Arctic Cod Boreogadus Saida Research Articles

Impact of mercury released from permafrost on food safety in Switzerland

ABSTRACT (ENGLISH) Climate change has caused the permafrost to thaw, releasing the previously sequestered mercury into the environment. Mercury has the ability to convert to methylmercury, a bioaccumulative neurotoxin. Exposure occurs in humans through the ingestion of contaminated food and it is associated with adverse health effects. In the context of global warming, this report aims to provide a basis for discussion on the impact of mercury released from permafrost on Switzerland's food safety. Data available in the scientific literature and in databases were reviewed in order to identify the relevant fish indicating the mercury exposure of the Swiss population and the potential evolution of the situation in the coming years. To assess the current relevance for Switzerland of undertaking mercury monitoring in indicator fish, gaps in the literature were identified. In addition, several experts were contacted regarding the topics described above in order to complement and refine the results of the literature review. The main results suggest that the current situation does not yet pose a threat to the Swiss population. However, mercury is certainly being released from the permafrost and its future impact remains uncertain at present. Two species provide some indication of the amount of mercury released by thawing permafrost: Atlantic cod Gadus morhua, one of the fish most imported into Switzerland from FAO zones 18, 21, 27 and 67, and Arctic cod Boreogadus saida because of its position in the Arctic food chain. To conclude, although fish is not a major component of the Swiss diet, it would be worthwhile to monitor the contamination of mercury in the two species mentioned above due to the uncertainty of the situation. It is not necessary for Switzerland to conduct its own chemical analyses of mercury in fish but it is important to regularly consult databases such as, the Arctic database(s) Seafood Data and to identify any possible increasing trend.

Acoustic researches of arctic cod <i>Boreogadus saida</i> (Gadidae) in the southwestern Chukchi Sea in 2003–2020

Spatial distribution patterns and abundance of arctic cod Boreogadus saida are considered for the southwestern Chukchi Sea on the data of acoustic surveys and trawl samples obtained by TINRO research vessels in 2003–2020. The highest abundance and biomass of this species indicated by the echosounder–measured backscattering coefficient sA (m2 per sq.n.mile) were observed in August 2003, decreased significantly in 2007–2008 and later, with the minimum in 2010, increased in 2014 due to the high portion of juveniles, but continued to decrease in recent years and reached the lowest value in 2020. This negative tendency for arctic cod contradicts to the walleye pollock abundance increasing in the southwestern Chukchi Sea on the background of warming in the Arctic. The arctic cod were distributed mainly in the northeastern and southwestern parts of the surveyed area, usually as vast fields of small schools or sparse layers. To the east from 174°W, the aggregations were formed by large-sized fish distributed mostly at the bottom. In the western area, the aggregations were formed within thermocline at the depth of 10–20 m or had two–layer structure with the juveniles dominated in the upper layer and larger fish at the bottom. Typical echograms showed dense schools of arctic cod with the height up to 30 m and horizontal size of 120–400 m, presumably formed by migrating fish. Diurnal vertical migrations were not expressed for this species, though the aggregations of lower density were observed at night, in general, with some local aggregations of permanently dense schools, both in the daytime and at night.

Marine fish of the Chaunskaya Bay — A shallow estuary of the East-Siberian Arctic

The Chaunskaya Bay, a large Arctic estuary with a surface of about nine thousand km 2, is poorly studied in terms of ichthyology, although there is a transit hub of the Northern Sea Route on its coast, the seaport of Pevek, and its southeastern coast is a part of the state natural reserve “Chaunskaya Guba”. Only 10 marine fish species have been recorded in the bay previously. The paper presents the results of studying fish (125 specimens from 20 stations) caught during the benthic survey at depths of 9–27 m in autumn 2020. The collections include demersal juveniles of 11 species from 7 families, 8 of which were recorded in the Chaunskaya Bay for the first time: Gymnocanthus tricuspis, Triglops pingelii, Aspidophoroides olrikii, Liparis tunicatus, Gymnelus barsukovi, Lycodes polaris, Lumpenus medius and Lumpenus fabricii. Juvenile Arctic cod Boreogadus saida, Artediellus scaber and Ammodytes hexapterus were also caught. L. fabricii and L. tunicatus were the most common species in catches, accounting for 65.6% of all individuals and 66% of the total biomass. The distribution of juvenile demersal fish across the bay’s water area is provided. The largest species diversity and the maximum fish abundance were recorded in the apex of the bay opposite the mouth of the Chaun River. Thus, 18 species of marine fish (excluding anadromous salmonids, whitefish and smelts) have been recorded from the Chaunskaya Bay in total.

Arctic cod (Boreogadus saida) hatching in the Hudson Bay system

Buoyant Arctic cod (Boreogadus saida) eggs are found at the surface or at the ice-water interface in winter. While winter temperatures in saline waters fall below 0°C, the temperature in areas affected by under-ice river plumes is slightly higher. Under-ice river plumes may therefore provide thermal refuges favoring the survival of the vulnerable early life stages of Arctic cod. Thermal refuges would allow early hatchers to survive, benefit from a long growing period, and add to the number of individuals recruiting to the adult population: These expectations define the freshwater winter refuge hypothesis. More than 42 rivers drain into Hudson Bay making it particularly well suited to test this hypothesis. Whereas the bulk of Arctic cod observed in Hudson Bay hatch between mid-April and June, some larvae hatch as early as January. We used two independent but complementary methods to test the hypothesis: (1) Lagrangian model simulations that traced back the planktonic trajectories of the sampled larvae and (2) measurements of the concentration of strontium-88 in the otolith cores. Throughout the Hudson Bay system, Lagrangian simulations revealed that early hatchers were more likely to hatch in lower surface salinities and that larvae reaching larger prewinter lengths were likely to have hatched near or within estuaries. Analysis of otolith microchemistry showed that larvae with low strontium-88 concentration in the otolith core, indicating a low salinity hatch location, had hatched earlier and thus had a longer growth period before freeze-up. These results show the potential for Arctic cod persistence in the Arctic where freshwater input is projected to increase and the ice regime is predicted to become more seasonal, provided that the surface temperatures remain below embryonic and larval lethal limits.

Effects of the timing of sea ice retreat on demersal fish assemblages in the northern bering and Chukchi Seas

The structure of demersal fish assemblages was investigated based on a total of 134 trawl samples collected in the northern Bering Sea (NBS) and Chukchi Sea (CS) during 12 summers between 1990 and 2013. In recent years, the timing of sea ice retreat has become earlier in the NBS. The present study was performed to clarify the environmental factors that contribute to the structure of demersal fish assemblages. Walleye pollock Gadus chalcogrammus were numerically dominant, followed by Bering flounder Hippoglossoides robustus and Arctic cod Boreogadus saida. Stations were classified into four major faunal assemblages by cluster analysis based on species density: I) boreal assemblages occurring southeast of St. Lawrence Island; II) stations dominated by Arctic species in the CS; III) stations with mixed Arctic and boreal species southwest of St. Lawrence Island; and IV) a less abundant assemblage limited to the north of Point Hope, comprising Arctic species. A permutation test revealed that, of the four physical parameters considered (i.e., bottom temperature, bottom depth, timing of sea ice retreat (TSR) and timing of sampling), TSR was the most prominent variable; it constituted 19.4% of the overall variance in species density and 57.7% of the variance explained by environmental factors. Multiple regression was applied to further analyze the factors that affected interannual changes in the densities of three zoogeographic types in the NBS. While TSR was the major factor that affected the density of Arctic species, variables that included bottom temperature were important for boreal species. These results suggest that mechanisms associated with sea ice conditions (i.e., annual-scale factors), rather than summer bottom temperature (i.e., short-term factors), influence the distribution of demersal fish assemblages in the NBS and CS.

Variation in the diet of beluga whales in response to changes in prey availability: insights on changes in the Beaufort Sea ecosystem

The eastern Beaufort Sea (EBS) beluga whaleDelphinapterus leucaspopulation has experienced a 20 yr decline in inferred growth rates of individuals, which is hypothesized to have resulted from changes in prey availability. We used fatty acid signatures and stable isotope ratios to reconstruct the proportional contributions of 14 prey species to the diets of 178 beluga whales from 2011 to 2014. Prey estimates using quantitative fatty acid signature analysis suggest that EBS beluga whales primarily consume Arctic codBoreogadus saida, a species highly sensitive to climate change. Prey estimates varied with year and sex and size class of the whales, with large males consuming the highest proportions of Arctic cod, and females consuming the highest proportions of capelinMallotus villosus. Estimated proportional contributions of Arctic cod to beluga diet decreased from 2011 to 2014, coinciding with an increase in capelin. Belugas consumed the highest proportions of capelin and the lowest proportions of cod in 2014, the same year in which body condition indices were lowest in the whales. We hypothesize that changing conditions in the Beaufort Sea ecosystem may result in a decreased consumption of Arctic cod by belugas and increased consumption of capelin, which may result in a decline in condition. This may predominately affect females and juveniles since they consume the highest proportions of capelin; however, long-term monitoring is needed for confirmation. Understanding inter-annual variation in prey, and the longer-term nutritional implications of shifting from an Arctic cod- to a capelin-dominated diet should be a priority for monitoring EBS predators.

Zooplankton Composition and Trophic Status of Aquatic Species in the Laptev and East Siberian Seas

The species composition, abundance, biomass, and distribution of zooplankton were studied on the shelf and slope of the northwestern Laptev Sea and the shelf of the East Siberian Sea in summer 2015. The trophic status of common zooplankton and fish species, as well as their position in the food webs of these two seas, has been determined based on stable carbon and nitrogen isotope analyses (δ13C and δ15N). Data of both stomach content and stable isotope analyses show significant age-related variations in the trophic status of the Arctic cod Boreogadus saida, which is the dominant fish species.

The Ensemble of Conformations of Antifreeze Glycoproteins (AFGP8): A Study Using Nuclear Magnetic Resonance Spectroscopy.

The primary sequence of antifreeze glycoproteins (AFGPs) is highly degenerate, consisting of multiple repeats of the same tripeptide, Ala–Ala–Thr*, in which Thr* is a glycosylated threonine with the disaccharide beta-d-galactosyl-(1,3)-alpha-N-acetyl-d-galactosamine. AFGPs seem to function as intrinsically disordered proteins, presenting challenges in determining their native structure. In this work, a different approach was used to elucidate the three-dimensional structure of AFGP8 from the Arctic cod Boreogadus saida and the Antarctic notothenioid Trematomus borchgrevinki. Dimethyl sulfoxide (DMSO), a non-native solvent, was used to make AFGP8 less dynamic in solution. Interestingly, DMSO induced a non-native structure, which could be determined via nuclear magnetic resonance (NMR) spectroscopy. The overall three-dimensional structures of the two AFGP8s from two different natural sources were different from a random coil ensemble, but their “compactness” was very similar, as deduced from NMR measurements. In addition to their similar compactness, the conserved motifs, Ala–Thr*–Pro–Ala and Ala–Thr*–Ala–Ala, present in both AFGP8s, seemed to have very similar three-dimensional structures, leading to a refined definition of local structural motifs. These local structural motifs allowed AFGPs to be considered functioning as effectors, making a transition from disordered to ordered upon binding to the ice surface. In addition, AFGPs could act as dynamic linkers, whereby a short segment folds into a structural motif, while the rest of the AFGPs could still be disordered, thus simultaneously interacting with bulk water molecules and the ice surface, preventing ice crystal growth.

Population Genetic Diversity of Arctic Cod (Boreogadus saida) of Russian Arctic Seas

We present the data on genetic variation of Arctic cod Boreogadus saida assessed using seven microsatellite loci in four samples collected in the Kara, Laptev, and East-Siberian seas in 2014 and 2017. We found small but mostly statistically significant differences between the samples. The estimates of spatial genetic differentiation of the Arctic cod in Russian Arctic seas (0.4% of the total genetic variation on average), similar to those for the rest of its panarctic distribution range, are the lowest among the related gadid species. However, significant temporal variability is noted in Arctic cod. The reasons for the weak spatial divergence of Arctic cod and the prospects for further population genetic studies are discussed.

New data on the diet of juvenile fish in the eastern Chukchi Sea

Data on feeding of underyearlings of arctic cod Boreogadus saida , pacific cod Gadus mac­rocephalus , saffron cod Eleginus gracilis , sand lance Ammodytes hexapterus , capelin Mallotus villosus , and other fish species were collected in the Chukchi Sea in August-September, 2017 in the framework of Arctic Integrated Ecosystem Survey (Arctic IES). In the time of survey, the eastern Chukchi Sea was free of the sea ice to 72о30′ N. Large aggregations of arctic cod were observed in the surveyed area. The diet of arctic cod juveniles and youngsters of other investi­gated species included both pelagic and near-bottom zooplankton, mainly copepods, euphausiids, oikoplevres, and juvenile decapods. The copepods Calanus glacialis and Calanus. hyperboreus dominated in the northern part of the surveyed area, being typical for the Arctic Ocean and Beau­fort Sea, and the species usual for the Bering Sea, as the copepods Calanus glacialis + Calanus marshallae , Eucalanus bungii , and Neocalanus cristatus , were in predominance in its southern part. Besides of these large-sized species, the species typical for the Alaska coastal waters were presented in the diet of juveniles, as the copepods Pseudocalanus spp., Centropages abdominalis , Acartia longiremis , Podon sp., Tortanus discaudatus , Epilabidocera amphitrites , and Eurytemora herdmani , as well as larvae of Polychaeta, Echinodermata, Cirripedia and veligers of Bivalvia. The arctic cod juveniles used the whole spectrum of prey but consumed mainly smalland medium-sized zooplankton, which biomass was relatively low in 2017: 21.8–243.5 mg/m3 in the southern part of the surveyed area and 5.1–83.0 mg/m3 in its northern part. Correspondingly, their feeding intensity was higher in the south: their stomach fullness was 98.7–67.5 ‱ in the south and 76.9–46.9 ‱ in the north; the mean daily ration was 4.2 % of the body weight in the south and 3.4 % in the north. These values are considered as low or medium, possibly the stock of arctic cod was too high for the feeding base, particularly in the northern area. From the other hand, the diets of arctic cod, saffron cod and sand lance were very similar in the areas of joint habitation, so competitive relations between these species could be assumed.

Ecology of Arctic cod Boreogadus saida (Gadiformes, Gadidae) and its fishery potential in Kara Sea

According to the bottom trawl-survey data, 97% of the ichthyomass in the southwestern region of the Kara Sea are composed of the Arctic cod Boreogadus saida; its stock is significantly higher than the previously registered resources. The Arctic cod is most unevenly distributed across the water area and capable to form the high-density aggregations, which can be caught by the targeted trawls. A wide range of the age composition (0+−6+), the size-age composition, and the growth rates of the Arctic cod in the trawl catches in the Kara Sea, which are different from those in the fish in the adjacent Barents Sea, can indicate their assignment of the Arctic cod in these seas to different populations.

Results of complex surveys in the East Siberian Sea in August 2015

Data on oceanographic conditions, composition of plankton communities, benthic and demersal fish and invertebrates in the southern East Siberian Sea are presented by results of the complex survey conducted in August 2015, The bottom trawl survey assessed 10 species of fish and 3 species of jellyfish with total biomass 1900 t. Arctic cod Boreogadus saida dominated absolutely in the benthic ichthyocenose (60.6 % of the total biomass). Besides, 3 species of shrimps, 1 crab species, 4 species of gastropods, and 6 other taxonomic groups of macrobenthos including starfish and isopods were found in trawl catches, with the average biomass of macrobenthos 41.7 kg/km 2 . In the bottom samples of macrobenthos, 12 taxonomic groups were presented, with predominance of bivalves, polychaetes, isopods, and amphipods (summary 95 % of the total biomass).

Laboratory rearing of wild Arctic cod Boreogadus saida from egg to adulthood.

The techniques and protocols used to successfully capture, transport and breed Arctic cod Boreogadus saida, as well as to rear their larvae through to adulthood are summarized. Breeding B. saida will increase the opportunity to study this fish species, which is a critical part of the Arctic food web.

Regional diving behavior of Pacific Arctic beluga whales Delphinapterus leucas and possible associations with prey

Two populations of beluga whales Delphinapterus leucas in the Pacific Arctic make seasonal migrations to regions characterized by diverse bathymetry and hydrography, yet there is limited information contrasting behavior and foraging across regions. We used satellite-linked timedepth recorders attached to 30 belugas from 1997 to 2012 to infer the depths at which belu- gas forage seasonally and regionally. We also examined the correspondence between patterns of beluga diving and the vertical distribution of a primary prey species, Arctic cod Boreogadus saida, within the western Beaufort Sea. A suite of regional diving metrics revealed that beluga dive behavior varied among regions and sometimes between populations. Estimates of occupancy time at depth, in addition to maximum and modal dive depths for 6 h periods, suggested that Eastern Chukchi Sea and Beaufort Sea belugas were regularly diving to the seafloor in shallow shelf regions. Along slope margins and in the deep Canada Basin (>3000 m), specific portions of the water column were more frequently targeted. The greatest maximum daily dive depths were >900 m in the Canada Basin. Arctic cod were most abundant at 200�300 m in the western Beaufort Sea, and beluga dives within the survey area also most frequently targeted these depths. These results are consistent with a hypothesis that Arctic cod are a primary prey item for Pacific Arctic belugas and suggest that foraging belugas dive to depths that maximize prey encounters. In the context of a rapidly transforming Arctic ecosystem increasingly exposed to anthropogenic activi- ties, our results quantify the ecological importance of key regions for these 2 populations.

Upper thermal limits of the hearts of Arctic cod Boreogadus saida: adults compared with larvae.

Wild adult and reared larval Boreogadus saida were acclimated to 3·5° C before testing their cardiac response to acute warming. Heart rate transition temperatures during warming were similar for adult and larval hearts, except that the maximum temperature for heart rate was 3° C warmer for adults. Thus, in a rapidly warming Arctic Ocean, the upper temperature limit for larval rather than adult B. saida appears more likely to dictate the southern range of the species.

Occurrence of a gelatinous predator (Cyanea capillata) may affect the distribution of Boreogadus saida, a key Arctic prey fish species

Although the Arctic cod (Boreogadus saida) has a pan-Arctic distribution, little is known about its occurrence in near-shore waters where this species is the principal prey for seabirds, marine mammals and other fish. Published research describes the scyphomedusa Cyanea capillata as an Arctic cod predator, and this paper presents observations from long-term investigations using active hydroacoustics that suggest the Arctic cod avoided C. capillata in two small bays of Cornwallis Island (Canadian High Arctic archipelago). Distribution patterns in echograms suggested that features such as boundary layer fronts restricted jellyfish movements and Arctic cod were often abundant on the side of fronts where C. capillata were absent. Thus, habitat partitioning allowed Arctic cod to share habitat with its predator, albeit exceptions to this sharing occurred when jellyfish abundance was high and Arctic cod were displaced. Thus, if a warmer Arctic triggers an increase in C. capillata abundance, it is possible that small-scale aspects of Arctic cod distribution could be affected. This in turn could have significant ripple effects within the Arctic food web, an additional and previously unrecognized consequence of climate change.

Seabird diet changes in northern Hudson Bay, 1981-2013, reflect the availability of schooling prey

Ongoing climate change is altering Arctic marine ecosystems with major conse- quences for food-webs. Seabirds, by foraging over large marine areas but returning regularly to their breeding colonies, provide a good medium for tracking such changes. We studied the prey delivered to nestling thick-billed murres Uria lomvia at a colony in northern Hudson Bay, Canada, over the period 1981−2013. During that period, ice conditions in the region altered substantially, with earlier break-up and clearance. This change was not gradual but mainly occurred in the mid- 1990s. Breeding chronology also advanced, but not as fast as early summer ice clearance advanced. Ice conditions strongly affected diet, presumably reflecting the change in the timing of breeding relative to ice clearance. Of the dominant species in the diet, the proportion of Arctic cod Boreogadus saida decreased and the proportion of capelin Mallotus villosus increased over the 33 yr period, even after ice effects were taken into account, suggesting a progressive and cumu- lative effect of environmental change on the marine community. Those cumulative changes were manifested primarily in the diet representation of the most frequent taxa (cod and capelin), with variation in secondary diet components being driven by the availability of the dominant taxa. Diet diversity, representing an increase in the proportion of benthic fish (stichaeids, zoarcids, pholids and sculpins) and invertebrates (squid, amphipods and crustaceans), increased when ice cover was low, and hatching was late relative to ice break-up. Chick growth rates were low when the proportion of benthic fish was high. Hence, although it appears that growth rates are influenced by diet composition, it is more likely that they reflect the availability of the dominant schooling prey species, rather than any nutritional deficiency in benthic species.

Upper thermal limits of cardiac function for Arctic cod Boreogadus saida, a key food web fish species in the Arctic Ocean.

The objective of this study was to determine the upper thermal limits of Arctic cod Boreogadus saida by measuring the response of maximum heart rate (f(Hmax)) to acute warming. One set of fish were tested in a field laboratory in Cambridge Bay (CB), Nunavut (north of the Arctic Circle), and a second set were tested after air transport to and 6 month temperature acclimation at the Vancouver Aquarium (VA) laboratory. In both sets of tests, with B. saida acclimated to 0° C, f(Hmax) increased during acute warming up to temperatures considerably higher than the acclimation temperature and the near-freezing Arctic temperatures in which they are routinely found. Indeed, f(Hmax) increased steadily between 0.5 and 5.5° C, with no significant difference between the CB and VA tests (P > 0.05) and with an overall mean ± s.e. Q10 of 2.4 ± 0.5. The first Arrhenius breakpoint temperature (T(AB)) for f(Hmax) was also statistically indistinguishable for the two sets of tests (mean ± s.e. 3.2 ± 0.3 and 3.6 ± 0.3° C), suggesting that the temperature optimum for B. saida could be reliably measured after live transport to a more southerly laboratory location. Continued warming above 5.5° C revealed a large variability among individuals in the upper thermal limits that triggered cardiac arrhythmia (T(arr)), ranging from 10.2 to 15.2° C with mean ± s.e. 12.4 ± 0.4° C (n = 11) for the field study. A difference did exist between the CB and VA breakpoint temperatures when the Q10 value decreased below 2 (the Q10 breakpoint temperature; T(QB)) at 8.0 and 5.5° C, respectively. These results suggest that factors, other than thermal tolerance and associated cardiac performance, may influence the realized distribution of B. saida within the Arctic Circle.

Temporal variation in western Hudson Bay ringed seal Phoca hispida diet in relation to environment

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 481:269-287 (2013) - DOI: https://doi.org/10.3354/meps10134 Temporal variation in western Hudson Bay ringed seal Phoca hispida diet in relation to environment Magaly Chambellant1,4,*, Ian Stirling2,3, Steven H. Ferguson1,4 1Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada 2Wildlife Research Division, Science and Technology Branch, Environment Canada, Edmonton, Alberta T6H 3S5, Canada 3Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada 4Fisheries and Oceans Canada, Winnipeg, Manitoba R3T 2N6, Canada *Email: mchambellant@yahoo.fr ABSTRACT: We present the first study of ringed seal Phoca hispida feeding habits in western Hudson Bay (WHB) using stomach content analysis and stable isotope analysis (SIA). Ringed seals were sampled during 9 Inuit subsistence harvests in Arviat, Nunavut, Canada, over the period 1991 to 2006. During the open-water season in summer and fall, ringed seals fed mostly on sand lance Ammodytes spp. In the spring, when annual sea ice was still present, Arctic cod Boreogadus saida and capelin Mallotus villosus were also important in the diet, and consumption of invertebrates was higher than in the open-water period. From SIA, adult ringed seals exploited slightly more benthic habitats than immature individuals. Sand lances were the main prey consumed throughout the study period, but strong interannual variation occurred. When break-up of the sea ice in spring was relatively late, as in the early 1990s, ringed seal consumption of sand lance and total energy input was lower than in subsequent years of the study, despite a higher importance of sculpins (Cottidae) in the diet. The consumption of other fish species changed in the 2000s: Arctic cod declined whereas capelin increased in importance. Our results suggest that ringed seals in WHB are sand lance specialists, and their population dynamics are, at times, strongly regulated by bottom-up processes. KEY WORDS: Bottom-up regulation · Feeding habit · Stable isotope · Stomach content · Index of global importance · Ammodytes spp. Full text in pdf format Supplementary material PreviousNextCite this article as: Chambellant M, Stirling I, Ferguson SH (2013) Temporal variation in western Hudson Bay ringed seal Phoca hispida diet in relation to environment. Mar Ecol Prog Ser 481:269-287. https://doi.org/10.3354/meps10134 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 481. Online publication date: May 07, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.

Composition and temporal variation in the diet of beluga whales, derived from stable isotopes

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 471:283-291 (2012) - DOI: https://doi.org/10.3354/meps10029 Composition and temporal variation in the diet of beluga whales, derived from stable isotopes Marianne Marcoux1,2,*, Bailey C. McMeans3, Aaron T. Fisk3, Steven H. Ferguson1 1Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada 2Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK 3Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada *Email: marianne.marcoux@gmail.com ABSTRACT: The diet of individuals within a species commonly differs among sex and age classes because of differences in energy requirements and physiological needs. Belugas Delphinapterus leucas show a high level of sexual habitat segregation and dimorphism that could result in differences in diet between the sexes. Here, we used stable isotopes of carbon (δ13C) and nitrogen (δ15N) from muscle and skin samples of 88 belugas, and likely prey species, to investigate how beluga diet in Cumberland Sound (Nunavut, Canada) varied between sexes, among age classes, and over time from 1982 to 2009. Based on linear mixed-effects models, older belugas had higher δ13C and δ15N than younger individuals of both sexes, suggesting that older individuals feed on more benthic, higher trophic-position prey than younger individuals. We also found a strong, decreasing trend in both δ13C and δ15N values over time, indicating either a temporal shift in beluga diet or an ecosystem-wide change in isotope values. Based on stable isotope mixing models performed on belugas sampled since 2000, both males and females fed primarily on Arctic cod Boreogadus saida and capelin Mallotus villosus. The latter is a recent invader to this ecosystem, which could explain the temporal shift in stable isotopes of the Cumberland Sound belugas. KEY WORDS: Marine mammal · Monodontidae · Arctic · Time series Full text in pdf format PreviousNextCite this article as: Marcoux M, McMeans BC, Fisk AT, Ferguson SH (2012) Composition and temporal variation in the diet of beluga whales, derived from stable isotopes. Mar Ecol Prog Ser 471:283-291. https://doi.org/10.3354/meps10029Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 471. Online publication date: December 19, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.