Applying data-limited models (CMSY + + and LBB) to assess the stock status of Penaeus kerathurus (Forskål, 1775) in the Central Mediterranean (GSA 12)

Abstract

Abstract The Caramote prawn Penaeus kerathurus (Forskål, 1775) is a key species in the Mediterranean’s commercial fisheries, but up until now, its stock status in northern Tunisia (Geographical Sub-Area 12) is poorly understood. The present study provides a comprehensive evaluation of the species’ exploitation status in this region. It combines seasonal biological sampling ( individuals) from the Bizerte fishing port with two data-limited assessment models: CMSY , which was applied to catch data from 2006 to 2022, and Length-Based Bayesian Biomass Estimation (LBB), which used length-frequency distributions from 2024. As the relative biomass ( B / ) was estimated at 1.19 (CMSY ) and 2.30 (LBB), and the fishing mortality ( F / ) was below the sustainable threshold of 0.925 and 0.1, respectively, the results of both models thus indicated a healthy and underexploited stock. Seasonal size structures revealed a high proportion of mature individuals (>90%), with significant variations in mean total length across seasons (17.7-22.2 cm). The observed length at first capture (Lc = 14.7 cm) was close to the theoretical optimum (Lc opt = 15 cm), suggesting appropriate gear selectivity. Despite the favourable current situation, retrospective analysis highlighted historical instability in exploitation rates, emphasising the need for precautionary management. We recommend maintaining the current level of fishing effort, implementing seasonal spawning closures and improving regional monitoring to ensure long-term sustainability.