Application of a Delay-difference model for the stock assessment of southern Atlantic albacore (Thunnus alalunga)

作者：Zhang Kui; Liu Qun^*; Kalhoro Muhsan Ali

来源：Journal of Ocean University of China, 2015, 14(3): 557-563.

DOI：10.1007/s11802-015-2517-0

• delay-difference model
• albacore (Thunnus alalunga)
• catch per unit effort
• Ricker model
• stock-recruitment relationship
• maximum sustainable yield

Delay-difference models are intermediate between simple surplus-production models and complicated age-structured models. Such intermediate models are more efficient and require less data than age-structured models. In this study, a delay-difference model was applied to fit catch and catch per unit effort (CPUE) data (1975-2011) of the southern Atlantic albacore (Thunnus alalunga) stock. The proposed delay-difference model captures annual fluctuations in predicted CPUE data better than Fox model. In a Monte Carlo simulation, white noises (CVs) were superimposed on the observed CPUE data at four levels. Relative estimate error was then calculated to compare the estimated results with the true values of parameters alpha and beta in Ricker stock-recruitment model and the catchability coefficient q. a is more sensitive to CV than beta and q. We also calculated an 80% percentile confidence interval of the maximum sustainable yield (MSY, 21756 t to 23408 t; median 22490 t) with the delay-difference model. The yield of the southern Atlantic albacore stock in 2011 was 24122 t, and the estimated ratios of catch against MSY for the past seven years were approximately 1.0. We suggest that care should be taken to protect the albacore fishery in the southern Atlantic Ocean. The proposed delay-difference model provides a good fit to the data of southern Atlantic albacore stock and may be a useful choice for the assessment of regional albacore stock.

• 出版日期2015-6
• 单位中国海洋大学