Search

The occurrence of the invasive pink salmon (Oncorhynchus gorbuscha, Walbaum 1792) in Greenland was initially described in 2019 using social media to collect data on their presence. In this study we continue data collection through social media and initiate a monitoring program of the Kapisillit River in Southwest Greenland using snorkeling and environmental DNA (eDNA) metabarcoding in 2020 and 2021. The Kapisillit River is the only freshwater system in Greenland, where the red-listed Atlantic salmon (Salmo salar, Linnaeus 1758) is known to spawn. This genetically unique population of Atlantic salmon has been found to decline, wherefore there is general conservation concern that the occurrence of pink salmon at some point can become an additional stressor to the “Kapisillit salmon”. In 2021, pink salmon were present near all larger populated areas in Greenland and likely more abundant than in 2019. From visual observations and using eDNA, the presence of pink salmon was documented in the Kapisillit River in 2021. From the number of individuals observed combined with the spatial distribution of eDNA detections in the river, we suggest that the pink salmon invasion in the Kapisillit River is at an early stage.

Kangirsuk, is an Inuit community of Nunavik (Qc, Canada), renowned for the abundance of its anadromous Arctic char (Salvelinus alpinus), which are also a livelihood resource for the local population. However, near the community, char temporarily disappear from Lake Tasirjuarusik during the winter, only to reappear in the spring. The local association of hunters and fishermen (Anguvigaq) wanted to elucidate this mysterious disappearance by telemetry monitoring. This paper describes the process followed to build a collaborative research project between Inuit and non-Inuit scientists, from the funding application to the first fieldwork. The project is led by Inuit partners, Kangirsuk local association of hunters and fishers (Anguvigaq), in collaboration with scientific partners. The approach presented is intended to be an example of a collaborative project in indigenous territory that can be replicated and that promotes the commitment of all the collaborators, Inuit and non-Inuit.

Although intestinal microbial communities from anadromous Arctic char (Salvelinus alpinus (Linnaeus, 1758)) in Kitikmeot, Nunavut, Canada, differ depending on the timing and location of capture, determinants of gut microbiota in other wild Arctic salmonids are largely unknown. Using high-throughput 16S rRNA gene sequence data, we compared intestinal microbiota from Arctic char to those from a related and sympatric salmonid, lake whitefish (Coregonus clupeaformis (Mitchill, 1818)). Shifts in lake whitefish gut microbial community composition were observed between brackish water and freshwater, similar to impacts of salinity reported previously for Arctic char. Despite these similarities, gut community profiles for the two salmonids differed, with whitefish having higher diversities and increased proportions of taxa affiliated with potential pathogens. Geography seemed to have a greater impact on freshwater whitefish gut microbiota than on corresponding Arctic char. Additionally, microbiota diversity was significantly more affected by feeding behavior in whitefish compared with sympatric Arctic char. As sampled whitefish were at their northern range limits and grew slowly, we speculate that they, and their microbial consortia, could be more vulnerable to certain abiotic and biotic factors than Arctic char, which are well adapted to conditions found in these high latitude environments and have the most northern distribution of any freshwater fish.

The lake ecology of high-latitude fishes is strongly influenced by seasonal feeding opportunities and environmental stochasticity in Arctic environments. Arctic Charr (Salvelinus alpinus (Linnaeus, 1758)) populations are prevalent throughout the Arctic and show multiple life history strategies across their range. Unlike Old World populations, the lake ecology of Arctic Charr populations on south Baffin Island remains poorly defined. We examined the comparative seasonal lake ecology of two differing Arctic Charr populations (anadromous and landlocked) in Cumberland Sound, Nunavut. Anadromous Charr showed no evidence of feeding occurring within freshwater once they began seaward migrations. Anadromous Charr achieve sexual maturation at a larger size and younger age than landlocked Charr. Landlocked Charr used more lake habitats than anadromous Charr with feeding opportunities as an apparent influence on habitat selection. Landlocked Charr fed year round. They adopted a cannibalistic feeding strategy in the winter but consumed a variety of prey items in the fall. Littoral habitat was found to be important to all sizes of Charr in both seasons. Smaller anadromous Charr (

Climate change is having myriad effects on Arctic marine ecosystems and food webs. Anadromous Arctic Char, Salvelinus alpinus (Linnaeus, 1758), feed intensively at sea during summer. In Cumberland Sound, Nunavut, Canada, there has been a recent increased availability of a forage fish, Capelin. To investigate changes over time in Arctic Char foraging, we assessed Arctic Char trophic niche from 2002 to 2011 using stomach content analysis and stable isotope analysis (δ13C and δ15N) of muscle tissue from two river/lake systems, Isuituq and Kipisa. We also compared population characteristics by calculating Fulton’s condition factor (K) and by fitting von Bertalanffy growth curves with length-at-age data. Results revealed Capelin were newly present in the diets of Arctic Char in 2011, describing a shift from a primarily invertebrate-based to a fish-based diet. No trend in δ15N over time suggests that the trophic level of Arctic Char has not changed; however, the δ15C for both systems converged in 2011 on a value suggestive of feeding on Capelin. Growth curves and length-at-age analyses suggest that foraging on Capelin may have increased individual growth. Changes in the growth and condition of Arctic Char in this region could have significant economic and cultural implications.

Throughout their range, anadromous Arctic Char (Salvelinus alpinus (Linnaeus, 1758)) support commercial, recreational, and subsistence fisheries that are important economically, socially, and culturally. However, drivers of interannual variation in survival in this species remain poorly understood. Here, we aimed to quantify the impact of environmental and biological parameters on the survival probability of anadromous Arctic Char near the community of Cambridge Bay, Nunavut, Canada. To do so, we tracked 183 Arctic Char tagged with acoustic transmitters and used capture–mark–recapture methods to estimate survival probabilities over six years. Annual survival probabilities for individuals was high, varying between 0.79 and 0.88, whereas recapture probabilities varied between 0.64 and 0.90. Interannual variation in survival probability was low and neither the environmental (air temperature and sea ice cover) nor biological (sex) variables influenced survival probability. These estimates suggest that annual survival probability is high for anadromous adult Arctic Char in the Cambridge Bay area, despite clear differences in the ice cover melt date among years. These results further our understanding of the demographic parameters of Arctic Char in the region, which will be important for future assessments of the sustainability of commercial fisheries as well as for predicting population responses to a rapidly changing Arctic.

We analyzed Arctic char (Salvelinus alpinus (Linnaeus, 1758)) stable isotope ratios and fatty acid composition from two geographically proximal Nunavut lakes, Qasigiyat and Iqalugaarjuit, to determine if anadromous and resident Arctic char occupied different trophic niches. Resident Arctic char had lower δ13C and δ34S, indicative of freshwater feeding, compared with anadromous individuals. Significantly lower δ15N of residents suggests the ecotypes feed at different trophic levels. Significantly wider δ13C and δ15N ranges in residents implied a broader trophic niche or a wider range in baseline prey isotope values. Results also provide further evidence for resident use of the estuarine environment in Qasigiyat. Immature Arctic char occupy a different trophic niche than both resident and anadromous fish within Iqalugaarjuit, but this relationship is less clear in Qasigiyat. Distinct stable isotope and fatty acid profiles indicate that resident and anadromous Arctic char have distinct trophic niches: marine for anadromous, freshwater for resident. Immature Arctic char seem to occupy a distinct niche from both anadromous and resident fish, which likely relates to use of both freshwater and estuarine environments, depending on developmental stage. We show the first evidence of the fatty acid differences and niche segregation between sympatric anadromous and resident ecotypes in Arctic char.