Applying CMSY and BSM to Estimate Stock Status and Biological Reference Points of the Nile Tilapia and African Catfish Fisheries from Manzala Wetland, Egypt

Desouky, Mohammed; Mehanna, Sahar

doi:10.21608/ejabf.2025.442757

Applying CMSY and BSM to Estimate Stock Status and Biological Reference Points of the Nile Tilapia and African Catfish Fisheries from Manzala Wetland, Egypt

Authors

10.21608/ejabf.2025.442757

Abstract

Effective fisheries management relies on accurate stock assessments to ensure sustainable exploitation and long-term ecosystem stability. This study assessed the stock status of two key commercial species in Manzala wetland, Egypt: The Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus). Historical catch data were analyzed using both the Catch-MSY (CMSY) and Bayesian Schaefer Model (BSM) to estimate critical biological parameters, including growth rates, carrying capacities, maximum sustainable yields (MSY), and fishing mortality rates (F_msy). Results showed that O. niloticus had MSY of approximately 22,675–23,500 ton per year, while C. gariepinus had MSY of about 14,213–14,750 ton per year. Biomass levels in 2022 were estimated at 73–75% of carrying capacity for O. niloticus and 63–65% for C. gariepinus, indicating healthy and sustainable stock conditions. Fishing mortality rates for both species were below critical thresholds. The agreement between CMSY and BSM outcomes supports the robustness of the findings. Comparisons with similar regional fisheries confirmed the validity of the estimates. However, environmental variability, multi-species interactions, and changes in fishing effort should be closely monitored to maintain long-term sustainability. This study provides essential baseline information to guide evidence-based fisheries management in Manzala wetland.

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