Состав, состояние и эксплуатация запаса балтийской трески и ее значение в пищевых цепях.

Abstract

On the basis of investigations on the dynamics of the productivity of year classes within the yields and of growth, mortality, distribution of cod in the eastern Baltic and the dynamics of total cod catches and catches per unit effort, the structure and state of the cod stocks have been estimated and natural and the fishing mortality (M = 0,3-0,4; F = 0,5-0,7) and growth constants Lg = 99-120 cm, K = 0,11-0,146) have been determined. The estimation of the level of exploitation shows that fishing intensity lies within or near the limits of the optimum range. It is shown that regulation of the minimum, length and regulation of the percentage of young fish as by-catch can be of considerable practical use. The absolute cod resources in the eastern Baltic as well as the amount of food taken in are determined and it is shown that cod form a significant factor in the natural mortality of herring and sprat.