Research Document 2019/027

Recovery Potential Assessment for the Sakinaw Lake Sockeye Salmon (Oncorhynchus nerka) (2017)

By Ramshaw, B., Luedke, W, and Korman, J.

Abstract

Sakinaw Sockeye (Oncorhynchus nerka) was first assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as Endangered in an emergency assessment in 2002, which was confirmed in another assessment in 2003. The status was assessed in another emergency assessment and again confirmed as Endangered in 2006. For various reasons the species has never been listed on the Species at Risk Act (SARA). The species was reassessed by COSEWIC in 2016 and the status of Endangered was re-affirmed. Following the COSEWIC assessment in 2003 a national recovery strategy was developed. Although not formally endorsed by the Government of Canada, many of the recovery measures were undertaken to ensure survival or recovery of the species. The Recovery Potential Assessment (RPA) presented here provides the necessary background information, population status and mitigation options to advise a SARA listing decision. Sakinaw Sockeye experience a variety of threats and limiting factors throughout their life history. Predation of eggs, and predation during migration through Sakinaw Creek as smolts and returning adults, and during the early marine phase, is believed to be a limiting factor. Fry to smolt survival is low for hatchery fish (13%) and believed to be low (~19%) for wild fish, despite Sakinaw Lake being a very productive lake. Domestication due to the captive brood program is also a concern. The greatest limiting factor is very low marine survival (<0.5%), for which there are no clear mitigation measures. Population Viability Analysis (PVA) indicated that even a two fold increase in freshwater survival would not be sufficient to achieve recovery with current marine survival. Under current conditions, the survival of Sakinaw Sockeye requires human intervention through hatchery supplementation. Fisheries management plans implemented during the 1990s have been effective in reducing exploitation of Sakinaw Sockeye. The average exploitation rate for Sakinaw Sockeye was 5% from 2011 to 2015 and the PVA indicated that further decreasing exploitation would have no effect on increasing the probability of recovery. Given the high early life history stage mortality and the extremely low marine survival of Sakinaw Sockeye, minimum allowable harm should be permitted at this time, and be reduced below current levels of harm to the extent possible.

Research Document 2019/027 (PDF, 2,717 KB)

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