Water temperature at the time of the catch-and-release event is a better predictor of survival in Atlantic salmon (Salmo salar) than acute water temperature changes before and after.

Despite studies on the effect of catch-and-release on the survival of Atlantic salmon (Salmo salar) being widespread in the literature, studies to date have failed to evaluate the potential role of thermal history. Herein, we show that despite cooler conditions post-release, 4/18 (22%) salmon died when caught-and-released at water temperatures ≥20°C, whereas 1/13 (8%) salmon caught-and-released at water temperatures ≤20°C, but who encountered mean water temperatures ≥20°C post-release, died. We conclude water temperature at time of the catch-and-release event remains the most suitable predictor of post-release survival.

Evidence of hatch-time based growth compensation in the early life history of two salmonid fishes.

Initial body size can indicate quality within-species, with large size increasing the likelihood of survival. However, some populations or individuals may have body size disadvantages due to spatial/temporal differences in temperature, photoperiod, or food. Across-populations, animals often have locally adapted physiology to compensate for relatively poor environmental influences on development and growth, while within-population individual behavioral adjustments can increase food intake after periods of deprivation and provide opportunities to catch up (growth compensation).

The Genomic Consistency of the Loss of Anadromy in an Arctic Fish ().

AbstractThe potentially significant genetic consequences associated with the loss of migratory capacity of diadromous fishes that have become landlocked in freshwater are poorly understood. Consistent selective pressures associated with freshwater residency may drive repeated differentiation both between allopatric landlocked and anadromous populations and within landlocked populations (resulting in sympatric morphs). Alternatively, the strong genetic drift anticipated in isolated landlocked populations could hinder consistent adaptation, limiting genetic parallelism.

Limited genetic parallelism underlies recent, repeated incipient speciation in geographically proximate populations of an Arctic fish (Salvelinus alpinus).

The genetic underpinnings of incipient speciation, including the genomic mechanisms which contribute to morphological and ecological differentiation and reproductive isolation, remain poorly understood. The repeated evolution of consistently, phenotypically distinct morphs of Arctic Charr (Salvelinus alpinus) within the Quaternary period offer an ideal model to study the repeatability of evolution at the genomic level. Sympatric morphs of Arctic Charr are found across this species' circumpolar distribution.

Extensive secondary contact among three glacial lineages of Arctic Char () in Labrador and Newfoundland.

Aim: The Pleistocene glaciation event prompted the allopatric divergence of multiple glacial lineages of Arctic char (), some of which have come into secondary contact upon their recolonization of the Holarctic. While three glacial lineages (Arctic, Atlantic, and Acadian) are known to have recolonized the western Atlantic, the degree of overlap of these three lineages is largely unknown. We sought to determine the distribution of these three glacial lineages in Labrador and Newfoundland at a fine spatial scale to assess their potential for introgression and their relative contribution to local fisheries.

A portrait of a sucker using landscape genetics: how colonization and life history undermine the idealized dendritic metapopulation.

Dendritic metapopulations have been attributed unique properties by in silico studies, including an elevated genetic diversity relative to a panmictic population of equal total size. These predictions have not been rigorously tested in nature, nor has there been full consideration of the interacting effects among contemporary landscape features, colonization history and life history traits of the target species. We tested for the effects of dendritic structure as well as the relative importance of life history, environmental barriers and historical colonization on the neutral genetic structure of a longnose sucker (Catostomus catostomus) metapopulation in the Kogaluk watershed of northern Labrador, Canada.

Microsatellite variation and genetic structure of brook trout (Salvelinus fontinalis) populations in Labrador and neighboring Atlantic Canada: evidence for ongoing gene flow and dual routes of post-Wisconsinan colonization.

In conservation genetics and management, it is important to understand the contribution of historical and contemporary processes to geographic patterns of genetic structure in order to characterize and preserve diversity. As part of a 10-year monitoring program by the Government of Newfoundland and Labrador, Canada, we measured the population genetic structure of the world's most northern native populations of brook trout (Salvelinus fontinalis) in Labrador to gather baseline data to facilitate monitoring of future impacts of the recently opened Trans-Labrador Highway. Six-locus microsatellite profiles were obtained from 1130 fish representing 32 populations from six local regions.