A risk table to address concerns external to stock assessments when developing fisheries harvest recommendations

Figures & data

Figure 1. Harvest control rule for NPFMC Tier 3 stocks where F35% is considered a proxy for FMSY showing the buffer between the ABC and OFL, and how fishing mortality is ramped downwards as stock size declines.

Table 1. Risk classification table for assessment, population dynamics, and environmental/ecosystem considerations.

	Assessment-related considerations	Population dynamics considerations	Environmental/ecosystem considerations
Level 1: Normal	Typical to moderately increased uncertainty; minor unresolved issues in assessment.	Stock trends are typical for the stock; recent recruitment is within normal range.	No apparent environmental/ecosystem concerns.
Level 2: Substantially increased concerns	Substantially increased assessment uncertainty or unresolved issues.	Stock trends are unusual; abundance increasing or decreasing faster than has been seen recently, or recruitment pattern is atypical.	Some indicators showing an adverse signals but the pattern is not consistent across all indicators.
Level 3: Major Concern	Major problems with the stock assessment; very poor fits to data; high level of uncertainty; strong retrospective bias.	Stock trends are highly unusual; very rapid changes in stock abundance, or highly atypical recruitment patterns.	Multiple indicators showing consistent adverse signals a) across the same trophic level, and/or b) up or down trophic levels (i.e., predators and prey of stock)
Level 4: Extreme concern	Severe problems with the stock assessment; severe retrospective bias. Assessment considered unreliable.	Stock trends are unprecedented. More rapid changes in stock abundance than have ever been seen previously, or a very long stretch of poor recruitment compared to previous patterns.	Extreme anomalies in multiple ecosystem indicators that are highly likely to impact the stock. Potential for cascading effects on other ecosystem components.

Figure 2. Flow of ecosystem information in NPFMC annual harvest specification process. Risk tables are produced for each stock assessment using information from both the ecosystem-level ecosystem status report (ESR) and from the stock-specific ecosystem and socio-economic profiles (ESP).

Table 2. Risk table evaluation for Gulf of Alaska pollock in the 2018 stock assessment.

Assessment-related considerations	Population dynamics considerations	Environmental/ecosystem considerations
Contradictory data, very poor model fits to recent survey indices. But model seems robust, no retrospective pattern. Conclusion: Level 2, substantially increased concerns	Stock dominated by a single year class. Four years of very weak recruitment. There have been similar patterns in the past, but never this extreme. Conclusion: Level 2, substantially increased concerns	Onset of a marine heatwave and projections of a weak El Niño are not conducive for winter survival for age-0 pollock. Zooplankton indicators are mixed. Some suggest prey for adult pollock is abundant, but planktivorous parakeet auklets in the central GOA had poor reproductive success in 2018. Conclusion: Level 2, substantially increased concerns