Состояние запасов и степень эксплуатации сельди восточного побережья Балтийского моря.

Abstract

This paper deals with data on the herring fishery in subareas 28, 29, 32 and, to a lesser extent, in subarea 28 of the Baltic classified according to season, years and periods covering several years. It is shown that the volume of herring catches has increased due to intensification of the fisheries and extention of the fishing grounds. At the same time, a decrease in the catches per unit effort has been observed as a result of the decline in the herring stocks. The decline in the stocks in recent years is due to the fact that, in comparison to previous years, younger year classes have predominated and that the influence of trawl fishery on cod, the stocks of which increased in 1966, has increased. The herring stocks increased in the Wisla Bay in recent years due to the addition of mature year classes. The structure of the herring stocks is investigated according to populations and areas. It has been proved that the level of exploitation of the herring stocks has recently reached its optimum in the subareas 28, 29 and 23 and that a further increase in fishing intensity will lead to economically and biologically irrational exploitation. Measures which have been introduced in the Soviet Union for the protection and enlargement of herring stocks are stated.