations evolve similar traits in response to similar selective regimes. However, populations inhabiting similar environments also frequently show some phenotypic differences that result from non-parallel evolution. In this study, we quantified the relative importance of parallel evolution to similar foraging regimes and non-parallel lake-specific effects on morphological variation in European whitefish (Coregonus lavaretus). We found evidence for both lake-specific morphological characteristics and parallel morphological divergence between whitefish specializing in feeding on profundal and littoral resources in three separate lakes. Foraging specialists expressed similar phenotypes in different lakes in both overall body shape and selected measured morphological traits. The morphology of the two whitefish specialists resembled that predicted from other fish species, supporting the conclusion of an adaptive significance of the observed morphological characteristics. Our results indicate that divergent natural selection resulting from foraging specialization is driving and/or maintaining the observed parallel morphological divergence. Whitefish in this study may represent an early stage of divergence towards the evolution of specialized morphs.
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Affiliation(s)
- Anna Siwertsson
- Department of Arctic and Marine Biology, University of Tromsø N-9037 Tromsø, Norway
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Winger AC, Kristoffersen R, Knudsen R. Rapid transmission of Gyrodactylus salaris (Malmberg, 1957) between live Arctic charr, Salvelinus alpinus (L.), fry. J Fish Dis 2012; 35:781-784. [PMID: 22882612 DOI: 10.1111/j.1365-2761.2012.01419.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Revised: 03/30/2012] [Accepted: 04/12/2012] [Indexed: 06/01/2023]
Affiliation(s)
- A C Winger
- Akershus County Council, The Central Administration, Sentrum, Oslo
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Amundsen PA, Lafferty KD, Knudsen R, Primicerio R, Kristoffersen R, Klemetsen A, Kuris AM. New parasites and predators follow the introduction of two fish species to a subarctic lake: implications for food-web structure and functioning. Oecologia 2012; 171:993-1002. [PMID: 23053223 PMCID: PMC3612402 DOI: 10.1007/s00442-012-2461-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 08/31/2012] [Indexed: 11/29/2022]
Abstract
Introduced species can alter the topology of food webs. For instance, an introduction can aid the arrival of free-living consumers using the new species as a resource, while new parasites may also arrive with the introduced species. Food-web responses to species additions can thus be far more complex than anticipated. In a subarctic pelagic food web with free-living and parasitic species, two fish species (arctic charr Salvelinus alpinus and three-spined stickleback Gasterosteus aculeatus) have known histories as deliberate introductions. The effects of these introductions on the food web were explored by comparing the current pelagic web with a heuristic reconstruction of the pre-introduction web. Extinctions caused by these introductions could not be evaluated by this approach. The introduced fish species have become important hubs in the trophic network, interacting with numerous parasites, predators and prey. In particular, five parasite species and four predatory bird species depend on the two introduced species as obligate trophic resources in the pelagic web and could therefore not have been present in the pre-introduction network. The presence of the two introduced fish species and the arrival of their associated parasites and predators increased biodiversity, mean trophic level, linkage density, and nestedness; altering both the network structure and functioning of the pelagic web. Parasites, in particular trophically transmitted species, had a prominent role in the network alterations that followed the introductions.
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Affiliation(s)
- Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, Tromso, Norway.
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Siwertsson A, Knudsen R, Præbel K, Adams CE, Newton J, Amundsen PA. Discrete foraging niches promote ecological, phenotypic, and genetic divergence in sympatric whitefish (Coregonus lavaretus). Evol Ecol 2012. [DOI: 10.1007/s10682-012-9607-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Amundsen PA, Kashulin NA, Terentjev P, Gjelland KØ, Koroleva IM, Dauvalter VA, Sandimirov S, Kashulin A, Knudsen R. Heavy metal contents in whitefish (Coregonus lavaretus) along a pollution gradient in a subarctic watercourse. Environ Monit Assess 2011; 182:301-316. [PMID: 21287264 DOI: 10.1007/s10661-011-1877-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 01/18/2011] [Indexed: 05/30/2023]
Abstract
Metallurgic industry is a source of serious environmental pollution related to the emission of heavy metals. Freshwater systems are focal points for pollution, acting as sinks for contaminants that may end up in fish and humans. The Pasvik watercourse in the border area between Finland, Norway and Russia is located in the vicinity of the Pechenganickel metallurgic enterprises, and the lower part of the watershed drains the Nikel smelters directly through Lake Kuetsjarvi. Heavy metal (Ni, Cu, Cd, Zn, Pb and Hg) concentrations in environment (water and sediments) and whitefish Coregonus lavaretus tissue (gills, liver, kidney and muscle) were contrasted between five lake localities situated along a spatial gradient of increasing distance (5-100 km) to the smelters. The heavy metal concentrations, in particular Ni, Cu and Cd, were highly elevated in Kuetsjarvi, but steeply declined with increasing distance to the smelters and were moderate or low in the other four localities. The study demonstrates that the majority of metal emissions and runoffs are deposited near the pollution source, and only moderate amounts of the heavy metal contaminants seem to be transported at further distances. Bioaccumulation of Hg occurred in all investigated tissues, and higher Hg concentrations in planktivorous versus benthivorous whitefish furthermore indicated that pelagic foraging is associated with higher levels of Hg biomagnification. Potential population ecology impacts of high heavy metal contaminations where mainly observed in whitefish in Kuetsjarvi, which showed depletions in growth rate, condition factor and size and age at maturation.
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Affiliation(s)
- Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromsø, Norway.
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Knudsen R, Siwertsson A, Adams CE, Garduño-Paz M, Newton J, Amundsen PA. Temporal stability of niche use exposes sympatric Arctic charr to alternative selection pressures. Evol Ecol 2010. [DOI: 10.1007/s10682-010-9451-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Winger AC, Kristoffersen R, Siikavuopio SI, Knudsen R. Experiments to test if allopatric Salvelinus alpinus are suitable year-round hosts of Gyrodactylus salaris (Monogenea). J Fish Biol 2009; 74:1476-1486. [PMID: 20735647 DOI: 10.1111/j.1095-8649.2009.02215.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
There has been an increased focus on Salvelinus alpinus as a potential long-term host to Gyrodactylus salaris and, here, both susceptibility to G. salaris and ability to sustain a parasite population seasonally, was tested using fry and parr of S. alpinus from the River Skibotnelva, northern Norway. Fry were highly susceptible. Gyrodactylus salaris survived on allopatric S. alpinus parr during the 5 month-long winter when water temperatures were c. 1 degrees C. Salvelinus alpinus fry also maintained a pulse of G. salaris infection for over 155 days from early May until autumn. Gyrodactylus salaris are thus able to reproduce and survive on S. alpinus for long periods and at low water temperatures. In spring, newly hatched fry of S. alpinus may serve as an important host to maintain a G. salaris metapopulation within a river system. The results suggest that S. alpinus are adequate long-term hosts of G. salaris independent of the presence of the co-occurring highly susceptible S. salar.
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Affiliation(s)
- A C Winger
- Norwegian College of Fishery Science, University of Tromsø, N-9037 Norway.
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Amundsen PA, Lafferty KD, Knudsen R, Primicerio R, Klemetsen A, Kuris AM. Food web topology and parasites in the pelagic zone of a subarctic lake. J Anim Ecol 2009; 78:563-72. [DOI: 10.1111/j.1365-2656.2008.01518.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Jeukens J, Bittner D, Knudsen R, Bernatchez L. Candidate Genes and Adaptive Radiation: Insights from Transcriptional Adaptation to the Limnetic Niche among Coregonine Fishes (Coregonus spp., Salmonidae). Mol Biol Evol 2008; 26:155-66. [DOI: 10.1093/molbev/msn235] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Persson L, Amundsen PA, De Roos AM, Klemetsen A, Knudsen R, Primicerio R. Culling Prey Promotes Predator Recovery--Alternative States in a Whole-Lake Experiment. Science 2007; 316:1743-6. [PMID: 17588929 DOI: 10.1126/science.1141412] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Many top-predator fish stocks in both freshwater and marine systems have collapsed as a result of overharvesting. Consequently, some of these communities have shifted into seemingly irreversible new states. We showed, for predators feeding on prey that exhibit food-dependent growth, that culling of fish prey may promote predator recovery. We removed old stunted individuals of a prey-fish species in a large, low-productive lake, which caused an increase in the availability of small-sized prey and allowed the predator to recover. The shift in community state has been sustained for more than 15 years after the cull ended and represents an experimental demonstration of an alternative stable state in a large-scale field system. Because most animals exhibit food-dependent growth, shifts into alternative stable states resulting from overcompensating prey growth may be common in nature and may require counterintuitive management strategies.
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Affiliation(s)
- Lennart Persson
- Department of Ecology and Environmental Science, Umeå University, S-901 87 Umeå, Sweden.
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Abstract
This study reports the results and complications from treating recurrent hip dislocations with a constrained liner (CL) after total hip arthroplasty (THA). Forty patients who had a CL inserted as a secondary prophylactic treatment were retrospectively reviewed after a median observation period of 27 months (range 7-77 months). During the observation period five patients had to be revised: one for deep infection and four on account of re-dislocations. Our results indicate that patients with recurrent THA dislocations can be treated with a CL and has a satisfactory low complication rate and a relatively low risk of re-dislocation.
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Affiliation(s)
- R Knudsen
- Department of Orthopedics, Odense University Hospital, Odense, Denmark.
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Abstract
1. Intraspecific competition for restricted food resources is considered to play a fundamental part in density dependence of somatic growth and other population characteristics, but studies simultaneously addressing the interrelationships between population density, food acquisition and somatic growth have been missing. 2. We explored the food consumption and individual growth rates of Arctic charr Salvelinus alpinus in a long-term survey following a large-scale density manipulation experiment in a subarctic lake. 3. Prior to the initiation of the experiment, the population density was high and the somatic growth rates low, revealing a severely overcrowded and stunted fish population. 4. During the 6-year period of stock depletion the population density of Arctic charr was reduced with about 75%, resulting in an almost twofold increase in food consumption rates and enhanced individual growth rates of the fish. 5. Over the decade following the density manipulation experiment, the population density gradually rose to intermediate levels, accompanied by corresponding reductions in food consumption and somatic growth rates. 6. The study revealed negative relationships with population density for both food consumption and individual growth rates, reflecting a strong positive correlation between quantitative food intake and somatic growth rates. 7. Both the growth and consumption rate relationships with population density were well described by negative power curves, suggesting that large density perturbations are necessary to induce improved feeding conditions and growth rates in stunted fish populations. 8. The findings demonstrate that quantitative food consumption represents the connective link between population density and individual growth rates, apparently being highly influenced by intraspecific competition for limited resources.
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Affiliation(s)
- Per-Arne Amundsen
- Department of Aquatic BioSciences, Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway.
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