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

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.

Socio-Economic Conditions of Small-Scale Hilsa Fishers in the Meghna River Estuary of Chandpur, Bangladesh

“…Instead, they get only 30-35 kg of rice per month. The findings are more or less similar to the study of [10,23], which stated that more than half of the fishers did not receive sufficient incentives from the government during the prohibition period due to nepotism and corruption. In addition, the government has also initiated some programs to support alternative income-generating activities such as supplying cash, rickshaw/van, and sewing machines to compensate for the loss of earnings resulting from the fishing ban periods [23].…”

“…Hilsa fish (the national fish/ GI indicator) is the largest single-species fishery in Bangladesh, contributing the highest to around 14% of the country's total fish production and 47% of total marine catch [9]. This fishing has become the "social and economic driving force" of the country [10], characterized by the usual conditions of joint ownership, using the resources available to fishers [11]. The total annual value of the hilsa fishery is USD 1.3 billion, accounting for more than 1% of Bangladesh's total GDP and directly or indirectly supporting the livelihoods of 4 million people of Bangladesh [8].…”

Stock Assessment and Rebuilding of Two Major Shrimp Fisheries (Penaeus monodon and Metapenaeus monoceros) from the Industrial Fishing Zone of Bangladesh

“…Estimating MSY is critical for policymakers when developing a sustainable harvest strategy [69], and DB-SRA can reduce uncertainty in estimating this quantity [46]. However, there was a large discrepancy observed in the estimates of MSY between the present and previous studies of Barua (2020 and2021) [23,43].…”

Length-Based Stock Assessment for the Data-Poor Bombay Duck Fishery from the Northern Bay of Bengal Coast, Bangladesh

“…Despite its enormous social and economic importance, this fishery is suffering from different human-induced activities such as overfishing [8]. As a result, extensive monitoring of this fishery through stock assessment is required to develop long-term effective management strategies to ensure sustainability [9][10][11][12][13][14]. In the literature, there are only four studies on Bombay duck stock assessment [15][16][17][18] from the marine water of Bangladesh.…”