Applying the Catch-MSY model to the stock assessment of the northwestern Pacific saury Cololabis Saira

The Pacific saury (Cololabis saira) is one of the major harvested species in the temperate waters of the northwestern Pacific Ocean (NPO). The Catch-MSY model uses catch data and basic life history information to estimate the Maximum Sustainable Yield (MSY) for data-limited fisheries. Since there is considerable uncertainty in the current status of the Pacific saury stock in the NPO, the Catch-MSY model was used in this study to estimate MSY on the basis of catch data and life history information from the North Pacific Fisheries Commission (NPFC). During the process, 17 scenarios, according to different prior distributions of the intrinsic rate of increase (r) and carrying capacity (K), were set for sensitivity analysis. Moreover, the influence of different catch time series and different process errors were taken into account. The results show the following: (1) there was a strong negative correlation relationship between ln(r) and ln(K); the MSY increases with an increase in the lower limit of r; (2) The time series of catch data had a limited impact on the assessment results, whereas the results of the model were sensitive to the annual catch in the first and last years; (3) The estimated MSYs of the Pacific saury were 47.37×104 t (41.57×104 t to 53.17×104 t) in scenario S1A and 47.53×104 t (41.79×104 t to 53.27×104 t) in scenario S1B. Given the uncertainty of the Catch-MSY model, maintaining a management target between 50×104 t and 70×104 t was a better management regulation. This study shows that the Catch-MSY model is a useful choice for estimating the MSY of data-limited species such as the Pacific saury.