渤海秋汛对虾数量预报方法的研究

A STUDY ON THE METHOD OF PREDICTION FOR THE AUTUMNAL PRAWN CATCHES IN PO HAI

渤海秋汛对虾的数量预报,是我国渔业预报中比较成功的报例之一。本文简述了此项预报工作的发展过程,介绍取得预报指标——相对资源量的原则和方法、加权系数的推算以及对各种回归方程的预报效果的检验结果,提出了针对不同资源水平的预报计算方法。此外,还对有争议的预报中的渔捞努力量因素问题进行了讨论。

It was possible to estimate the productivity based on the relative abundance indexobtained by catches of juvenile prawns (Penaeus orintalis). Since the resource andthe area of distribution of juvenile prawns in three bays of Po Hai are unequal, itis nacessary to use the weight coefficients by approximate method in the estimation.It is found that the optimal weight coeffcients for Liaodong Wan, Pohai Wan andLaizhou Wan of Po Hai are 1. 75, 4. 25 and 4. 00 respectively. The result of statistical analysis shows that there is a simple linear relationship between the catches and the relative abundance index. At present, within the range ofthe recent fishing effort, the varied effort has little significance in the prawn fishery. In recent years. owing to the increase of the resource of prawns (When the rela-tive abundance index is more than 1,000) it is found that there existed a signifcantdifference in number of the predicted values, as compared with the actual yields. Hen-ce, we have amended the prediction method as follows: 1. The catches are predicted by the relative abundance indexes. Thus, we haveY = 37.57e^(-1.054-3x), where Y the predicted catches, x the relative abundance index. 2. If the relative abundance index was more than 1,000, we may have to predictwith equation (4) and if it was less than 1,000, we may have to predict with equation(3).