Climate change can compromise findings about the status of fish stocks from assessment models by causing changes in life-history parameters that go unrecognized. Assessments of fish stocks with data-poor methods are widely applied in fishery management and decision-making, but it is unclear how climate change may impact their findings. This study investigated the impact of temperature-driven change on the length-based assessment of stock status under different fishing mortality rates. We simulated the impact of temperatures on fifteen tropical and subtropical fish species that had a range of life-history strategies. We used a yield-per-recruit model and added temperature-dependence on the growth coefficient, and asymptotic length within and across the species’ geographic ranges. We then calculated how length indicators of the fishing mortality rate would diverge if temperature change caused unrecognized change in life-history parameters. Changes in length indicators depended on the location of a stock relative to its optimal temperature. Length indicators underestimated fishing mortality rate at the cool (high latitude) edge of the species’ range under warming, while overestimating it at the warm (low latitude) edge. However, for most species and at most temperatures, the sensitivity of length indicators to warming was small compared to the impact of changes in fishing mortality rate. Our framework can be used to identify species for which length indicators are most likely to be influenced by warming. We suggest caution is needed when interpreting length indicators for species near their latitudinal range edges in rapidly warming regions.
Takyi et al. (Tue,) studied this question.