한국 해역의 살오징어(Todarodes pacificus) 복수어업 현황 및 베이지안 상태공간 생산량 모델의 적용

Abstract

The common squid (Todarodes pacificus) is an important commercial species accounting for approximately 15% of the total fishery yield in Korean waters from 2000 to 2018. In addition, it is one of the representative species caught by various fishing gears. However, in South Korea, multiple fisheries of the common squid are not systematically organized, and stock assessment of the common squid has not yet been conducted. Nonetheless, given that the catch per unit effort (CPUE) and yield data collected over a long period of time for each fishery are recorded, the use of the surplus production model may represent an alternative strategy to overcome these issues. This study aimed to clarify the schematic diagram of the common squid fishery classification and to apply common squid data (CPUE and yield data) to a Bayesian state-space production model. Analysis of the multiple fishery using the Bayesian state-space production model with multiple CPUE data was performed, rather than with single CPUE data being treated independently. Numerical optimization was performed using the TMB package in R, and the point estimates of the parameters and uncertainties were calculated. The estimated annual biomass was in the range of 283,007 to 995,483 MT, the estimated intrinsic growth rate was 1.06, and the estimated carrying capacity was 970,501 MT. Moreover, maximum sustainable yield and its corresponding biomass (BMSY) were estimated to be 258,793 MT and 484,250 MT, respectively. Comparison with available results from stock assessment of independently analyzed single fisheries revealed a large difference from the estimated values, suggesting that the results based on single fisheries may not be reliable. Hence, stock assessment based on multiple fisheries should be performed in order to achieve a more comprehensive and reliable stock assessment.