【摘要】 我们用各种方法估算了秋汛渤海对虾(Penaeus orientalis Kishinouye)的死亡值。总死亡系数的估算结果:用渔获尾数为相对资源量估计的10年平均旬死亡值,雌虾约0.25,雄虾约0.34;用y/f为相对资源量估计的12年旬平均死亡值,雌虾0.23,雄虾0.34;用世代分析(Pope 方法)估计的3年雌虾旬平均死亡值约0.30。交尾后部份雄虾死亡,我们找到了一个用性比资料估算雄虾交尾死亡的方法。估算结果,到10月末,雄虾交尾死亡系数约为0.65,并有陆续死亡现象,到12月初的累计死亡系数约1.05左右。我们在讨论了渤海秋汛对虾渔业的 F和f之间的关系后,认为当 f<1000,捕捞死亡随捕捞努力量的变化而变化;当f>1000,捕捞努力量的变化对捕捞死亡已无多大影响,所以渤海秋汛对虾渔业平均每 10天的捕捞死亡系数不能大于0.3。更多还原

【Abstract】 The mortality of the Pohai Sea prawns in autumn has been estimated with avariety of methods. After mating, male prawns die in large numbers. We have found that undersome assumptive conditions the mating mortality of male prawns may be estimated withsex ratio. The results are Iisted in table 2. The mating mortality is about 0.65 in lateOctober. The accumulative value of mating mortality of male prawns is about 1.05 inesrly December. The total mortality of Pohai Sea prawns have been estimated. The results are asfollows. The catch in number per month and catchpereffort as indices of abundanceare regressed against time to calculate the total mortlity. For ten-day average in 10years is about 0.25 for femals 0.34 for mals, and that in 12 ysars about 0.23 forfemals 0.34 for mals. Now we assume that the natural mortality of female prawns maybe negligible in comparison with its fishing mortality, then the total mortality of femaleprawns is approximately equal to its fishing mortality which is about 0.25 per ten-dayperiod in about 800 standard unit of fishing effort. Therefore the catchability is equalto 3.125×10^-4. After discussing the relationship between mortality and fishing effort, we confirmthat when fishing effort is less than 1000, fishing mortality varies with effort, andwhen fishing effort is greater than 1000, the increase in effort has little influence onfishing mortality. The fact shows that there is a certain limit, being about 0.3perten-day period to fishing mortality with regard to the prawn fishery in the autumnfishing season.更多还原