应用Beverton-Holt单位补充量产量模型估算东海区带鱼生物学参考点F0.1和FMSY

Estimation of biological reference points F_(0.1) and F_(MSY) for Trichiurus japonicus in the East China Sea by using the Beverton-Holt yield-per-recruitment model

应用Beverton-Holt单位补充量产量模型,估算东海区带鱼生物学参考点F0.1、FMSY及其对应的MSY、Y0.1,并探讨了开捕年龄tc与上述生物学参考点的关系。结果表明,在当前的开捕年龄条件下,带鱼的F0.1比FMSY降低了31.71%,而单位补充量产量Yw/R只下降了4.46%;F0.1、FMSY随tc的提高而不断增大;若以MSY/R为管理目标,当tc为3.08龄时,Yw/R取得最大值329.41 g,可承受较大的捕捞强度;若以Y0.1/R为管理目标,当tc为2.50龄时,Yw/R取得最大值281.32 g,而F0.1仅为0.66。

Fo.1 and FMSY are two of the most commonly used biological reterence points in fisheries management. FMSY is defined as the fishing mortality rate in that case maximum sustainable yield （MSY） is attained, and F0.1 is the fishing mortality rate in this case the marginal increase in yield is 10% of that at F of 0. In this study, using Trichiurus japonicus in the East China Sea as an example, the Beverton-Holt yield-perrecruitment model was applied to estimate F0. 1, FMSY and corresponding yield per recruitment. The relationship between those biological reference points and the age at first capture （tc） was also discussed. At the current mortality and age at first capture, F0.1 decreased 31.71% as compared with FMSY, and yield per recruitment （YW/R） only reduced 4.46%. F0.1 tends to be substantially lower than FMsy but yield per recruitment at F0.1 tends to be only slightly lower than at FMSY The result also showed that the trend of F0.1 and FMSY increased with the increasing to, but F was not always available because F value was big enough for fisheries management when tc was near a certain critical level. According to the yield per recruitment analysis, if MSY/R was considered a management target, maximum yield per recruitment was 329.41 g when tc increased to age 3.08, and FMSY could keep high level. At the target point of Y0. 1/R, the yield per recruitment was highest with 281.32 g while tc of 2.50 year as well as F0.1 of 0.66. According to the current values of to and F, the current yield per recruitment was only about 79.03 g. Not only do the current F of 2.51 exceeded the reference points F0.1 and FMSY, but also the current age at first capture of 0.29 year was much lower than the tc for the optimum yield, it revealed Trichiurus japonicus in the East China Sea has been over exploited.