Fish Stock Assessment for Data-Poor Fisheries, with a Case Study of Tropical Hilsa Shad (Tenualosa ilisha) in the Water of Bangladesh

Md. Abdullah Al-Mamun,Mohammed Shahidul Alam,Qun Liu,Md. Rashed-Un- Nabi

doi:10.3390/su13073604

Md. Abdullah Al-Mamun, Mohammed Shahidul Alam + Show 2 more

Open Access

https://doi.org/10.3390/su13073604

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Abstract

The anadromous tropical Hilsa shad formed the largest single-species fishery in Bangladesh, making the highest contribution to the country’s total fish production (14%) and nearly 83% of the global Hilsa catch in 2018. However, increased fishing pressure made the fishery vulnerable, and hence, information on the stock condition and its response to the current degree of removal is essential to explore the future potential for sustainable exploitation. This study carried out a rigorous assessment based on three different methodological approaches (traditional length-frequency based stock assessment method for fishing mortality and exploitation, Froese’s length-based indicators for fishing sustainability, and a surplus production-based Monte Carlo method-CMSY, for fisheries reference points estimation) for the best possible estimates of the Hilsa stock status in the water of Bangladesh. The present findings revealed that the stock is likely to be overfished due to over-exploitation. Depending on the outputs, this study recommended a lower length limit for the catch (>33 cm), distinguished a selectivity pattern (mesh size limit ≥ 8 cm), and proposed a yearly landing limit (within the range of 263,000–315,000 tons) for the sustainable management of the Hilsa fishery in Bangladesh.

Highlights

Accepted: 18 March 2021The sustainability of marine fisheries became a global concern because of the rapid increase in fishing pressure and arbitrarily exploitation, which may cause negative consequences for the ecosystems and societies [1]
This situation is worse, in developing countries where proper management tools and political will lack and pervasive illegal fishing of juvenile and brood fishes is the fisheries’ governing features [2,3,4]. This worst-case scenario of the stocks provides the impetus for articulating effective management tools, focusing on all concerned stakeholders’ participation to promote conservation of the ecosystems and achieve the optimum yields to sustain the livelihoods and sustainable food supply [4,5]
The Hilsa shad, Tenualosa ilisha (Hamilton, 1822), is a member of the Clupeidae family shows a wide range of distribution from the northern part of the Bay of Bengal to the Arabian Sea regions and some parts of coastal Southeast Asia [8,9,10,11,12]

Summary

Introduction

The sustainability of marine fisheries became a global concern because of the rapid increase in fishing pressure and arbitrarily exploitation, which may cause negative consequences for the ecosystems and societies [1] This situation is worse, in developing countries where proper management tools and political will lack and pervasive illegal fishing of juvenile and brood fishes is the fisheries’ governing features [2,3,4]. This worst-case scenario of the stocks provides the impetus for articulating effective management tools, focusing on all concerned stakeholders’ participation to promote conservation of the ecosystems and achieve the optimum yields to sustain the livelihoods and sustainable food supply [4,5]. Hilsa spends most of their adult lives at sea and migrates towards the freshwaters, virtually in every accessible

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