Assessing Five Major Exploited Tuna Species in India (Eastern and Western Indian Ocean) Using the Monte Carlo Method (CMSY) and the Bayesian Schaefer Model (BSM)

Ubair Nisar,Yongtong Mu,Rafiya Ali,Yu Sun

doi:10.3390/su13168868

Ubair Nisar, Yongtong Mu + Show 2 more

Open Access

https://doi.org/10.3390/su13168868

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Abstract

The status of data-limited tuna fishery stocks in India has been tested using the latest and most advanced computerized methods, CMSY and BSM. Five tuna fish stocks from both the Eastern and Western Indian Ocean were assessed using both catch and catch per unit effort (CPUE) details available from 1990 to 2015. Both methods help to calculate the maximum sustainable yield (MSY) and exploitation of MSY relative to biomass (B/BMSY). The results of maximum intrinsic rate (r) and carrying capacity are also estimated. The results revealed that all tuna stocks in both the regions were overfished, with one, the longtail tuna (Thunnus tonggol) in the Western Indian Ocean strongly overfished (B/BMSY = 0.44). Such observations, although still preliminary since the techniques used to produce them are relatively new, often associated with the situation and exploitation of all the stock in question, making the CMSY and BSM methods promising for stock assessment in data-deficit situations. The study concludes that in order to restore the status of these five tuna stocks in both regions, it would be necessary to reduce the fishing pressure.

Highlights

The data of fisheries obtained from the Food and Agriculture Organization (FAO)revealed that global fish landings have been declining steadily since 1996 [1], with catches declining by 1.2 million tons annually since due to illegal, unreported fishing and undocumented (IUU) fishing [2,3]
The B/BMSY values for all 10 tuna fishery stocks assessed in India from the Eastern
Active r–K pairs analyzed by CMSY and Bayesian Schaefer Model (BSM) methods produce triangular-shaped clouds in the plot’s space, where the r–K pair most likely is located at the top of the triangle (Figure 2)

Summary

Introduction

The data of fisheries obtained from the Food and Agriculture Organization (FAO). Revealed that global fish landings have been declining steadily since 1996 [1], with catches declining by 1.2 million tons annually since due to illegal, unreported fishing and undocumented (IUU) fishing [2,3]. The proportion of fish stocks within biologically sustainable levels, which was 90% in 1990 and 65.8% in 2017, can be used to understand the overfishing status of global fisheries [4]. For Asian fisheries, the situation is even worse [5]. Due to high fishing pressure on the stock [6]. In order to reduce the fishing pressure of a particular fish stock, total allowable catch (TAC). Different species of tuna are distributed widely all around the globe but are found from temperate to tropical waters around the equator between 45 degrees North and

Methods

Results

Discussion

Conclusion