Research Document 2020/038
The 2017 Fraser Sockeye Salmon (Oncorhynchus nerka) Integrated Biological Status Re-Assessments Under the Wild Salmon Policy Using Standardized Metrics and Expert Judgment
By Grant, S.C.H., Holt, C.A., Pestal, G., Davis, B.M. and MacDonald, B.L.
Abstract
The first integrated biological status re-assessment under the Wild Salmon Policy (WSP) was completed for 24 Fraser Sockeye Conservation Units (CUs) in 2017. The first status assessment was conducted in 2012 (Grant et al. 2011; Grant and Pestal 2012), and this current status re-assessment adds five years of escapement data from 2011 to 2015 and recruitment data from the 2006 to 2010 brood years.
This re-assessment identified the following integrated statuses for Fraser Sockeye CUs:
- 7 Red
- 2 Red/Amber
- 5 Amber
- 6 Amber/Green
- 3 Green
- 1 data deficient
Eleven out of 24 CUs had the same status in the 2012 and 2017 assessments: five CUs remained in the Red status zone: Bowron-ES, Cultus-L, Takla-Trembleur-EStu, Taseko-ES, and Widgeon-(River-Type); two CUs each remained in the Red/Amber status zone: Quesnel-S & Takla-Trembleur-Stuart-S, the Amber status zone: North Barriere-ES and Kamloops-ES; and the Green status zone: Chilko-S/Chilko-ES aggregate and Harrison (River-Type).
Thirteen out of 24 CUs had different statuses between the 2012 and 2017 assessments. This demonstrates the need for re-assessments at least every five years. The status for six CUs declined to Red: Harrison (U/S)-L and Seton-L; or Amber: Shuswap-ES and Lillooet-Harrison-L; or Amber/Green: Harrison (D/S)-L and Shuswap-L. The status for seven CUs improved to Amber: Nahatlach-ES; Amber/Green: Nadina-Francois-ES, Chilliwack-ES, Francois-Fraser-S, and Anderson-Seton-ES; and Green: Pitt-ES. These differences emphasize that without regular re-assessments recovery actions cannot be appropriately prioritized.
In addition to providing status designations, narratives on the factors that contributed to these statuses are provided for each CU. The combination of CU statuses, data summaries, and narratives, are recommended as inputs into the WSP’s Strategy 4 on Integrated Planning. As a package, this information can guide recovery actions among the Red to Amber CUs, and also guide management actions (fisheries, salmonid enhancement, and habitat) that affect all CUs.
This status re-assessment process demonstrated that re-assessments can be conducted on a smaller scale (<9 individuals in a 1 day plenary session) than first-time WSP status assessments (~30 individuals over a 3 day plenary session in the case of Fraser Sockeye).
Similar to past status assessments, the current assessment also concludes that no single algorithm for status integration can be developed, since CUs with the same status, will not always have the same factors that drive their status designations. Instead, expert-judgement applied consistently to assess WSP status is recommended.
The current process also had recommendations for particular metrics applied. The three-generation-trend metric, relied upon by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and the International Union for Conservation of Nature (IUCN) for their status evaluations, was considered less applicable to Pacific Salmon in WSP integrated status processes. New relative-abundance benchmarks, derived from the Larkin model, were included in the status assessment process for cyclic Fraser Sockeye CUs. The six cyclic CUs include Shuswap-ES, Shuswap-L, Takla-Trembleur-Early Stuart, Takla-Trembleur-Stuart-S, and Quesnel, and Chilliwack-ES. When applied in this expert-driven context, Larkin-model benchmarks are recommended for future status assessment processes for cyclic CUs.
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