Using Bayesian Bio-economic model to evaluate the management strategies of Ommastrephes bartramii in the Northwest Pacific Ocean

Abstract

The neon flying squid (Ommastrephes bartramii) in the Northwest Pacific Ocean is one economically important cephalopod, largely exploited by squid jigging fleets from Chinese Mainland, Japan, and Chinese Taibei. In this study, a Bayesian Bio-economic model was developed using fishery data from Chinese Mainland, Japan, and Chinese Taibei, and relevant fishery economic data from Chinese Mainland. The stock assessment and risk analysis of alternative management strategies for O. bartramii were carried out. Three prior distributions (i.e., uniform, normal and logarithmic normal) for model parameters were assumed in different scenarios. The results showed that the estimated model parameters and reference points such as maximum sustainable yield (MSY), maximum economic yield (MEY), bio-economic balance point (BE) and fishing mortality were similar in the scenarios of normal and logarithmic normal prior assumptions. However, the estimates were larger in the scenario of uniform prior assumption. The fishing mortalities and annual catches from 1996 to 2008 were lower than the reference points F0.1 and MSY in all the three scenarios, indicating that O. bartramii stock is at sustainable exploited level. The results of decision analysis indicated that under the same harvest rate, the catch and biomass in 2023 from the uniform assumption were the highest. However, the highest probability of the collapse was found for squid resources after 2023. Our findings suggested that the harvest rate of 0.4 appeared to be the best management regulation under the uniform assumption, and the MSY would be 200 thousand tons. In addition, the harvest rate of 0.5 would be the best management regulation under the other two assumptions, and the MSY would be 180 thousand tons, which balanced the desire for high yields and the healthy population. The results of this study could be used to provide management suggestions for neon flying squid in the Northwest Pacific Ocean.