Abstract:
Being one of the primary fishing targets in Chinese pelagic fishing, Pacific saury (
Cololabis saira) is distributed in the subtropical to temperate waters of the northwest Pacific Ocean. In order to explore its resource status, according to the catch-at-size and biological data of Northwest Pacific saury from 2014 to 2018, we conducted a performance test and a sensitivity analysis on length-based cohort analysis (LCA) model and biomass-based length-cohort analysis (B-LCA) model. Besides, we applied Monte Carlo method to estimate the model parameters, resource quantity, fishing mortality coefficients and maximum sustainable yield of Pacific saury. The results show that: 1) The LCA model and B-LCA model exhibited excellent fitting abilities at 5, 10 and 15 mm length intervals, with stronger fitting abilities at 5 mm interval. 2) LCA model performed better for fishery data in units of number, while B-LCA model performed better for fishery data in units of mass. 3) Both LCA and B-LCA models were sensitive to changes in allometric factor ( b )and asymptote length ( L_\infty ), with higher sensitivity to
b. 4) The average resource mass of Pacific saury from 2014 to 2018 estimated by LCA model was about 65.93×10
4−171.51×10
4 t; the fishing mortality coefficient was 0.529 2; the maximum sustainable yield was 37.73×10
4 t. The average resource mass estimated by B-LCA model was about 47.88×10
4−126.25×10
4 t; the fishing mortality coefficient was 0.540 5; the maximum sustainable yield was 33.02\times 10^4 t. The maximum sustained production estimated by both models was lower than the average annual production of NPFC (North Pacific Ocean Commission) member countries ( 40.98\times 10^4 t), indicating that the Pacific saury resources had been overfished from 2014 to 2018.