Vulnerability Assessment of Target Shrimps and Bycatch Species from Industrial Shrimp Trawl Fishery in the Bay of Bengal, Bangladesh

Umme Kaniz Fatema,Hiroyuki Matsuda,Hasan Faruque,Md Abdus Salam

doi:10.3390/su14031691

Abstract

Productivity susceptibility analysis (PSA) is a semi-quantitative ecological risk assessment tool, widely used to determine the relative vulnerability of target and non-target species to fishing impacts. Considering the available information on species-specific life-history and fishery-specific attributes, we used PSA to assess the relative risk of the 60 species interacting with the shrimp trawl fishery in the Bay of Bengal, Bangladesh. Penaeus monodon, the most important target, and Metapenaeus monoceros, the highest catch contributor, along with other 15 species were in the moderate-risk category, while seven non-target bycatch species were in the high-risk category. PSA-derived vulnerability results were validated with IUCN extinction risk, exploitation rate and stocks’ catch trend. The majority of the identified species showed high productivity (37%) and high susceptibility (46%), and all the moderately and highly vulnerable species were subjected to overfishing conditions by shrimp trawl fishery, which coincided with the vulnerability scores (V ≥ 1.8). Species with V ≥ 1.8 mostly showed a decreasing catch trend, while the species with a stable or increasing catch trend had a V ≤ 1.72. Data quality analysis of productivity and susceptibility attributes indicated that the majority of species were considered data-limited, which emphasizes the acquisition of data on spatio-temporal abundance, catch and effort, and biological information specifically relating to species age, growth, and reproduction. However, our findings can assist fishery administrators in implementing an ecosystem approach to ensure the sustainability and conservation of marine biodiversity in the Bay of Bengal.

Highlights

The Bay of Bengal, the northeastern part of the Indian Ocean, is enriched with coastal and marine ecosystems and is considered a potential ground for marine species diversity, including shrimps [1,2]
When scoring the categories for the attribute of “breeding cycle”, we considered a score of 3 for species that have an annual cycle with a protracted breeding season, i.e., they breed throughout the year or have an extended breeding season, a score of 2 for species that have an annual cycle with a seasonal peak, and a score of 1 for species that have bi/triennial breeding cycles [38]
The overall productivity and susceptibility scores showed that 37% and 46% of all the identified species had high productivity and high susceptibility scores, respectively, while 36% and 27%, respectively, had moderate and low productivity scores, and 44% and 11%, respectively, had moderate and lower susceptibility (Figure 3a)

Summary

Introduction

The Bay of Bengal, the northeastern part of the Indian Ocean, is enriched with coastal and marine ecosystems and is considered a potential ground for marine species diversity, including shrimps [1,2]. Industrial trawlers (i.e., shrimp and fish trawlers), the most significant component of commercial fisheries in the Bay of Bengal, have been engaged in carrying out fishing on a large scale in the Exclusive Economic Zone (EEZ) of Bangladesh [3]. The catch per unit fishing effort has been declining, and some species of marine shrimp and fish stocks are being depleted [5,6,7]. The natural harmony of aquatic ecosystems has been disrupted by the over-exploitation of marine resources [8,9].

Methods

Results

Discussion

Conclusion