Abstract
Pot fisheries are a crucial component of small-scale fisheries worldwide, characterized by their low environmental impact, high species selectivity, and superior catch quality. However, these fisheries are often constrained by poor size selectivity, which results in substantial bycatch of juvenile target species and remains a major challenge for pot fisheries management globally. Incorporating escape gaps or increasing mesh size are effective technical measures to improve pot size selectivity and reduce the unintended capture of undersized individuals. However, the implementation of these measures typically depends on traditional experimental sea trials, which are costly, time-consuming, and restrict the number of gear designs that can be tested. This study focuses on the Chinese swimming crab (Portunus trituberculatus) pot fishery, which is the most economically important crab fishery along the Chinese coast. Laboratory experiments were conducted to establish predictive models for the size selectivity potential of swimming crab in pots. The size selectivity potential of a wide range of escape gap shapes and sizes, as well as mesh size and mesh opening angle, were investigated. The predictive models for the size selectivity potential were compared to earlier sea trial results and demonstrated their usefulness to predict swimming crab size selectivity. Based on these models, we provide guidelines to make swimming crab pot fishery size selective, which would contribute to the sustainable management of this pot fishery.