Search

After the initial opening of the Bering Strait  5.5–-5.0 My ago, there occurred several periods with exchange of marine species between the Pacific and Atlantic Oceans. The snow crab (Chionoecetes opilio) was first reported in the Barents Sea (BAR) in 1996, presumably following introduction via Ballast water. Since then, the population has increased in size and distribution and has become self-reproducing and of economic importance. We implemented genetic analysis to identify the origin and pathway of introduction of BAR snow crab. Samples from BAR, Alaska, eastern Canada, and west Greenland were genotyped with 12 microsatellite loci. Pairwise F ST between 15 samples showed three geographic clusters, each significantly different from one another. Unexpectedly, the largest genetic distance was between the BAR and Greenland clusters. This clustering may be the result of dispersals through Bering Strait from the North Pacific Ocean and passage through the Arctic Ocean. The BAR samples did not show signs of a bottleneck in population size, as would be expected after introduction of small numbers of individuals. Presence of snow crab in the BAR may thus be the result of recent natural range expansion from around Alaska. [ABSTRACT FROM AUTHOR]

Deepwater redfish Sebastes mentella will be among the most important resource-sustaining commercial bottom-fish fisheries in the years to come in the Estuary and Gulf of St. Lawrence (EGSL). In 2011, 2012, and 2013, three strong cohorts were recruited to the stock; their abundance in 2018 was 80 times higher than that of the 1993–2012 period. The main goal of this work was to deepen our knowledge of their growth regulation and metabolism in order to identify molecular indicators and determine how they are influenced by natural environmental conditions. Fish weight and water temperature explained 11% of the variation in relative mRNA levels of specific gene targets in liver and muscle among seven sites where deepwater redfish were captured in the EGSL. The relative expression of liver insulin-like growth factor-1 (igf-1) and white muscle A-chain lactate dehydrogenase (ldh-a) correlate positively with weight, whereas heavy chain muscle myosin (myo), heart citrate synthase (cs), and white muscle pyruvate kinase (pk) correlate negatively. The relative expression of heart cytochrome c oxidase subunit 1 (cox-1) and white muscle igf-1 receptor isoform a (igf-1ra) correlate negatively with temperature. Deepwater redfish from the estuary were smaller than those caught at other sites. Since the growth potential of deepwater redfish was strongly correlated with temperature (being enhanced by higher temperatures), this study suggests an ecological advantage for this species in a climate-warming context. [ABSTRACT FROM AUTHOR]