1
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Wynne R, Kaufmann J, Coughlan J, Phillips KP, Waters C, Finlay RW, Rogan G, Poole R, McGinnity P, Reed TE. Autumn outmigrants in brown trout (Salmo trutta) are not a demographic dead-end. JOURNAL OF FISH BIOLOGY 2023; 102:1327-1339. [PMID: 36911993 DOI: 10.1111/jfb.15377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/10/2023] [Indexed: 06/09/2023]
Abstract
Genetic identity analysis and PIT (passive integrated transponder) tagging were used to examine the freshwater return rates and phenotypic characteristics of n = 1791 downstream migrating juvenile Salmo trutta in the Burrishoole catchment (northwest Ireland) across the period September 2017 to December 2020. In this system, juveniles out-migrate (move from freshwater into brackish or marine habitats) in every month of the year, with distinct seasonal peaks in spring (March through June; mostly silvered smolts) and autumn (September through December; mostly younger, unsilvered fry or parr). Both types exhibited a sex-bias towards females, which was stronger in spring (78% females) than in autumn outmigrants (67%). Sixty-nine returning fish were matched back to previous juvenile outmigrants, and similar return rates were found for spring outmigrants (5.0%), autumn outmigrants (3.3%) and fish that out-migrated outside of spring or autumn (2.8%). Spring and autumn outmigrants returned at similar dates (typically mid to late July), but autumn fish were away for longer periods (median = 612 days; spring outmigrants = 104 days). Autumn outmigrants were 25% smaller than spring outmigrants at outmigration and 6% smaller on their return, and within both groups smaller/younger outmigrants spent longer away than larger/older outmigrants. Autumn outmigrants were more likely to return unsilvered as "slob" trout (84%) than spring outmigrants (31%), suggesting they make greater use of brackish habitats that might be safer, but less productive, than fully marine habitats. Nonetheless, both types also produced silvered "sea trout" (≥1+ sea-age), implying neither is locked into a single life-history strategy. The findings emphasise that autumn outmigrants and the transitional habitats that support their persistence should not be overlooked in salmonid management and conservation.
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Affiliation(s)
- Robert Wynne
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
| | | | - Jamie Coughlan
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
| | - Karl P Phillips
- Canadian Rivers Institute, University of New Brunswick, Fredericton, New Brunswick, Canada
| | | | - Ross W Finlay
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
- Marine Institute, Furnace, Newport, Co. Mayo, Ireland
| | - Ger Rogan
- Marine Institute, Furnace, Newport, Co. Mayo, Ireland
| | - Russell Poole
- Marine Institute, Furnace, Newport, Co. Mayo, Ireland
| | - Philip McGinnity
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
- Marine Institute, Furnace, Newport, Co. Mayo, Ireland
| | - Thomas E Reed
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
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2
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Simmons OM, Britton JR, Gillingham PK, Nevoux M, Riley WD, Rivot E, Gregory SD. Predicting how environmental conditions and smolt body length when entering the marine environment impact individual Atlantic salmon Salmo salar adult return rates. JOURNAL OF FISH BIOLOGY 2022; 101:378-388. [PMID: 34773399 DOI: 10.1111/jfb.14946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 11/02/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Populations of Atlantic salmon Salmo salar have experienced precipitous declines in abundance since the 1970s. This decline has been associated with reduced numbers of adult salmon returning to fresh water from their marine migration, i.e., their marine return rates (MRR). Thus, understanding the factors that affect MRR is of crucial conservation importance. The authors used a state-space model with a 13-year time series of individually tagged salmon mark-recapture histories on the River Frome, southern England, to test the effect of smolt body length on their MRR. In addition to smolt length, the model tested for the influence of environmental covariates that were representative of the conditions experienced by the smolts in the early stages of their seaward migration, i.e., from the lower river to the estuary exit. The model indicated that, even when accounting for environmental covariates, smolt body length was an important predictor of MRR. Although larger smolts have a higher probability of returning to their natal river as adults than smaller smolts, and one-sea-winter salmon have a survival rate twice as high as multi-sea-winter salmon, the actual biological mechanisms underpinning this phenomenon remain uncertain. These results have important applications for salmon conservation, as efforts to bolster salmon populations in the freshwater environment should consider methods to improve smolt quality (i.e., body size) as well as smolt quantity.
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Affiliation(s)
- Olivia Meredith Simmons
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, UK
- Salmon and Trout Research Centre, Game and Wildlife Conservation Trust, Wareham, UK
| | - J Robert Britton
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, UK
| | - Phillipa K Gillingham
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, UK
| | - Marie Nevoux
- DECOD, Ecosystem Dynamics and Sustainability, Institut Agro, INRAE, Ifremer, Rennes, France
- MIAME-Management of Diadromous Fish in Their Environment, OFB, INRAE, Institut Agro, Univ Pau & Pays Adour/E2S Uppa, Rennes, France
| | - William D Riley
- The Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, UK
| | - Etienne Rivot
- DECOD, Ecosystem Dynamics and Sustainability, Institut Agro, INRAE, Ifremer, Rennes, France
- MIAME-Management of Diadromous Fish in Their Environment, OFB, INRAE, Institut Agro, Univ Pau & Pays Adour/E2S Uppa, Rennes, France
| | - Stephen D Gregory
- Salmon and Trout Research Centre, Game and Wildlife Conservation Trust, Wareham, UK
- The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK
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3
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Bøe K, Robertson MJ, Fleming IA, Power M. Evaluating the effect of dorsal muscle biopsies on adult Atlantic salmon growth and marine return rates. CONSERVATION PHYSIOLOGY 2020; 8:coz099. [PMID: 32523699 PMCID: PMC7268101 DOI: 10.1093/conphys/coz099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/19/2019] [Accepted: 11/06/2019] [Indexed: 06/11/2023]
Abstract
Increasing conservation and animal-welfare concerns have driven the development of non-lethal sampling of fish populations, with the use of muscle tissue biopsies now being routinely applied as a sampling method in the wild. Crucial to the success of non-lethal sampling, however, is an evaluation of the short- and long-term consequences of the treatment and ultimately the determination of how these may affect organism mortality and other fitness-related traits. The current study evaluated the use of a dorsal muscle biopsies on post-spawned Atlantic salmon emigrating to sea and undertaking a 2-month long-feeding migration before returning to spawn. Using mark-recapture, return rates and growth were compared between fish that were biopsied and externally tagged, and a control group tagged only with external tags. The biopsy treatment showed no lasting effects on fish as estimated from the two key fitness-related parameters. Results, therefore, suggest the technique can be more widely applied to gather information on marine migrating Atlantic salmon and other anadromous fishes that can be intercepted as they descend and ascend rivers during seasonal migrations. Coupled with modern tagging technologies, the use of biopsies may facilitate an improved understanding of movement and its consequences in terms of feeding patterns and growth.
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Affiliation(s)
- Kristin Bøe
- Department of Ocean Sciences, Memorial University, St. John’s, NL A1K 3E6, Canada
| | | | - Ian A Fleming
- Department of Ocean Sciences, Memorial University, St. John’s, NL A1K 3E6, Canada
| | - Michael Power
- Department of Biology, Waterloo University, Waterloo, Ontario, Canada
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4
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Hertz M, Jensen L, Pertoldi C, Aarestrup K, Thomsen S, Alstrup A, Asmus H, Madsen S, Svendsen J. Investigating fish migration, mortality, and physiology to improve conservation planning of anadromous salmonids: a case study on the endangered North Sea houting (Coregonus oxyrinchus). CAN J ZOOL 2019. [DOI: 10.1139/cjz-2019-0045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Understanding migratory behavior, mortality, and physiology is essential for conservation of many species, particularly anadromous fish. In this study, freshwater and marine migrations of the endangered salmonid North Sea houting (Coregonus oxyrinchus (Linnaeus, 1758)) were investigated using telemetry. Furthermore, physiological samples were collected from North Sea houting and from resident and anadromous populations of the closely related European whitefish (Coregonus lavaretus (Linnaeus, 1758)) to compare hypo-osmotic tolerances. On average, North Sea houting spent 193 days at sea where the mortality was 36%. Most fish returned from sea in the autumn, and river entry correlated inversely with river temperature and positively with discharge. Fish spent an average of 49 days in the estuarine area. Artificial lakes negatively affected migration speeds. Migration speeds did not differ consistently between individuals (i.e., not a repeatable trait) but correlated positively with water temperature. Fish arrived at spawning areas in November. In the post-spawning state, Na+/K+-ATPase activities were elevated in North Sea houting and anadromous whitefish compared with resident whitefish, while osmolality was elevated only in North Sea houting. Our study provides important information for conservation planning related to the Habitat Directive of the European Union that lists the North Sea houting as critically endangered.
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Affiliation(s)
- M. Hertz
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark
| | - L.F. Jensen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark
| | - C. Pertoldi
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark
- Aalborg Zoo, Mølleparkvej 63, 9000, Aalborg, Denmark
| | - K. Aarestrup
- National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - S.N. Thomsen
- Department of Chemistry and Bioscience, Section of Biology and Environmental Science, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark
| | - A.K.O. Alstrup
- Department of Nuclear Medicine and PET Center, Institute of Clinical Medicine, Aarhus University Hospital, Nørrebrogade 44, 10C, 8000 Aarhus, Denmark
| | - H. Asmus
- Alfred Wegener Institute, Hafenstraße 43, D-25992 List, Sylt, Germany
| | - S.S. Madsen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - J.C. Svendsen
- National Institute of Aquatic Resources, Technical University of Denmark, Jægersborg Alle 1, 2920, Denmark
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5
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Jonsson B, Jonsson N, Jonsson M. Supportive breeders of Atlantic salmon
Salmo salar
have reduced fitness in nature. CONSERVATION SCIENCE AND PRACTICE 2019. [DOI: 10.1111/csp2.85] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Bror Jonsson
- Department of Landscape EcologyNorwegian Institute for Nature Research Oslo Norway
| | - Nina Jonsson
- Department of Landscape EcologyNorwegian Institute for Nature Research Oslo Norway
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6
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Freshwater C, Trudel M, Beacham TD, Gauthier S, Johnson SC, Neville CE, Juanes F. Individual variation, population-specific behaviours and stochastic processes shape marine migration phenologies. J Anim Ecol 2018; 88:67-78. [PMID: 29790171 DOI: 10.1111/1365-2656.12852] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/05/2018] [Indexed: 11/27/2022]
Abstract
The phenology of long-distance migrations can influence individual fitness, moderate population dynamics and regulate the availability of ecosystem services to other trophic levels. Phenology varies within and among populations, and can be influenced by conditions individuals experience both prior to departure and encounter en route. Assessing how intrinsic and extrinsic factors (e.g., individual physical condition vs. environmental conditions) interact to influence variation in migratory phenologies across ecological scales is often limited due to logistical constraints associated with tracking large numbers of individuals from multiple populations simultaneously. We used two natural tags, DNA and otolith microstructure analysis, to estimate the relative influence of individual traits (life-history strategy, body size at departure and growth during migration), population-specific behaviours and interannual variability on the phenology of marine migrations in juvenile sockeye salmon Oncorhynchus nerka. We show that the timing and duration of juvenile sockeye salmon migrations were correlated with both life-history strategy and body size, while migration duration was also correlated with departure timing and growth rates during migration. Even after accounting for the effect of individual traits, several populations exhibited distinct migration phenologies. Finally, we observed substantial interannual and residual variation, suggesting stochastic environmental conditions moderate the influence of carry-over effects that develop prior to departure, as well as population-specific strategies. Migratory phenologies are shaped by complex interactions between drivers acting at multiple ecological and temporal scales. Given evidence that intraspecific diversity can stabilize ecological systems, conservation efforts should seek to maintain migratory variation among populations and preserve locally adapted phenotypes; however, variation within populations, which may buffer systems from environmental stochasticity, should also be regularly assessed and preserved.
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Affiliation(s)
- Cameron Freshwater
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Marc Trudel
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada.,Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada.,Fisheries and Oceans Canada, St. Andrews Biological Station, St. Andrews, New Brunswick, Canada
| | - Terry D Beacham
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada
| | - Stéphane Gauthier
- Fisheries and Oceans Canada, Institute of Ocean Sciences, Sidney, British Columbia, Canada
| | - Stewart C Johnson
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada
| | - Chrys-Ellen Neville
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada
| | - Francis Juanes
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
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7
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Kristoffersen AB, Qviller L, Helgesen KO, Vollset KW, Viljugrein H, Jansen PA. Quantitative risk assessment of salmon louse-induced mortality of seaward-migrating post-smolt Atlantic salmon. Epidemics 2017; 23:19-33. [PMID: 29233546 DOI: 10.1016/j.epidem.2017.11.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 10/26/2017] [Accepted: 11/29/2017] [Indexed: 10/18/2022] Open
Abstract
The Norwegian government recently implemented a new management system to regulate salmon farming in Norway, aiming to promote environmentally sustainable growth in the aquaculture industry. The Norwegian coast has been divided into 13 production zones and the volume of salmonid production in the zones will be regulated based on salmon lice effects on wild salmonids. Here we present a model for assessing salmon louse-induced mortality of seaward-migrating post-smolts of Atlantic salmon. The model quantifies expected salmon lice infestations and louse-induced mortality of migrating post-smolt salmon from 401 salmon rivers draining into Norwegian coastal waters. It is assumed that migrating post-smolts follow the shortest path from river outlets to the high seas, at constant progression rates. During this migration, fish are infested by salmon lice of farm origin according to an empirical infestation model. Furthermore, louse-induced mortality is estimated from the estimated louse infestations. Rivers draining into production zones on the West Coast of Norway were at the highest risk of adverse lice effects. In comparison, rivers draining into northerly production zones, along with the southernmost production zone, were at lower risk. After adjusting for standing stock biomass, estimates of louse-egg output varied by factors of up to 8 between production zones. Correlation between biomass adjusted output of louse infestation and densities of farmed salmon in the production zones suggests that a large-scale density-dependent host-parasite effect is a major driver of louse infestation rates and parasite-induced mortality. The estimates are sensitive to many of the processes in the chain of events in the model. Nevertheless, we argue that the model is suited to assess spatial and temporal risks associated with farm-origin salmon lice.
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Affiliation(s)
| | - Lars Qviller
- The Norwegian Veterinary Institute, PB. 750 Sentrum, N-0106 Oslo, Norway
| | - Kari Olli Helgesen
- The Norwegian Veterinary Institute, PB. 750 Sentrum, N-0106 Oslo, Norway
| | - Knut Wiik Vollset
- Uni Research Environment, LFI-Freshwater Biology, Nygårdsporten 112, N-5006 Bergen, Norway
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8
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Gosselin JL, Zabel RW, Anderson JJ, Faulkner JR, Baptista AM, Sandford BP. Conservation planning for freshwater-marine carryover effects on Chinook salmon survival. Ecol Evol 2017; 8:319-332. [PMID: 29321874 PMCID: PMC5756849 DOI: 10.1002/ece3.3663] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 02/03/2023] Open
Abstract
Experiences of migratory species in one habitat may affect their survival in the next habitat, in what is known as carryover effects. These effects are especially relevant for understanding how freshwater experience affects survival in anadromous fishes. Here, we study the carryover effects of juvenile salmon passage through a hydropower system (Snake and Columbia rivers, northwestern United States). To reduce the direct effect of hydrosystem passage on juveniles, some fishes are transported through the hydrosystem in barges, while the others are allowed to migrate in-river. Although hydrosystem survival of transported fishes is greater than that of their run-of-river counterparts, their relative juvenile-to-adult survival (hereafter survival) can be less. We tested for carryover effects using generalized linear mixed effects models of survival with over 1 million tagged Chinook salmon, Oncorhynchus tshawytscha (Walbaum) (Salmonidae), migrating in 1999-2013. Carryover effects were identified with rear-type (wild vs. hatchery), passage-type (run-of-river vs. transported), and freshwater and marine covariates. Importantly, the Pacific Decadal Oscillation (PDO) index characterizing cool/warm (i.e., productive/nonproductive) ocean phases had a strong influence on the relative survival of rear- and passage-types. Specifically, transportation benefited wild Chinook salmon more in cool PDO years, while hatchery counterparts benefited more in warm PDO years. Transportation was detrimental for wild Chinook salmon migrating early in the season, but beneficial for later season migrants. Hatchery counterparts benefited from transportation throughout the season. Altogether, wild fish could benefit from transportation approximately 2 weeks earlier during cool PDO years, with still a benefit to hatchery counterparts. Furthermore, we found some support for hypotheses related to higher survival with increased river flow, high predation in the estuary and plume areas, and faster migration and development-related increased survival with temperature. Thus, pre- and within-season information on local- and broad-scale conditions across habitats can be useful for planning and implementing real-time conservation programs.
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Affiliation(s)
- Jennifer L Gosselin
- School of Aquatic and Fishery Sciences University of Washington Seattle WA USA
| | - Richard W Zabel
- Northwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle WA USA
| | - James J Anderson
- School of Aquatic and Fishery Sciences University of Washington Seattle WA USA
| | - James R Faulkner
- Northwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle WA USA
| | | | - Benjamin P Sandford
- Northwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Pasco WA USA
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9
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Jonsson B, Jonsson M, Jonsson N. Influences of migration phenology on survival are size-dependent in juvenile Atlantic salmon (Salmo salar). CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0136] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long-distance migratory species can reduce mortality risks by synchronizing the migration event and create confusion by swamping predators with high densities. To reduce confusion, predators are known to primarily select aberrant prey. We hypothesized that at the start of their sea sojourn, particularly small and large Atlantic salmon (Salmo salar L., 1758) would spread the risk by also migrating at other times of the year. Based on data from the Norwegian river Imsa between 1976 and 2015, we found that juveniles, 14–19 cm in total length, started their sea sojourn during a short period between late April and early June. However, more than 20% of fish 13 cm or shorter migrated downstream between October and March, whereas 55% of fish 20 cm or longer migrated downstream between July and September. The regular-sized, spring-migrating juveniles had 2–3 times higher survival at sea than similar-sized conspecifics migrating to sea at other times of the year. The survival at sea for smaller juveniles was not improved by migration in spring relative to winter, and the survival of the largest juveniles was similar in spring and summer. Thus, the migration phenology appears adapted to survival in a high-risk environment by changing the timing according to their sizes.
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Affiliation(s)
- B. Jonsson
- Norwegian Institute for Nature Research, Gaustadalléen 21, N-0349 Oslo, Norway
| | - M. Jonsson
- Department of Physics, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo, Norway
| | - N. Jonsson
- Norwegian Institute for Nature Research, Gaustadalléen 21, N-0349 Oslo, Norway
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10
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Hellström G, Klaminder J, Finn F, Persson L, Alanärä A, Jonsson M, Fick J, Brodin T. GABAergic anxiolytic drug in water increases migration behaviour in salmon. Nat Commun 2016; 7:13460. [PMID: 27922016 PMCID: PMC5155400 DOI: 10.1038/ncomms13460] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 10/04/2016] [Indexed: 11/18/2022] Open
Abstract
Migration is an important life-history event in a wide range of taxa, yet many migrations are influenced by anthropogenic change. Although migration dynamics are extensively studied, the potential effects of environmental contaminants on migratory physiology are poorly understood. In this study we show that an anxiolytic drug in water can promote downward migratory behaviour of Atlantic salmon (Salmo salar) in both laboratory setting and in a natural river tributary. Exposing salmon smolt to a dilute concentration of a GABAA receptor agonist (oxazepam) increased migration intensity compared with untreated smolt. These results implicate that salmon migration may be affected by human-induced changes in water chemical properties, such as acidification and pharmaceutical residues in wastewater effluent, via alterations in the GABAA receptor function.
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Affiliation(s)
- Gustav Hellström
- Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden
| | - Jonatan Klaminder
- Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden
| | - Fia Finn
- Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden
| | - Lo Persson
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Anders Alanärä
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Micael Jonsson
- Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden
| | - Jerker Fick
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Tomas Brodin
- Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden
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11
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Jonsson B, Jonsson N, Albretsen J. Environmental change influences the life history of salmon Salmo salar in the North Atlantic Ocean. JOURNAL OF FISH BIOLOGY 2016; 88:618-637. [PMID: 26725985 DOI: 10.1111/jfb.12854] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 11/04/2015] [Indexed: 06/05/2023]
Abstract
Annual mean total length (LT) of wild one-sea-winter (1SW) Atlantic salmon Salmo salar of the Norwegian River Imsa decreased from 63 to 54 cm with a corresponding decrease in condition factor (K) for cohorts migrating to sea from 1976 to 2010. The reduction in LT is associated with a 40% decline in mean individual mass, from 2 to 1·2 kg. Hatchery fish reared from parental fish of the same population exhibited similar changes from 1981 onwards. The decrease in LT correlated negatively with near-surface temperatures in the eastern Norwegian Sea, thought to be the main feeding area of the present stock. Furthermore, S. salar exhibited significant variations in the proportion of cohorts attaining maturity after only one winter in the ocean. The proportion of S. salar spawning as 1SW fish was lower both in the 1970s and after 2000 than in the 1980s and 1990s associated with a gradual decline in post-smolt growth and smaller amounts of reserve energy in the fish. In wild S. salar, there was a positive association between post-smolt growth and the sea survival back to the River Imsa for spawning. In addition, among smolt year-classes, there were significant positive correlations between wild and hatchery S. salar in LT, K and age at maturity. The present changes may be caused by ecosystem changes following the collapse and rebuilding of the pelagic fish abundance in the North Atlantic Ocean, a gradual decrease in zooplankton abundance and climate change with increasing surface temperature in the Norwegian Sea. Thus, the observed variation in the life-history traits of S. salar appears primarily associated with major changes in the pelagic food web in the ocean.
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Affiliation(s)
- B Jonsson
- Norwegian Institute for Nature Research, Landscape Ecology Department, Gaustadalléen 21, 0349 Oslo, Norway
| | - N Jonsson
- Norwegian Institute for Nature Research, Landscape Ecology Department, Gaustadalléen 21, 0349 Oslo, Norway
| | - J Albretsen
- Institute of Marine Research, Flødevigen Research Station, Nye Flødevigveien 20, 4817 His, Norway
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12
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Crossin GT, Hatcher BG, Denny S, Whoriskey K, Orr M, Penney A, Whoriskey FG. Condition-dependent migratory behaviour of endangered Atlantic salmon smolts moving through an inland sea. CONSERVATION PHYSIOLOGY 2016; 4:cow018. [PMID: 27293765 PMCID: PMC4877435 DOI: 10.1093/conphys/cow018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/18/2016] [Accepted: 04/23/2016] [Indexed: 05/20/2023]
Abstract
The Bras d'Or Lake watershed of Cape Breton Island, Nova Scotia, Canada is a unique inland sea ecosystem, UNESCO Biosphere Reserve and home to a group of regionally distinct Atlantic salmon (Salmo salar) populations. Recent population decreases in this region have raised concern about their long-term persistence. We used acoustic telemetry to track the migrations of juvenile salmon (smolts) from the Middle River into the Bras d'Or Lake and, subsequently, into the Atlantic Ocean. Roughly half of the tagged smolts transited the Bras d'Or Lakes to the Atlantic Ocean, using a migration route that took them through the Gulf of St Lawrence's northern exit at the Strait of Belle Isle (∼650 km from the home river) towards feeding areas in the Labrador Sea and Greenland. However, a significant fraction spent >70 days in the Lakes, suggesting that this population has an alternative resident form, in which smolts limit their migrations within the Bras d'Or. Smolts in good relative condition (as determined from length-to-mass relationships) tended to be residents, whereas fish in poorer condition were ocean migrants. We also found a covarying effect of river temperature that helped to predict residence vs. ocean migration. We discuss these results relative to their bioenergetic implications and provide suggestions for future studies aimed at the conservation of declining salmon populations in Canada.
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Affiliation(s)
- Glenn T Crossin
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Corresponding author: Department of Biology, Dalhousie University, P.O. Box 15000, Halifax, NS, Canada B3H 4R2. Tel: +1 (902) 494 4258.
| | - Bruce G Hatcher
- Bras d’Or Institute for Ecosystem Research, Cape Breton University, Sydney, Nova Scotia, Canada
| | - Shelley Denny
- Unima’ki Institute of Natural Resources, Eskasoni, Nova Scotia, Canada
| | - Kim Whoriskey
- Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michael Orr
- Bras d’Or Institute for Ecosystem Research, Cape Breton University, Sydney, Nova Scotia, Canada
| | - Alicia Penney
- Bras d’Or Institute for Ecosystem Research, Cape Breton University, Sydney, Nova Scotia, Canada
| | - Frederick G Whoriskey
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Ocean Tracking Network, Dalhousie University, Halifax, Nova Scotia, Canada
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Morita K, Nakashima A. Temperature seasonality during fry out-migration influences the survival of hatchery-reared chum salmon Oncorhynchus keta. JOURNAL OF FISH BIOLOGY 2015; 87:1111-1117. [PMID: 26377831 DOI: 10.1111/jfb.12767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 06/29/2015] [Indexed: 06/05/2023]
Abstract
Among years, fry-to-adult survival of hatchery-reared chum salmon Oncorhynchus keta was positively correlated with the length (in days) of the fry out-migration period with temperatures suitable for migration. Furthermore, survival decreased with increasing difference in mean temperature between May and June. Thus, prolonged out-migration periods increased the probability of survival from fry to adult, lending support to the hypothesis that long migration periods decrease the risk of mortality (bet-hedging), and increase the probability of migration when environmental conditions in fresh water and the ocean are suitable (match-mismatch).
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Affiliation(s)
- K Morita
- Hokkaido National Fisheries Research Institute, Fisheries Research Agency, 2-2 Nakanoshima, Toyohira-ku, Sapporo, 062-0922, Japan
| | - A Nakashima
- Hokkaido National Fisheries Research Institute, Fisheries Research Agency, 2-2 Nakanoshima, Toyohira-ku, Sapporo, 062-0922, Japan
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