Stock assessment of wels catfish (Silurus glanis Linnaeus, 1758) in the Aras Dam reservoir, northwest Iran

Authors

1 Department of Ecology and Aquatic Stocks Management, Artemia and Aquaculture Research Institute, Urmia University, P.O. Box: 57179-44514, Urmia, Iran

2 Department of Natural Resources and Environmental Engineering, School of Agriculture, Shiraz University, Shiraz, Fars, Iran

10.22092/ijfs.2025.134858

Abstract

The wels catfish (Silurus glanis) is a widely distributed freshwater species of considerable ecological and commercial importance. Among its principal habitats is the Aras reservoir in northwestern Iran, where it constitutes one of the dominant targets of the regional fishery. However, unregulated fishing has led to a reduction in the stock abundance. The present study investigated the length–weight relationship and assessed the stock status of wels catfish in the Aras Dam reservoir. Stock assessment was conducted using the CMSY++ model. Model outputs indicated that both the relative stock size (B/BMSY) and relative fishing mortality (F/FMSY) were below unity, suggesting that the stock is currently subject to excessive fishing pressure. The maximum sustainable yield (MSY) was estimated at 2.98 metric tons. Historical data revealed that actual catches consistently exceeded the MSY until 2015. Thereafter, owing to intensive exploitation and a subsequent decline in stock biomass, annual catches fell below the MSY. The Kobe plot analysis demonstrated that overfishing has driven the population into the overfished quadrant. Collectively, these findings underscore the urgent necessity of implementing ecosystem-based fisheries management strategies. In particular, stricter regulation of fishing practices, enforcement of annual catch limits, reduction of fishing effort, and control of illegal harvest are strongly recommended to halt further depletion and to ensure the long-term sustainability of Wels catfish in the Aras Dam reservoir.

Keywords

Iranian Journal of Fisheries Sciences
Volume 25, Issue 1
January 2026
Pages 127-140

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