Abstract
Factors affecting spawning and larval survival in marine fish are of fundamental importance in understanding population demography. Physiological processes associated with reproduction and early larval growths are regulated, in part, by water temperature, which also affects the phytoplankton bloom and thereby the zooplankton peak. In the northern hemisphere temperatures are predicted to increase by 3-6º C by the year 2100 due to global warming. These temperature changes may have dramatic effects on the reproductive success of marine fish, but to predict effects at the population level it is necessary to understand how climate change will affect physiology and maturation at the individual level. We specifically chose to examine this question for the Northeast Artic cod (Gadus morhua) evaluating the effect of increasing sea temperatures on recruitment success through the complex interplay with spawning time, fish size, overlap with zooplankton abundance and larval survival in a theoretical conceptual model.
This presentation will be divided into three parts: 1) a short personal introduction, 2) general principles within fish reproductive biology using Atlantic herring and cod as contrasting examples and 3) the Lofoten case, referring to a co-operative work with Jon Egil Skjæraasen (IMR), Fransisco Rey (IMR) and Christian Jørgensen (UoB).
Olav Sigurd Kjesbu, Institute of Marine Research