Discussion: Should the Dams Be Removed to Save the Pacific Northwestern Salmon Population?

From 1885 till now, dams keep played an important role in Pacific Northwest. However, despite providing transportation convenience and electricity affecting the salmon population, they greatly impacted the salmon population. Nowadays, people standing for different parties are arguing whether the dams should be removed to restore the salmon population. Currently, a solid plan for dam removal has been proposed by Congressman Simpson. And it’s barely a start, further discussions will become more intensified and require an urgent environmental political response.

A comparison of trends in population size and life history features of Atlantic salmon (Salmo salar) and anadromous and non-anadromous Brown trout (Salmo trutta) in a single catchment over 116 years

We use a long time series of catch abundance from a recreational fishery over 116 years to look for population trends in Atlantic salmon, and anadromous (sea trout) and non-anadromous (brown) trout for a single catchment, Loch Lomond, west central Scotland. Year strongly predicted variation in catches but catch effort did not meaningfully increase explained variation. Salmon showed periods of increasing and decreasing trends, for sea trout and brown trout there was an overall declining trend. Since 1952, Lomond salmon population trends differed from both wider Scotland and southern Europe, indicating that the Lomond population is partially buffered from drivers of change in salmon populations more widely. In contrast Lomond sea trout showed a similar declining trend to that of populations from the wider west of Scotland over this period. The Lomond populations showed some evidence of shorter-term cycling patterns; the drivers for which are unknown. Body size in salmon and sea trout declined but increased in brown trout; salmon returned to freshwater later, and the relative proportion of all caught trout that were anadromous increased across the time series. This study shows a long and protracted period of fundamental change to populations of these two species over 116 years.

Genetic Relationship and Structural Analysis of Resident Pacific Salmon Oncorhynchus Masou in Mijiang River, China

Masu salmon Oncorhynchus masou has been listed as national second-class protected species in China, and many of its local populations have been under threats of decline because of environmental deterioration by human activity, such as habitat loss, water pollution, or dams. Genetic characteristics should be clarified in wild masu salmon population for an effective protection and recovery. In the present study, we explained genetic relationship and structure of masu salmon population in Mijaing River by sequencing the COI gene and analyzing microsatellite makers. Results of COI sequences analysis revealed 15 gene variable sites in approximately 696 bp, which defined 12 haplotypes, including some haplotypes related to geographic regions. The NJ tree indicated genetic relationship that we preliminarily inferred, that is, the masu salmon from Mijiang River belonged to the cherry salmon family (O. masoumasou). Results based on 14 microsatellite loci showed high haplotype diversity and low nucleotide diversity, indicating low genetic diversity of wild masu population in Mijaing River. The observed genetic structure was influenced primarily by bottlenecks due to overfishing and habitat loss. Since masu salmon has become highly vulnerable in China, we recommend to strengthen the protection of resident masu salmon population.

An Indigenous food sovereignty initiative is positively associated with well-being and cultural connectedness in a survey of Syilx Okanagan adults in British Columbia, Canada

Background For the Syilx Okanagan Nation in Canada, salmon has vital nutritional, cultural, and spiritual significance. Yet, the Okanagan Sockeye salmon population came to near extinction, resulting in a drastic decline in salmon consumption from high historical levels. Thus, restoring and protecting salmon is crucial to Syilx well-being and way of life. A Syilx-led food sovereignty initiative re-established the Okanagan Sockeye salmon population, which has resulted in a rise in fish harvesting. The aim of this study was to assess whether engaging with this initiative was associated with health, well-being, and cultural connectedness (i.e., degree to which one is integrated in their culture) among Syilx adults. Eating Okanagan Sockeye salmon was conceptualized as a proxy for engaging with this Indigenous food sovereignty initiative. Methods 265 Syilx adults completed a survey including a traditional food frequency questionnaire and questions on health status (e.g., BMI, self-assessed physical health), well-being (e.g., life satisfaction, stress levels), and cultural connectedness (e.g., sense of belonging, importance of cultural practices). Participants were divided into 3 groups based on their wild salmon eating during the year prior to the survey: (1) adults who ate Okanagan Sockeye salmon, (2) adults who ate salmon but did not usually know the species of the salmon they ate, or who solely ate salmon that were not Okanagan Sockeye; and (3) adults who did not eat any salmon. Results A statistically significant gradient was observed for enhanced well-being and cultural connectedness, with individuals in group 1 having better indicators than those in group 2, and adults in groups 1 and 2 having better indicators than adults in group 3. No differences were observed in physical health outcomes between the three groups. Conclusion Findings suggest that the initiative to re-establish Okanagan Sockeye salmon in the Okanagan River system may have led to better well-being and cultural connectedness among Syilx adults. This study highlights the importance of Indigenous food sovereignty as a way to enhance well-being and cultural connectedness among First Nations in Canada. Findings also reinforce the importance of assessing health and well-being in a wholistic way in Indigenous health research.

Redefining the oceanic distribution of Atlantic salmon

Determining the mechanisms driving range-wide reductions in Atlantic salmon marine survival is hindered by an insufficient understanding of their oceanic ecology and distribution. We attached 204 pop-up satellite archival tags to post-spawned salmon when they migrated to the ocean from seven European areas and maiden North American salmon captured at sea at West Greenland. Individuals migrated further north and east than previously reported and displayed increased diving activity near oceanographic fronts, emphasizing the importance of these regions as feeding areas. The oceanic distribution differed among individuals and populations, but overlapped more between geographically proximate than distant populations. Dissimilarities in distribution likely contribute to variation in growth and survival within and among populations due to spatio-temporal differences in environmental conditions. Climate-induced changes in oceanographic conditions will alter the location of frontal areas and may have stock-specific effects on Atlantic salmon population dynamics, likely having the largest impacts on southern populations.

Every cog and wheel: Unraveling biocomplexity at the genomic and phenotypic level in a population complex of Chinook salmon

Genomic diversity is the fundamental building block of biodiversity and the necessary ingredient for adaptation. Our rapidly increasing ability to quantify functional, compositional, and structural genomic diversity of populations forces the question of how to balance conservation goals – should the focus be on important functional diversity and key life history traits or on maximizing genomic diversity as a whole? Specifically, the intra-specific diversity (biocomplexity) comprised of phenotypic and genetic variation can determine the ability of a population to respond to changing environmental conditions. Here, we explore the biocomplexity of California’s Central Valley Chinook salmon population complex at a genomic level. Notably, despite apparent gene flow among individuals of different migration (life history) phenotypes inhabiting the same tributaries, each group is characterized by a component of unique genomic diversity. Our results emphasize the importance of formulating conservation goals focused on maintaining biocomplexity at both the phenotypic and genotypic level. Doing so will maintain the adaptive potential to increase the probability of persistence of the population complex despite changing environmental pressures.

Environmental and genetic influences on fitness-related traits in a hatchery coho salmon population.

Many natural and managed organisms will require substantial functional genetic variation to respond to selection in the face of rapid environmental change. Pacific salmon have experienced strong fluctuations in critical fitness traits over the past five decades. We examined genetic and phenotypic variability over three generations in a pedigreed hatchery population of coho salmon (Oncorhynchus kisutch) by monitoring seven fitness-related traits. Three-year-old adult return numbers varied more than five-fold, and jack (2-year old males) numbers varied 13-fold. Body sizes of Inch Creek coho salmon decreased consistently such that fish were only 40.7% as heavy in 2015 as in 2006 and female reproductive traits also decreased. During the study period, the majority of families produced returning adult progeny and effective population size was relatively constant. Heritability estimates for phenotypic traits were significantly greater than zero except for condition factor, and the estimated heritability for jacking was 0.42. The Inch Creek coho salmon population harbours substantial heritability for fitness and reproductive traits and thus likely retains significant capacity for adaptation despite many years of hatchery propagation.