The extinction risk to populations of Sockeye or Red Salmon (Oncorhynchus nerka) is the focus of a PLoS ONE paper that was published today. The species’ global status is Least Concern on The IUCN Red List of Threatened Species™, but there is growing concern about the status of individual wild populations, particularly in the southern portion of the species’ range in North America. Salmon are a cultural and biological keystone of life throughout the Pacific Rim and play a unique role in linking freshwater and marine ecosystems.
The paper includes a description of changes made to a 2008 assessment of the species, which was completed by IUCN in late 2011. The assessment was conducted at both the species level and the population level. This new publication includes analysis at a finer spatial resolution, provides a more detailed accounting of threats specific to each population and explores both short term and long term population trends. The species exhibits a high degree of population diversity and local adaptation that allows existence in different environmental conditions.
Of the 98 independent populations identified, about one-third were data deficient, meaning there are sufficient data to determine status for about two-thirds of the populations. Of these, nearly one-third of the populations are at some level of risk and are considered threatened based on IUCN Red List criteria. Five populations are extinct. Results of the study underscore the need for continued conservation action. The greatest number and concentration of extinct and threatened populations are in the southern part of the north-temperate North American range. Specific causes of decline in certain populations continue to be debated, and the authors stress the need for additional research and monitoring to help pinpoint the local risks to wild salmon. Highlighted in the paper is an engaging, interactive web site, Visual Sockeye, to explore the intricacies of the assessment, and extend key conservation messages to a broader audience.
Sockeye Salmon adults typically display bright red bodies and green heads. They are mostly anadromous (swimming up rivers from the sea to spawn) and lay their eggs in gravel nests in rivers or lakes. Typically they live in freshwater habitats for up to three years before migrating to the ocean where they spend one to three years in offshore feeding areas. Once they have reached maturity (about 50-60cm in length and 2.5 to 3kg in weight) they migrate back to their natal freshwater habitat where they spawn and die. Many are captured by human fishers, seals, sea lion, and killer whales during the homeward spawning migration and by bears, eagles and gulls on the spawning grounds.
Salmon populations are exposed to many human threats, including overfishing, mixed-stock fisheries, habitat loss, habitat degradation, negative genetic and ecological interactions with hatchery fish, disease and parasites from fish farms. These threats operate at both the local and broad geographic scale, singularly or in various combinations and with varying degrees of intensity. Climate change is likely to increase risk to salmon in the future, particularly those already vulnerable in southern locations.
Reversing the declining trends will require innovative thinking and bold actions. The paper recommends the implementation of new wild salmon policies, restructuring coastal and river fisheries, adapting and reforming monitoring practices and initiating new research on those populations where data are insufficient.
The study represents unprecedented collaboration between the IUCN SSC Salmonid Specialist Group, the Pacific Salmon Commission, and government fisheries agencies, including Fisheries and Oceans Canada.
For more information, please contact:
Dr Pete Rand, Chair of the IUCN SSC Salmonid Specialist Group, email@example.com