Science Advisory Report 2018/017
The 2017 Fraser Sockeye Salmon (Oncorhynchus nerka) integrated biological status re-assessment under the Wild Salmon Policy
- This SAR reports on the first re-assessment of biological status under the Wild Salmon Policy (WSP). This work was completed for 24 Fraser Sockeye Salmon Conservation Units (CUs) in 2017, which updates the previous statuses for these CUs (DFO 2012).
- The status re-assessment process identified the following integrated statuses for Fraser Sockeye Salmon CUs (see Table 1 for CU descriptions and Table 2 for statuses):
- Seven Red; given the small distribution of the Widgeon-(river-type) CU, this CU will remain consistently Red; two Red/Amber; five Amber; six Amber/Green; three Green; and one data deficient.
- To enable status comparison for fisheries management applications, CUs were grouped into their four management groups: Early Stuart (EStu), Early Summer (ES), Summer (S), and Late (L). The status for the following CU’s changed from 2012 to 2017 (Tables 2 and 4):
- Status improved for six CUs: Nahatlatch-ES, Nadina-Francois-ES, Francois-Fraser-S, Chilliwack-ES, Anderson-Seton, and Pitt-ES.
- Status declined for six CUs: Harrison (upstream)-L, Shuswap-ES, Lillooet-Harrison-L, Harrison (downstream)-L, Seton-L, and Shuswap-L.
- Status did not change for 12 CUs:
- five CUs remained Red: Bowron-ES, Cultus-L, Takla-Trembleur-EStu, Taseko-ES, and Widgeon-(River-Type);
- two CUs remained Red/Amber: Quesnel-S and Takla-Trembleur-Stuart-S;
- two CUs remained Amber: North Barriere-ES and Kamloops-ES;
- two CUs remained Green: Chilko-S/Chilko-ES and Harrison-River Type;
- Chilko-ES remained data deficient.
- Consistent with past WSP status assessments, this 2017 process concluded that no single algorithm can be developed to integrate status. Therefore, expert judgment is required to integrate status across metrics and supporting information for each CU.
- For Fraser Sockeye Salmon cyclic CUs with stock-recruitment data, new Larkin-model derived abundance benchmarks were included in the status assessment process. Cyclic CUs are characterized by a repeating pattern of one very high abundance year, and three smaller years. For these CUs, density-dependent interactions between cycle lines is assumed. Cyclic CUs include: Shuswap-ES (i.e., Scotch and Seymour), Shuswap Complex-L, Chilliwack-ES, Takla-Trembleur-E St, Takla-Trembleur-Stuart-S, and Quesnel-S. Unique to cyclic CUs, abundance benchmarks and statuses are estimated for each of the four cycle lines. When applied in the expert-driven context, Larkin-model benchmarks for cyclic CUs are recommended for future status assessments.
- In addition to status designation, narratives on the factors that contributed to these statuses are provided for each CU (Table 3). The combination of CU statuses, data summaries, and narratives are recommended as inputs into the WSP Strategy 4 on Integrated Planning to guide recovery actions (CUs in Red to potentially Amber zones), and management actions (fisheries, salmonid enhancement, and habitat) that affect CUs in any status zone.
- This work demonstrates that re-assessment processes can be conducted with less effort (e.g. fewer than 9 individuals participating in a 1 day meeting for Fraser Sockeye Salmon), compared to first-time WSP status assessments (e.g. approximately 30 individuals over a 3 day meeting for Fraser Sockeye Salmon).
- It is recommended that data summaries be updated annually and that re-assessments be conducted every generation or when notable changes in CU productivity have occurred.
This Science Advisory Report is from the June 6 and 7, 2017 Fraser Sockeye Wild Salmon Policy Integrated Biological Status Re-Assessment. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada Science Advisory Schedule as they become available.
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