Feeding of Baltic herring and sprat in the period 1986-1996 in relation to their state and biomas

Feeding of Baltic herring and sprat in the period 1986-1996 in relation to their state and biomas
Bulletin of the Sea Fisheries Institute 3 (142) 1997, pp. 73-83

Jerzy SZYPUŁA¹, WŁODZIMIERZ Grygiel² and Miros�aw Wyszy�ski²
¹Academy of Agriculture, K. Królewicza 4, 71-550 Szczecin, Poland
²Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland

Key words: herring, sprat, southern Baltic, condition coefficient, stock biomass, feeding.

Abstract.
The obtained results point to a similar character of correlations between the changes in the state of the southern Baltic herring (r = -0.7509) and sprat (r = -0.7233) in the period 1986-1996 and the changes in the biomass of their populations. At the same time, in herring, a very clear correspondence has been observed between the changes in their state and the changes in the share of macroplankton and benthos in the diet.