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Size-dependent winter mortality of age-0 pikeperch ( Stizostedion lucioperca ) in Pärnu Bay, the Baltic Sea

2000; Canadian Science Publishing; Volume: 57; Issue: 2 Linguagem: Inglês

10.1139/f99-270

1205-7533

Jyrki Lappalainen, Vaike Erm, Jakob Kjellman, Hannu Lehtonen,

Marine Bivalve and Aquaculture Studies

Winter mortality of pikeperch (Stizostedion lucioperca) at age 0 is dependent on size, based on samples collected with trawls during 1961-1994 in Pärnu Bay, Estonia. Mortality increased as mean length of pikeperch in the first autumn decreased. The size-dependent mortality was analysed as correlation between mean lengths at age 0 in autumn and changes in mean lengths between age 1 and age 0. When the varying lengths at age 0 were taken into account, the duration of winter also affected mortality; longer durations of ice cover resulted in less size-dependent winter mortality. Since mean length at age 0 in autumn correlated positively with summer water temperature, winter mortality can be expected to decrease the warmer the summer.