Global Assessment of Extinction Risk to Populations of Sockeye Salmon Oncorhynchus nerka

Abstract

BackgroundConcern about the decline of wild salmon has attracted the attention of the International Union for the Conservation of Nature (IUCN). The IUCN applies quantitative criteria to assess risk of extinction and publishes its results on the Red List of Threatened Species. However, the focus is on the species level and thus may fail to show the risk to populations. The IUCN has adapted their criteria to apply to populations but there exist few examples of this type of assessment. We assessed the status of sockeye salmon Oncorhynchus nerka as a model for application of the IUCN population-level assessments and to provide the first global assessment of the status of an anadromous Pacific salmon.Methods/Principal FindingsWe found from demographic data that the sockeye salmon species is not presently at risk of extinction. We identified 98 independent populations with varying levels of risk within the species' range. Of these, 5 (5%) are already extinct. We analyzed the risk for 62 out of 93 extant populations (67%) and found that 17 of these (27%) are at risk of extinction. The greatest number and concentration of extinct and threatened populations is in the southern part of the North American range, primarily due to overfishing, freshwater habitat loss, dams, hatcheries, and changing ocean conditions.Conclusions/SignificanceAlthough sockeye salmon are not at risk at the species-level, about one-third of the populations that we analyzed are at risk or already extinct. Without an understanding of risk to biodiversity at the level of populations, the biodiversity loss in salmon would be greatly underrepresented on the Red List. We urge government, conservation organizations, scientists and the public to recognize this limitation of the Red List. We also urge recognition that about one-third of sockeye salmon global population diversity is at risk of extinction or already extinct.

Postsmolt Growth and Thermal Regime Define the Marine Survival of Steelhead from the Keogh River, British Columbia

“…Experimental tests of this theory, however, found no evidence that higher ultraviolet exposure resulted in higher mortality rates in either the freshwater phase or the early marine phase (Melnychuk et al 2012). Climate helps to define the suitability of freshwater habitats, with limits usually delineated by latitudinal ranges: for example, in the Northern Hemisphere, warming climate conditions will open new habitats at higher latitudes and will make other habitats at lower latitudes unsuitable over time (Rand et al 2012). However, this aspect of climate forcing does not match the pattern of recruitment coherence seen in Pacific salmon, particularly steelhead, over time Smith et al 2000;Welch et al 2000).…”

Understanding Smolt Survival Trends in Sockeye Salmon

“…Global abundances are driven primarily by Pink Salmon O. gorbuscha and Chum Salmon O. keta, as well as, particularly in the eastern North Pacific Ocean, by Sockeye Salmon O. nerka (Eggers 2009;Ruggerone et al 2010;Irvine and Fukuwaka 2011). The status of Sockeye Salmon populations varies among regions however, and in British Columbia's Fraser River, low Subject editor: Suam Kim, Pukyong National University, Busan, South Korea *Corresponding author: james.irvine@dfo-mpo.gc.ca Received February 8, 2013; accepted July 24, 2013 numbers of returning salmon in recent years are a major concern (Grant et al 2011;Rand et al 2012).The Fraser River watershed is one of the world's greatest salmon producers (Northcote and Larkin 1989), although numbers returning annually are highly variable. Sockeye Salmon are the most economically valuable salmon species in the watershed, and have provided a commercial harvest since the early 1870s (Meggs 1991) (Cohen 2012a(Cohen , 2012b(Cohen , 2012c.…”

Distinguishing benchmarks of biological status from management reference points: A case study on Pacific salmon in Canada

“…We demonstrate the distinction between biological benchmarks and management reference points with a case study on wild Pacific salmon in Canada, a multi-species resource of significant economic and social value (Bottom et al 2009;Wild Salmon Center 2009) that has recently attracted attention due to conservation concerns about various populations (see Peterman & Dorner 2012;Rand et al 2012). We provide the example of sockeye salmon from the Fraser River to illustrate the independent processes of developing biological benchmarks and reference points for management, and how uncertainties are explicitly considered in the determination of both.…”