Fishing and biological characteristics of the Baltic herring in Ventspils zone of the Baltic Sea

Abstract

Data on the size-age composition of the Baltic herring (Clupea harengus membras) stock in the Ventspils area (Baltic Sea), the annual cycle of the maturity stages of their gonads, the stomach fullness, and the fat accumulation in the gut are given. It is shown that the most active fishing is carried out in May-June. The changes in the composition of the Baltic herring population in the annual cycle depend on the spawning migration of the sea herring to the Gulf of Riga and the feeding migrations of herring. Baltic herring feeds all the year round, the maximum feeding intensity occurs in June-August. The fat accumulation in herring guts begins in May, reaches its maximum in July and the amount of fat gradually decreases beginning from September.