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Westbury MV, Brown SC, Lorenzen J, O’Neill S, Scott MB, McCuaig J, Cheung C, Armstrong E, Valdes PJ, Samaniego Castruita JA, Cabrera AA, Blom SK, Dietz R, Sonne C, Louis M, Galatius A, Fordham DA, Ribeiro S, Szpak P, Lorenzen ED. Impact of Holocene environmental change on the evolutionary ecology of an Arctic top predator. SCIENCE ADVANCES 2023; 9:eadf3326. [PMID: 37939193 PMCID: PMC10631739 DOI: 10.1126/sciadv.adf3326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 06/09/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023]
Abstract
The Arctic is among the most climatically sensitive environments on Earth, and the disappearance of multiyear sea ice in the Arctic Ocean is predicted within decades. As apex predators, polar bears are sentinel species for addressing the impact of environmental variability on Arctic marine ecosystems. By integrating genomics, isotopic analysis, morphometrics, and ecological modeling, we investigate how Holocene environmental changes affected polar bears around Greenland. We uncover reductions in effective population size coinciding with increases in annual mean sea surface temperature, reduction in sea ice cover, declines in suitable habitat, and shifts in suitable habitat northward. Furthermore, we show that west and east Greenlandic polar bears are morphologically, and ecologically distinct, putatively driven by regional biotic and genetic differences. Together, we provide insights into the vulnerability of polar bears to environmental change and how the Arctic marine ecosystem plays a vital role in shaping the evolutionary and ecological trajectories of its inhabitants.
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Affiliation(s)
- Michael V. Westbury
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
| | - Stuart C. Brown
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
- Environment Institute and School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Department for Environment and Water, Adelaide, South Australia, Australia
| | - Julie Lorenzen
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
| | - Stuart O’Neill
- Environment Institute and School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Michael B. Scott
- Department of Anthropology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9L0G2, Canada
| | - Julia McCuaig
- Department of Anthropology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9L0G2, Canada
| | - Christina Cheung
- Department of Anthropology, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Edward Armstrong
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland
| | - Paul J. Valdes
- School of Geographical Sciences, University of Bristol, Bristol, UK
| | | | - Andrea A. Cabrera
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
| | - Stine Keibel Blom
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
| | - Rune Dietz
- Arctic Research Centre (ARC), Department of Ecoscience, Aarhus University, Frederiksborgvej 399, PO Box 358, Roskilde DK-4000, Denmark
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, Frederiksborgvej 399, Roskilde DK-4000, Denmark
| | - Christian Sonne
- Arctic Research Centre (ARC), Department of Ecoscience, Aarhus University, Frederiksborgvej 399, PO Box 358, Roskilde DK-4000, Denmark
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, Frederiksborgvej 399, Roskilde DK-4000, Denmark
| | - Marie Louis
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
- Greenland Institute of Natural Resources, Kivioq 2, PO Box 570, Nuuk 3900, Denmark
| | - Anders Galatius
- Section for Marine Mammal Research, Department of Ecoscience, Aarhus University, Frederiksborgvej 399, Roskilde DK-4000, Denmark
| | - Damien A. Fordham
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
- Environment Institute and School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Sofia Ribeiro
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
- Glaciology and Climate Department, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, Copenhagen DK-1350, Denmark
| | - Paul Szpak
- Department of Anthropology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9L0G2, Canada
| | - Eline D. Lorenzen
- Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen DK-1350, Denmark
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van der Grient J, Morley S, Arkhipkin A, Bates J, Baylis A, Brewin P, Harte M, White JW, Brickle P. The Falkland Islands marine ecosystem: A review of the seasonal dynamics and trophic interactions across the food web. ADVANCES IN MARINE BIOLOGY 2023; 94:1-68. [PMID: 37244676 DOI: 10.1016/bs.amb.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The Falkland Islands marine environment host a mix of temperate and subantarctic species. This review synthesizes baseline information regarding ontogenetic migration patterns and trophic interactions in relation to oceanographic dynamics of the Falkland Shelf, which is useful to inform ecosystem modelling. Many species are strongly influenced by regional oceanographic dynamics that bring together different water masses, resulting in high primary production which supports high biomass in the rest of the food web. Further, many species, including those of commercial interest, show complex ontogenetic migrations that separate spawning, nursing, and feeding grounds spatially and temporally, producing food web connections across space and time. The oceanographic and biological dynamics may make the ecosystem vulnerable to climatic changes in temperature and shifts in the surrounding area. The Falkland marine ecosystem has been understudied and various functional groups, deep-sea habitats and inshore-offshore connections are poorly understood and should be priorities for further research.
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Affiliation(s)
| | - Simon Morley
- British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
| | - Alexander Arkhipkin
- Falkland Islands Government, Directorate of Natural Resources, Fisheries Department, Stanley, Falkland Islands
| | - James Bates
- Falkland Islands Fishing Companies Association, Stanley, Falkland Islands
| | - Alastair Baylis
- South Atlantic Environmental Research Institute, Stanley, Falkland Islands
| | - Paul Brewin
- South Atlantic Environmental Research Institute, Stanley, Falkland Islands; Shallow Marine Surveys Group, Stanley, Falkland Islands
| | - Michael Harte
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
| | - J Wilson White
- Coastal Oregon Marine Experiment Station, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Corvallis, OR, United States
| | - Paul Brickle
- South Atlantic Environmental Research Institute, Stanley, Falkland Islands; School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
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Hinton B, Stockin KA, Bury SJ, Peters KJ, Betty EL. Isotopic Niche Analysis of Long-Finned Pilot Whales (Globicephala melas edwardii) in Aotearoa New Zealand Waters. BIOLOGY 2022; 11:biology11101414. [PMID: 36290319 PMCID: PMC9598128 DOI: 10.3390/biology11101414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/26/2022] [Accepted: 08/31/2022] [Indexed: 11/25/2022]
Abstract
Simple Summary Isotopic niche analyses can elucidate a species’ foraging ecology. Using isotopic values of δ13C, δ15N and δ34S, the isotopic niche of long-finned pilot whales (Globicephala melas edwardii) in Aotearoa New Zealand was investigated for animals that stranded in six different events across two locations between 2009 and 2017. Generalised additive models revealed that stranding event was a stronger predictor for δ13C and δ15N values than body length, sex, or reproductive status, indicating that spatiotemporal differences explained isotopic variation of G. m. edwardii in New Zealand waters better than ontogenetic factors. Abstract The quantification of a species’ trophic niche is important to understand the species ecology and its interactions with the ecosystem it resides in. Despite the high frequency of long-finned pilot whale (Globicephala melas edwardii) strandings on the Aotearoa New Zealand coast, their trophic niche remains poorly understood. To assess the isotopic niche of G. m. edwardii within New Zealand, ontogenetic (sex, total body length, age, maturity status, reproductive group) and spatiotemporal (stranding location, stranding event, and stranding year) variation were investigated. Stable isotopes of carbon (δ13C) and nitrogen (δ15N) were examined from skin samples of 125 G. m. edwardii (67 females and 58 males) collected at mass-stranding events at Onetahua Farewell Spit in 2009 (n = 20), 2011 (n = 20), 2014 (n = 27) and 2017 (n = 20) and at Rakiura Stewart Island in 2010 (n = 19) and 2011 (n = 19). Variations in δ34S values were examined for a subset of 36 individuals. General additive models revealed that stranding event was the strongest predictor for δ13C and δ15N values, whilst sex was the strongest predictor of δ34S isotopic values. Although similar within years, δ13C values were lower in 2014 and 2017 compared to all other years. Furthermore, δ15N values were higher within Farewell Spit 2017 compared to any other stranding event. This suggests that the individuals stranded in Farewell Spit in 2017 may have been feeding at a higher trophic level, or that the nitrogen baseline may have been higher in 2017 than in other years. Spatiotemporal differences explained isotopic variation of G. m. edwardii in New Zealand waters better than ontogenetic factors.
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Affiliation(s)
- Bethany Hinton
- Cetacean Ecology Research Group, School of Natural Sciences, Massey University, Auckland 0745, New Zealand
- Correspondence: (B.H.); (E.L.B.)
| | - Karen A. Stockin
- Cetacean Ecology Research Group, School of Natural Sciences, Massey University, Auckland 0745, New Zealand
| | - Sarah J. Bury
- Environmental Isotopes and Molecular Biology Group, National Institute of Water and Atmospheric Research, Wellington 6021, New Zealand
| | - Katharina J. Peters
- Cetacean Ecology Research Group, School of Natural Sciences, Massey University, Auckland 0745, New Zealand
- School of Earth and Environment, University of Canterbury, Christchurch 8041, New Zealand
- Evolutionary Genetics Group, Department of Anthropology, University of Zurich, 8057 Zurich, Switzerland
- Global Ecology, College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Emma L. Betty
- Cetacean Ecology Research Group, School of Natural Sciences, Massey University, Auckland 0745, New Zealand
- Correspondence: (B.H.); (E.L.B.)
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Ogilvy C, Constantine R, Bury SJ, Carroll EL. Diet variation in a critically endangered marine predator revealed with stable isotope analysis. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220470. [PMID: 35991335 PMCID: PMC9382206 DOI: 10.1098/rsos.220470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Understanding the foraging ecology of animals gives insights into their trophic relationships and habitat use. We used stable isotope analysis to understand the foraging ecology of a critically endangered marine predator, the Māui dolphin. We analysed carbon and nitrogen isotope ratios of skin samples (n = 101) collected from 1993 to 2021 to investigate temporal changes in diet and niche space. Genetic monitoring associated each sample with a DNA profile which allowed us to assess individual and population level changes in diet. Potential prey and trophic level indicator samples were also collected (n = 166; 15 species) and incorporated in Bayesian mixing models to estimate importance of prey types to Māui dolphin diet. We found isotopic niche space had decreased over time, particularly since the 2008 implementation of a Marine Mammal Sanctuary. We observed a decreasing trend in ∂13C and ∂15N values, but this was not linear and several fluctuations in isotope values occurred over time. The largest variation in isotope values occurred during an El Niño event, suggesting that prey is influenced by climate-driven oceanographic variables. Mixing models indicated relative importance of prey remained constant since 2008. The isotopic variability observed here is not consistent with individual specialization, rather it occurs at the population level.
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Affiliation(s)
- Courtney Ogilvy
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Rochelle Constantine
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
- Institute of Marine Science, University of Auckland, Auckland 1010, New Zealand
| | - Sarah J. Bury
- National Institute of Water and Atmospheric Research, Greta Point, Wellington 6021, New Zealand
| | - Emma L. Carroll
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
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Fioramonti NE, Ribeiro Guevara S, Becker YA, Riccialdelli L. Mercury transfer in coastal and oceanic food webs from the Southwest Atlantic Ocean. MARINE POLLUTION BULLETIN 2022; 175:113365. [PMID: 35114547 DOI: 10.1016/j.marpolbul.2022.113365] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/13/2022] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
The dynamics of contaminants, such as mercury (Hg), in marine trophic webs is a critical topic in the scientific community due to the high concentrations encountered in organisms. In this study we attempted to provide information on total Hg accumulation patterns and possible pathways of trophic transfers assessed in combination with δ13C and δ15N to understand how this contaminant permeates three sub-Antarctic food webs: the Beagle Channel (BC), the Atlantic coast of Tierra del Fuego (AC-TDF) and Burdwood Bank (BB). We found a site-specific pattern of Hg transfer and biomagnification processes, while the oceanic BB showed major Hg transfer through the pelagic domain, coastal sectors (BC and AC-TDF) indicate a general biodilution process but with Hg concentrations incrementing with the benthivory grade. This represents a dissimilar Hg bioavailability for marine consumers that rely on different diet and forage in different habitats, and may become an issue of important conservation concern for these southern areas.
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Affiliation(s)
- N E Fioramonti
- Centro Austral de Investigaciones Científicas (CADIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernardo Houssay 200, Ushuaia, Tierra del Fuego, Argentina.
| | - S Ribeiro Guevara
- Laboratorio de Análisis por Activación Neutrónica, Centro Atómico Bariloche, Av E. Bustillo Km 9.500, Bariloche, Argentina
| | - Y A Becker
- Centro Austral de Investigaciones Científicas (CADIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernardo Houssay 200, Ushuaia, Tierra del Fuego, Argentina
| | - L Riccialdelli
- Centro Austral de Investigaciones Científicas (CADIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernardo Houssay 200, Ushuaia, Tierra del Fuego, Argentina
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Hüne M, Friedlander AM, Ballesteros E, Caselle JE, Sala E. Assemblage structure and spatial diversity patterns of kelp forest-associated fishes in Southern Patagonia. PLoS One 2021; 16:e0257662. [PMID: 34543325 PMCID: PMC8452001 DOI: 10.1371/journal.pone.0257662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 09/07/2021] [Indexed: 11/28/2022] Open
Abstract
Knowledge of the ecology of the fish fauna associated with kelp (primarily Macrocystis pyrifera) forests in Southern Patagonia is scarce, especially in how abiotic and biotic variables influence their structure, diversity, and distribution. This information is important for the management and conservation of this unique ecosystem, which has minimal anthropogenic impacts at present. We analyzed data from 122 quantitative underwater transects conducted within kelp forests at 61 stations from Chile's southern Patagonian fjords to the Cape Horn and Diego Ramirez archipelagos and the southern tip of Argentina, including the Mitre Peninsula and Isla de los Estados. In total, 25 fish species belonging to 13 families were observed. Multivariate analysis indicated that there are significant differences in fish assemblage structure among locations and wave exposures, which was driven primarily by Patagonotothen sima and Paranotothenia magellanica, which occurred on exposed and semi-exposed stations. P. cornucola was mainly distributed across sheltered stations of the Kawésqar National Park. Temperature, salinity, depth, and kelp density influenced fish assemblage structure, with the highest diversity in areas with the lowest temperature and greater depth at Isla de los Estados. In contrast, species richness, diversity, abundance, and biomass were all lower in areas with high density of the understory kelp Lessonia spp., which might be driven by the absence of P. tessellata, P. squamiceps and P. cornucola, the most important species in terms of occurrence, abundance, and biomass. Our study provides the first broad-scale description of the fish assemblages associated with kelp forests along the southern cone of South America based on non-invasive visual transects, improving our knowledge of the distribution of fish assemblages across several environmental conditions in this vast and little-studied area.
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Affiliation(s)
- Mathias Hüne
- Centro de Investigación para la Conservación de los Ecosistemas Australes (ICEA), Punta Arenas, Chile
| | - Alan M. Friedlander
- Pristine Seas, National Geographic Society, Washington, DC, United States of America
- Hawaiʿi Institute of Marine Biology, University of Hawaiʿi, Kāneʻohe, Hawaiʿi, United States of America
| | | | - Jennifer E. Caselle
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Enric Sala
- Pristine Seas, National Geographic Society, Washington, DC, United States of America
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Feeding ecology of the long finned pilot whale, Globicephala melas edwardii, in the southwestern Atlantic Ocean, determined by stable isotopes analysis. Polar Biol 2021. [DOI: 10.1007/s00300-021-02908-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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8
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Louis M, Skovrind M, Garde E, Heide-Jørgensen MP, Szpak P, Lorenzen ED. Population-specific sex and size variation in long-term foraging ecology of belugas and narwhals. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202226. [PMID: 33972883 PMCID: PMC8074634 DOI: 10.1098/rsos.202226] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Intraspecific variation in resource use by individuals of different age, sex or size may reflect differing energetic requirements and physiological constraints. Males and females often show differences in diet owing to sexual size dimorphism, different life histories and/or habitat use. Here, we investigate how sex and size influence the long-term foraging ecology of belugas and narwhals in Greenland, using stable isotopes of carbon and nitrogen from bone collagen. We show that males have a higher trophic level and a larger ecological niche than females in West Greenland belugas and in East Greenland narwhals. In addition, for these two populations, we find that δ 15N increases with size, particularly in males. We hypothesize that sexual size dimorphism together with strong maternal investment drive these differences. By contrast, we find no differences in foraging ecology between sexes in West Greenland narwhals and observe no influence of size on trophic level. This may reflect the influence of interspecific competition in West Greenland, where the distributions of belugas and narwhals overlap, and/or geographical resource partitioning among different summer aggregations of narwhals. Our results suggest that sex and size variations in diet are population dependent, and probably the result of varying ecological interactions.
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Affiliation(s)
- Marie Louis
- Globe Institute, University of Copenhagen, Denmark
| | | | - Eva Garde
- Greenland Institute of Natural Resources, Copenhagen, Denmark
| | | | - Paul Szpak
- Trent University, Peterborough, Ontario, Canada
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Furuyama A, Yodo T, Funasaka N, Wakabayashi I, Oike T, Yoshioka M. Development of an analytical method to exclude the effect of decomposition on carbon and nitrogen stable isotope ratios using muscle samples collected from stranded narrow-ridged finless porpoise (Neophocaena asiaeorientalis). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8857. [PMID: 32533561 DOI: 10.1002/rcm.8857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 06/11/2023]
Abstract
UNLABELLED Carbon and nitrogen stable isotope ratios (i.e., δ13 C and δ15 N values) in soft tissues of cetaceans are reported to change on decomposition. Care should be taken when determining the values using samples collected from dead-stranded cetaceans. We have developed a new analytical method to exclude the effect of decomposition on δ13 C and δ15 N values using muscles from narrow-ridged finless porpoises (Neophocaena asiaeorientalis). METHODS The muscles from 53 fresh (bycatch and live-stranded individuals) and 213 dead-stranded individuals were analyzed by isotope ratio mass spectrometry combined with an elemental analyzer. The carbon and nitrogen content was compared between fresh and dead-stranded samples to investigate any decrease in the content with decomposition. In dead-stranded samples, the effect of changes in the carbon and nitrogen content and the C:N ratio (carbon/nitrogen) on δ13 C and δ15 N values was predicted by the generalized additive model (GAM). RESULTS The carbon and nitrogen content (mean ± SE) in the muscles of fresh samples was 0.462 ± 0.0019 mg/mg and 0.147 ± 0.0005 mg/mg, respectively, while the content of dead-stranded samples was lower: carbon: 0.441 ± 0.0033 mg/mg and nitrogen: 0.135 ± 0.0012 mg/mg. When using the GAM, knowledge of the carbon and nitrogen content and the C:N ratio improved the prediction precision. CONCLUSIONS Prediction by the GAM showed changes in δ13 C and δ15 N values with a change in carbon and nitrogen content. The effect of decomposition can be excluded in statistical analysis of stranded samples by using samples with carbon and nitrogen content and C:N ratio equivalent to those of fresh samples or by using the carbon and nitrogen content and C:N ratio as an explanatory variable in the GAM.
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Affiliation(s)
- Ayuma Furuyama
- Graduate School of Bioresources, Mie University, Tsu, Mie, 514-8507, Japan
| | - Taiga Yodo
- Graduate School of Bioresources, Mie University, Tsu, Mie, 514-8507, Japan
| | - Noriko Funasaka
- Graduate School of Bioresources, Mie University, Tsu, Mie, 514-8507, Japan
| | | | - Tatsuya Oike
- Minamichita Beachland Aquarium, Mihama, Aichi, 470-3233, Japan
| | - Motoi Yoshioka
- Graduate School of Bioresources, Mie University, Tsu, Mie, 514-8507, Japan
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10
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Bell O, Jones ME, Ruiz‐Aravena M, Hamede RK, Bearhop S, McDonald RA. Age-related variation in the trophic characteristics of a marsupial carnivore, the Tasmanian devil Sarcophilus harrisii. Ecol Evol 2020; 10:7861-7871. [PMID: 32760570 PMCID: PMC7391331 DOI: 10.1002/ece3.6513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 01/22/2023] Open
Abstract
Age-related changes in diet have implications for competitive interactions and for predator-prey dynamics, affecting individuals and groups at different life stages. To quantify patterns of variation and ontogenetic change in the diets of Tasmanian devils Sarcophilus harrisii, a threatened marsupial carnivore, we analyzed variation in the stable isotope composition of whisker tissue samples taken from 91 individual devils from Wilmot, Tasmania from December 2014 to February 2017. Both δ13C and δ15N decreased with increasing age in weaned Tasmanian devils, indicating that as they age devils rely less on small mammals and birds, and more on large herbivores. Devils <12 months old had broader group isotopic niches, as estimated by Bayesian standard ellipses (SEAB mode = 1.042) than devils from 12 to 23 months old (mode = 0.541) and devils ≥24 months old (mode = 0.532). Devils <24 months old had broader individual isotopic niches (SEAB mode range 0.492-1.083) than devils ≥24 months old (mode range 0.092-0.240). A decrease in δ15N from the older whisker sections to the more recently grown sections in devils <24 months old likely reflects the period of weaning in this species, as this pattern was not observed in devils ≥24 months old. Our data reveal changes in the isotopic composition of devil whiskers with increasing age, accompanied by a reduction in isotopic variation both among population age classes and within individuals, reflecting the effect of weaning in early life, and a likely shift from an initially diverse diet of small mammals, birds, and invertebrates towards increasing consumption of larger herbivores in adulthood.
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Affiliation(s)
- Olivia Bell
- Environment and Sustainability InstituteUniversity of ExeterPenrynUK
| | - Menna E. Jones
- School of Natural SciencesUniversity of TasmaniaHobartTas.Australia
| | - Manuel Ruiz‐Aravena
- School of Natural SciencesUniversity of TasmaniaHobartTas.Australia
- Department of Microbiology and ImmunologyMontana State UniversityBozemanMTUSA
| | | | - Stuart Bearhop
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
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Moorhouse‐Gann RJ, Kean EF, Parry G, Valladares S, Chadwick EA. Dietary complexity and hidden costs of prey switching in a generalist top predator. Ecol Evol 2020; 10:6395-6408. [PMID: 32724521 PMCID: PMC7381573 DOI: 10.1002/ece3.6375] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 01/07/2023] Open
Abstract
Variation in predator diet is a critical aspect of food web stability, health, and population dynamics of predator/ prey communities. Quantifying diet, particularly among cryptic species, is extremely challenging, however, and differentiation between demographic subsets of populations is often overlooked.We used prey remains and data taken postmortem from otter Lutra lutra to determine the extent to which dietary variation in a top predator was associated with biotic, spatial, and temporal factors.Biotic data (e.g., sex, weight, and length) and stomach contents were taken from 610 otters found dead across England and Wales between 1994 and 2010. Prey remains were identified to species where possible, using published keys and reference materials. Multi-model inference followed by model prediction was applied to test for and visualize the nature of associations.Evidence for widespread decline in the consumption of eels (Anguilla anguilla) reflected known eel population declines. An association between eel consumption and otter body condition suggested negative consequences for otter nutrition. Consumption of Cottus gobio and stickleback spp. increased, but was unlikely to compensate (there was no association with body condition). More otters with empty stomachs were found over time. Otter sex, body length, and age-class were important biotic predictors of the prey species found, and season, region, and distance from the coast were important abiotic predictors.Our study is unique in its multivariate nature, broad spatial scale, and long-term dataset. Inclusion of biotic data allowed us to reveal important differences in costs and benefits of different prey types, and differences between demographic subsets of the population, overlaid on spatial and temporal variation. Such complexities in otter diet are likely to be paralleled in other predators, and detailed characterization of diet should not be overlooked in efforts to conserve wild populations.
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Affiliation(s)
| | | | - Gareth Parry
- Gloucestershire Wildlife TrustThe Conservation CentreGloucesterUK
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12
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Using a recreational grade echosounder to quantify the potential prey field of coastal predators. PLoS One 2019; 14:e0217013. [PMID: 31116761 PMCID: PMC6530895 DOI: 10.1371/journal.pone.0217013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/02/2019] [Indexed: 11/19/2022] Open
Abstract
Quantifying the distribution of prey greatly improves models of habitat use by marine predators and can assist in determining threats to both predators and prey. Small epipelagic fishes are important prey for many predators yet their distribution is difficult to quantify due to extreme patchiness. This study explores the use of recreational grade echosounders (RGE) to quantify school characteristics of epipelagic fish and link their distribution to that of their predators at Banks Peninsula, New Zealand. The hydro-acoustic system was ground-truthed with 259 schools of epipelagic fish. During 2015 and 2016, 136 hydro-acoustic surveys were conducted with concurrent observations of Hector's dolphin (Cephalorhynchus hectori) and little penguins (Eudyptula minor). The relative abundance of the two predator species during surveys was modelled according to the relative abundance of potential prey using generalised additive mixed models. Schools of epipelagic fish were readily detected by the RGE system and were more abundant in summer compared to winter. The models performed well, explaining 43% and 37% of the deviance in relative abundances of dolphins and penguins respectively. This is the first study to link the distribution of Hector's dolphin to that of their epipelagic prey and confirms the utility of RGE in studies of habitat use in marine predators. Limitations associated with a lack of formal acoustic calibration and data formatting can be overcome and would make RGE valuable, inexpensive tools for investigating variability in populations of small pelagic fishes.
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Winter is cool: spatio-temporal patterns of the squat lobster Munida gregaria and the Fuegian sprat Sprattus fuegensis in a sub-Antarctic estuarine environment. Polar Biol 2018. [DOI: 10.1007/s00300-018-2394-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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De Meyer J, Goethals T, Van Wassenbergh S, Augustijns T, Habraken J, Hellemans J, Vandewiele V, Dhaene J, Bouillart M, Adriaens D. Dimorphism throughout the European eel's life cycle: are ontogenetic changes in head shape related to dietary differences? J Anat 2018; 233:289-301. [PMID: 29855043 PMCID: PMC6081510 DOI: 10.1111/joa.12836] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2018] [Indexed: 01/05/2023] Open
Abstract
A well-known link exists between an organism's ecology and morphology. In the European eel, a dimorphic head has been linked to differences in feeding ecology, with broad-headed eels consuming harder prey items than narrow-headed ones. Consequently, we hypothesized that broad-heads should exhibit a cranial musculoskeletal system that increases bite force and facilitates the consumption of harder prey. Using 3D-reconstructions and a bite model, we tested this hypothesis in two life stages: the sub-adult yellow eel stage and its predecessor, the elver eel stage. This allowed us to test whether broad- and narrow-headed phenotypes show similar trait differences in both life stages and whether the dimorphism becomes more pronounced during ontogeny. We show that broad-headed eels in both stages have larger jaw muscles and a taller coronoid, which are associated with higher bite forces. This increased bite force together with the elongated upper and lower jaws in broad-headed eels can also improve grip during spinning behavior, which is used to manipulate hard prey. Head shape variation in European eel is therefore associated with musculoskeletal variation that can be linked to feeding ecology. However, although differences in muscle volume become more pronounced during ontogeny, this was not the case for skeletal features.
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Affiliation(s)
- J. De Meyer
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - T. Goethals
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - S. Van Wassenbergh
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
- Département Adaptations du VivantUMR 7179 C.N.R.S/M.N.H.N.Paris Cedex 05France
| | - T. Augustijns
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - J. Habraken
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - J. Hellemans
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - V. Vandewiele
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - J. Dhaene
- Department of Physics and AstronomyUGCT – Radiation PhysicsGhent UniversityGhentBelgium
| | - M. Bouillart
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - D. Adriaens
- Evolutionary Morphology of VertebratesGhent UniversityGhentBelgium
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Paso Viola MN, Riccialdelli L, Negri MF, Panebianco MV, Panarello HO, Cappozzo HL. Intra-specific isotope variations of franciscana dolphin Pontoporia blainvillei regarding biological parameters and distinct environments. Mamm Biol 2017. [DOI: 10.1016/j.mambio.2017.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Hohn AA, Thomas L, Carmichael RH, Litz J, Clemons-Chevis C, Shippee SF, Sinclair C, Smith S, Speakman TR, Tumlin MC, Zolman ES. Assigning stranded bottlenose dolphins to source stocks using stable isotope ratios following the Deepwater Horizon oil spill. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00783] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Loizaga de Castro R, Saporiti F, Vales DG, García NA, Cardona L, Crespo EA. What are you eating? A stable isotope insight into the trophic ecology of short-beaked common dolphins in the Southwestern Atlantic Ocean. Mamm Biol 2016. [DOI: 10.1016/j.mambio.2016.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Riccialdelli L, Newsome SD, Fogel ML, Fernández DA. Trophic interactions and food web structure of a subantarctic marine food web in the Beagle Channel: Bahía Lapataia, Argentina. Polar Biol 2016. [DOI: 10.1007/s00300-016-2007-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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del Castillo DL, Segura V, Flores DA, Cappozzo HL. Cranial development and directional asymmetry in Commerson’s dolphin,Cephalorhynchus commersonii commersonii: 3D geometric morphometric approach. J Mammal 2016. [DOI: 10.1093/jmammal/gyw101] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Elemental concentrations in skin and internal tissues of Commerson’s dolphins (Cephalorhynchus commersonii) from subantarctic waters. Polar Biol 2016. [DOI: 10.1007/s00300-016-1962-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Andrade C, Ríos C, Gerdes D, Brey T. Trophic structure of shallow-water benthic communities in the sub-Antarctic Strait of Magellan. Polar Biol 2016. [DOI: 10.1007/s00300-016-1895-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Loizaga de Castro R, Saporiti F, Vales DG, García NA, Cardona L, Crespo EA. Feeding ecology of dusky dolphins
Lagenorhynchus obscurus
: evidence from stable isotopes. J Mammal 2015. [DOI: 10.1093/jmammal/gyv180] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
The dusky dolphin Lagenorhynchus obscurus occurs in the Southern Hemisphere, where it is restricted to coastal temperate areas. This study aimed to characterize the feeding ecology of dusky dolphins inhabiting northern and central Patagonia by using δ 13 C and δ 15 N stable isotope ratios in skin samples. We searched for evidence of geographical and seasonal variation in diet and we explored dietary differences between sexes. Significant differences in the stable isotope ratios of dusky dolphins were found among the 4 gulfs under study. Skin samples from Golfo San Matías and Golfo San Jorge were 13 C-enriched and 15 N-depleted compared to those from Golfo Nuevo and Golfo San José. There was no seasonality in the diet at Golfo Nuevo, and no differences in the diet between sexes in any gulf. Furthermore, Bayesian ellipses of males and females were similar in size and the overlap was mostly symmetrical in Golfo San José and Golfo San Jorge, while in the Golfo San Matías and Golfo Nuevo, females had wider ranges of δ 15 N, suggesting the exploitation of a wider trophic niche. Finally, pelagic fishes and demersal pelagic squids were identified as the main prey for this species of dolphin, although the proportion of each prey varied regionally.
El delfín oscuro Lagenorhynchus obscurus se distribuye ampliamente en el Hemisferio Sur, donde prefiere áreas templadas costeras. Este estudio tuvo como objetivo caracterizar la ecología trófica de delfines oscuros que habitan en el norte y centro de la Patagonia mediante el uso de isótopos estables de δ 13 C y δ 15 N en muestras de piel. Específicamente, buscamos evidencia de variación geográfica y estacional en la dieta de los delfines y exploramos la diferencia de dieta entre sexos. Se encontraron diferencias significativas en los valores de isótopos estables de los delfines entre los cuatro golfos bajo estudio. Las muestras de piel de Golfo San Matías y Golfo San Jorge se encuentran enriquecidas en 13 C y deprimidas en 15 N en comparación con las muestras del Golfo Nuevo y Golfo San José. No hubo estacionalidad en la dieta en el Golfo Nuevo, y no hay diferencias en la dieta entre sexos en ningún golfo. Además, las elipses bayesianas de machos y hembras fueron similares en tamaño y la superposición fue mayormente simétrica en el Golfo San José y el Golfo San Jorge, mientras que en el Golfo San Matías y el Golfo Nuevo, las hembras tienen rangos más amplios de δ 15 N, lo que sugiere la explotación de un nicho trófico más amplio. Por último, los peces pelágicos y los calamares demersales pelágicos fueron identificados como la presa principal de esta especie de delfín, aunque la contribución de cada presa varió regionalmente.
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Riccialdelli L, Goodall N. Intra-specific trophic variation in false killer whales (Pseudorca crassidens) from the southwestern South Atlantic Ocean through stable isotopes analysis. Mamm Biol 2015. [DOI: 10.1016/j.mambio.2015.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Rossman S, Ostrom PH, Stolen M, Barros NB, Gandhi H, Stricker CA, Wells RS. Individual specialization in the foraging habits of female bottlenose dolphins living in a trophically diverse and habitat rich estuary. Oecologia 2015; 178:415-25. [PMID: 25656585 DOI: 10.1007/s00442-015-3241-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/14/2015] [Indexed: 10/24/2022]
Abstract
We examine individual specialization in foraging habits (foraging habitat and trophic level) of female bottlenose dolphins (Tursiops truncatus) resident in Sarasota Bay, Florida, USA, by analyzing time series of stable isotope (δ(15)N and δ(13)C) values in sequential growth layer groups within teeth. The isotope data provide a chronology of foraging habits over the lifetime of the individual and allowed us to show that female bottlenose dolphins exhibit a high degree of individual specialization in both foraging habitat and trophic level. The foraging habits used by adult females are similar to those they used as calves and may be passed down from mother to calf through social learning. We also characterized the foraging habits and home range of each individual by constructing standard ellipses from isotope values and dolphin sightings data (latitude and longitude), respectively. These data show that Sarasota Bay bottlenose dolphins forage within a subset of the habitats in which they are observed. Moreover, females with similar observational standard ellipses often possessed different foraging specializations. Female bottlenose dolphins may demonstrate individual specialization in foraging habits because it reduces some of the cost of living in groups, such as competition for prey.
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Affiliation(s)
- Sam Rossman
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, USA,
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