Päivi Laine

Female Baltic herring Clupea harengus allocate resources from growth to reproduction in poor feeding conditions

The trade-off between somatic growth and reproduction in the female Baltic herring Clupea harengus was investigated from 1984 to 2002. During the study period, growth decreased, as a consequence of decreasing salinity and weakening of feeding conditions. Production of muscle and ovarian tissue decreased in repeat spawners, but investment in reproduction took an increasing amount of the total production of new tissues. This suggested that a shift in allocation to reproduction takes precedence over body growth in the reproductive strategy of C. harengus. The process also indicated one possible mechanism leading to dwarf forms in fish populations.

Reproduction of Baltic herring after dissimilar growth and overwintering seasons

Abstract In the Baltic Sea, there are large annual differences in sea water temperature and in the duration of ice cover. We studied the variation in the somatic growth (measured as relative otolith increment) and reproductive parameters of female Baltic herring in the years 1988-94. During this period, the number of ice days varied from 0 to 122, the temperature sum (calculated from monthly means) of winter months (December-March) from 0.65 to 3.8°C and the temperature sum of summer and autumn months (July-November) from 60.0 to 69.5¼C. There were annual differences in the fecundity and gonadosomatic index of females but not in egg weight. Also, the somatic growth of females varied annually, and it changed in relation to the temperature of the growth season. Neither the length of the ice cover period nor the overwintering temperature was significantly connected with the reproductive parameters studied, but the mean temperature of the March preceding the spawning was inversely related to fecundity. The Ba...

Corrigendum to “Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas – Implications for environmental monitoring” [Ecol. Indic. 50 (2015) 196–205]

Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas - Implications for environmental monitoring (vol 50, pg 196, 2015)