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The common blue mussel ( Mytilus edulis ) was introduced to British Columbia, Canada, in the 1980s as an aquaculture alternative to native mussel species. Since then, the mussel industry in Pacific Canada has expanded and includes operations utilizing traditional methods of broodstock selection based on visual qualitative and quantitative traits. The impacts of hatchery propagation on genetic diversity and implications for animal fitness have been previously studied for other aquatic species, and this study further examines the effect of hatchery production on three M. edulis aquaculture populations in relation to a wild originator population. Prior to microsatellite genetic analysis, animals were identified to species using nuclear markers and were found to contain varying proportions of pure M. edulis as well as other pure species and hybrids from the ‘ Mytilus edulis complex’. Subsequently seven microsatellite markers were used to genotype 166 pure adult M. edulis individuals, all of which exhibited high levels of polymorphism. Allele frequencies at multiple loci did not conform to Hardy–Weinberg expectations and substantially less genetic diversity and very low effective population size estimates ( N e , calculated from linkage disequilibrium) were observed in farmed populations compared to the wild reference population. All populations were found to be genetically distinct based on F ST estimates. Mean allelic richness was approximately three times higher in the wild reference population than the three farmed populations (21 compared to 7.51, 7.91 in the two populations selecting for size and 8.24 in the population selecting for a colour morph). Observed heterozygosity was not significantly decreased in the cultured colour morph population, but was significantly different in the two other culture populations in comparison to the wild group. Reduced genetic diversity of the aquaculture populations is likely at least partially due to small effective breeding groups during hatchery propagation, creating genetic drift over successive generations. Speculations about the influence of broodstock selection practices are tentative and should be addressed in further temporal studies. These results indicate the need for the effective management of hatchery operations, the importance of rigorous site inventory, genetic broodstock characterization, and that ideally pedigree programs should be developed to help maintain healthy and productive shellfish culture populations with adaptive fitness capacity. Statement of relevance Hatchery methods impact species purity and genetic diversity. [ABSTRACT FROM AUTHOR]

Environmental impacts on fisheries are pervasive, yet methods to account for them in stock assessments and management decisions vary in rigour and quality. The prevalence and efficacy of methods to account for environmental impacts are not well documented, limiting our ability to adequately respond to future environmental and climate changes for adaptive resource management. In Canada, legislation now requires that environmental conditions are considered in the management of fish stocks, yet the current extent of implementation in assessment processes is poorly understood. We assessed the use of climate, oceanographic and ecological considerations in science advisory processes for 178 stock assessments by Fisheries and Oceans Canada. We evaluated whether these considerations were included in conceptual hypotheses about broad‐scale mechanisms, quantitative or qualitative analyses, and the development of management advice on current or future stock status. Conceptual hypotheses were included in 46% of assessments; quantitative inclusions occurred in 21% of assessments, while qualitative interpretations appeared in 31% of assessments; and 27% of assessments included climate, oceanographic and/or ecological considerations in the advice. Assessments of salmonids, invertebrates and pelagic taxa more frequently made use of environmental data than those for groundfish and elasmobranchs. Comparing our findings with assessments in other jurisdictions highlighted a gap in Canada's ability to respond to environmental changes and a need to develop integrated management approaches, such as regional ecosystem assessments and approaches that combine modelling and empirical analyses, with socio‐economic analysis within interdisciplinary teams. [ABSTRACT FROM AUTHOR]