Occurrence of Lake Chub, Couesius plumbeus, in Northern Labrador

Lake Chub (Couesius plumbeus) were recently found in seven previously undocumented locations in northern Labrador. These populations represent the first recorded accounts of this species in the Labrador region north of the Churchill River drainage and east of the George River. Lake Chub likely invaded this region via dispersal routes provided by eastern spillways of glacial Lake Naskaupi

Using movement, diet, and genetic analyses to understand Arctic charr responses to ecosystem change

ACKNOWLEDGEMENTS The extensive datasets used in this study were reliant on the dedication and innovation of many residents of Nunatsiavut (Food Skills and Environmental Research Program), technicians and biologists from DFO (J. Seiden, D. Lancaster, M. Shears, M. Bloom, S. Duffy), the Nunatsiavut Government (P. McCarney, C. Andersen, L. Pijogge), Oceans North (S. Pain), and of the captains and crew of the What’s Happening and the Safe Passage. Suggestions by three anonymous reviewers also greatly improved the manuscript. Funding for this research was provided in part by ArcticNet and DFO Oceans.Peer reviewedPublisher PD

Trends in marine survival of Atlantic salmon populations in eastern Canada

Declines in wild Atlantic salmon (Salmo salar) abundance throughout the north Atlantic are primarily attributed to decreases in survival at sea. However, comparing trends in marine survival among populations is challenging as data on both migrating smolts and returning adults are sparse and models are difficult to parameterize due to their varied life histories. We fit a hierarchical Bayesian maturity schedule model to data from seven populations in eastern Canada to estimate numbers of out-migrating smolts, survival in the first and second year at sea, and the proportion returning after 1 year. Trends in survival at sea were not consistent among populations; we observe positive, negative, and no correlations in these, suggesting that large-scale patterns of changes in marine survival are not necessarily representative for individual populations. Variation in return abundances was mostly explained by marine survival in the first winter at sea in all but one population. However, variation in the other components were not negligible and their relative importance differed among populations. If salmon populations do not respond in a uniform manner to changing environmental conditions throughout their range, future research initiatives should explore why.publishedVersio

Model-based evaluation of the genetic impacts of farm-escaped Atlantic salmon on wild populations

Acknowledgements. The authors thank R. Gregory and T. Kess for comments on this manuscript. Funding was provided through the Fisheries and Oceans Program for Aquaculture Regulatory Research. This work has benefited greatly from a 3 year Canada-EU Galway Statement for the Transatlantic Ocean Research Alliance Working Group on modelling genetic interactions among wild and farm escaped Atlantic Salmon in the North Atlantic, involving participants from 7 countries. The models applied here were evaluated and discussed as part of this working group.Peer reviewedPublisher PD

Genetic mixed stock analysis of an interceptory Atlantic salmonfishery in the Northwest Atlantic

Interceptory fisheries represent an ongoing threat to migratory fish stocks particularly when managed in the absence of stock specific catch and exploitation information. Atlantic salmon from the southern portion of the North American range may be subject to exploitation in the commercial and recreational salmon fisheries occurring in the French territorial waters surrounding St. Pierre and Miquelon off southern Newfoundland. We evaluated stock composition of Atlantic salmon harvested in the St. Pierreand Miquelon Atlantic salmon fishery using genetic mixture analysis and individual assignment with a microsatellite baseline (15 loci, 12,409 individuals, 12 regional groups) encompassing the species western Atlantic range. Individual salmon were sampled from the St. Pierre and Miquelon fishery over four years (2004, 2011, 2013, and 2014). Biological characteristics indicate significant variation among years in the size and age distribution. Nonetheless, estimates of stock composition of the samples showed consistent dominance of three regions (i.e., Southern Gulf of St. Lawrence, Gaspe Peninsula, and New-foundland). Together salmon from these regions accounted for more than 70% of annual harvest over the decade examined. Comparison of individual assignments and biological characteristics revealed a trend of declining fresh water age with latitude of assigned region. Moreover, locally harvested Newfoundland salmon were ten times more likely to be small or one sea winter individuals whereas Quebec and Gaspe Peninsula salmon were two-three times more likely to be harvested as large or two sea winter salmon.Estimates of region specific catch were highest for salmon from the southern Gulf of St. Lawrence region ranging from 242 to 887 individuals annually. This work illustrates how genetic analysis of interceptory marine fisheries can directly inform assessment and management efforts in highly migratory marines pecies

Genomic evidence of recent European introgression into North American farmed and wild Atlantic salmon

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Genomic evidence of past and future climate-linked loss in a migratory Arctic fish

Acknowledgements We thank staff of the Newfoundland DFO Salmonids section, Parks Canada, the Nunatsiavut Government, the NunatuKavut Community Council, the Sivunivut Inuit Community Corporation, the Innu Nation, the Labrador Hunting and Fishing Association and fishers for their support, participation and tissue collections and the staff of the Aquatic Biotechnology Lab at the Bedford Institute of Oceanography for DNA extractions. This study was supported by the Ocean Frontier Institute, a Genomics Research and Development Initiative (GRDI) Grant, a Natural Sciences and Engineering Research Council (NSERC) Discovery Grant and Strategic Project Grant to I.R.B., the Weston Family Award for research at the Torngat Mountains Base Camp and an Atlantic Canada Opportunities Agency and Department of Tourism, Culture, Industry and Innovation grant allocated to the Labrador Institute. Author Correction: Layton, K.K.S., Snelgrove, P.V.R., Dempson, J.B. et al. Author Correction: Genomic evidence of past and future climate-linked loss in a migratory Arctic fish. Nat. Clim. Chang. 11, 551 (2021). https://doi.org/10.1038/s41558-021-01023-8Peer reviewedPostprin

Resolving fine-scale population structure and fishery exploitation using sequenced microsatellites in a northern fish

Funding Information Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Project Atlantic Canada Opportunities Agency and Department of Tourism, Culture, Industry and Innovation grants allocated to the Labrador Institute (MC) Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Genomics Research and Development Initiative (GRDI) Weston Family AwardPeer reviewedPublisher PD

Lepidurus arcticus (Crustacea : Notostraca); an unexpected prey of Arctic charr (Salvelinus alpinus) in a High Arctic river

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Data from: Transatlantic secondary contact in Atlantic salmon, comparing microsatellites, a SNP array, and Restriction Associated DNA sequencing for the resolution of complex spatial structure

Identification of discrete and unique assemblages of individuals or populations is central to the management of exploited species. Advances in population genomics provide new opportunities for re-evaluating existing conservation units but comparisons among approaches remain rare. We compare the utility of RAD-seq, a single nucleotide polymorphism (SNP) array and a microsatellite panel to resolve spatial structuring under a scenario of possible trans-Atlantic secondary contact in a threatened Atlantic Salmon, Salmo salar, population in southern Newfoundland. Bayesian clustering indentified two large groups subdividing the existing conservation unit and multivariate analyses indicated significant similarity in spatial structuring among the three data sets. mtDNA alleles diagnostic for European ancestry displayed increased frequency in southeastern Newfoundland and were correlated with spatial structure in all marker types. Evidence consistent with introgression among these two groups was present in both SNP data sets but not the microsatellite data. Asymmetry in the degree of introgression was also apparent in SNP data sets with evidence of gene flow towards the east or European type. This work highlights the utility of RAD-seq based approaches for the resolution of complex spatial patterns, resolves a region of trans-Atlantic secondary contact in Atlantic Salmon in Newfoundland and demonstrates the utility of multiple marker comparisons in identifying dynamics of introgression