Temporal declines in fecundity: A study of southern Gulf of St. Lawrence Atlantic herring (Clupea harengus) and implications for potential reproductive output.

Individuals must reproduce to survive and thrive from generation to generation. In fish, the fecundity of individuals and estimates of total reproductive output are critical for evaluating reproductive success and understanding population dynamics. Estimating fecundity is an onerous task; therefore, many populations lack contemporary estimates of fecundity and size-fecundity relationships.

Adaptation to seasonal reproduction and environment-associated factors drive temporal and spatial differentiation in northwest Atlantic herring despite gene flow.

Understanding how marine organisms adapt to local environments is crucial for predicting how populations will respond to global climate change. The genomic basis, environmental factors and evolutionary processes involved in local adaptation are however not well understood. Here we use Atlantic herring, an abundant, migratory and widely distributed marine fish with substantial genomic resources, as a model organism to evaluate local adaptation.

Atlantic bluefin tuna diet variability in the southern Gulf of St. Lawrence, Canada.

The abundance of top predators in the southern Gulf of St. Lawrence, Canada, has fluctuated dramatically in recent decades. The associated increase in predation and its effect on the lack of recovery of many fish stocks in the system generates the need for a better understanding of predator-prey relationships and the implementation of an ecosystem approach to fisheries management.

Temporal stability and assignment power of adaptively divergent genomic regions between herring () seasonal spawning aggregations.

Atlantic herring (), a vital ecosystem component and target of the largest Northwest Atlantic pelagic fishery, undergo seasonal spawning migrations that result in elusive sympatric population structure. Herring spawn mostly in fall or spring, and genomic differentiation was recently detected between these groups. Here we used a subset of this differentiation, 66 single nucleotide polymorphisms (SNPs) to analyze the temporal dynamics of this local adaptation and the applicability of SNP subsets in stock assessment.

Intraspecific variation in thermal tolerance and acclimation capacity in brook trout (Salvelinus fontinalis): physiological implications for climate change.

Cold-water fishes are becoming increasingly vulnerable as changing thermal conditions threaten their future sustainability. Thermal stress and habitat loss from increasing water temperatures are expected to impact population viability, particularly for inland populations with limited adaptive resources. Although the long-term persistence of cold-adapted species will depend on their ability to cope with and adapt to changing thermal conditions, very little is known about the scope and variation of thermal tolerance within and among conspecific populations and evolutionary lineages.

Ice age fish in a warming world: minimal variation in thermal acclimation capacity among lake trout (Salvelinus namaycush) populations.

In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures.