Coupling spatio-temporal distribution to provide more informative population status and management recommendations

Accurate stock assessment (SA) is an essential basis to ensuring effective fisheries management. The trade-off between data input and output accuracy makes the surplus production model (SPM), which lacks spatial information, a widely used stock assessment model. We coupled species spatio-temporal distribution (STD) with SPM to better understand stock status and facilitate (targeted and spatially refined) fisheries management. In our coupled STD-SA framework, the spatio-temporal model not only provides accurate biomass index for the SPM, but also provides critical habitat assessments to better complement localized spatial information on stock status and factors contributing to the risk of population fluctuation. We demonstrated our framework with a commercially important fish population of Trichiurus lepturus in the Yellow Sea Large Marine Ecosystem (YSLME), which was once on the verge of population collapse. The results suggested that the population size has recovered to an acceptable level since 2017 and is currently in a healthy state (98.2% of probability). But the Bohai Sea still needs to be emphasized for conservation. The population can be further exploited; however, small portions of localized habitat still need to be focused on. Our framework can help to identify and implement targeted interventions to address localized stock fluctuation.