ICES Journal of Marine Science: Journal du Conseil Advance Access originally published online on June 2, 2007
ICES Journal of Marine Science: Journal du Conseil 2007 64(5):956-962; doi:10.1093/icesjms/fsm068
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Vertical distribution of Baltic sprat larvae: changes in patterns of diel migration?
Leibniz-Institute of Marine Sciences, Düsternbrooker Weg 20, 24105 Kiel, Germany
Correspondence to R. Voss: tel: +49 431 600 4557; fax: +49 431 600 4553; e-mail: rvoss{at}ifm-geomar.de
Voss, R., Schmidt, J. O., and Schnack, D. 2007. Vertical distribution of Baltic sprat larvae: changes in patterns of diel migration? ICES Journal of Marine Science, 64: 956962.Ontogenetic and diurnal vertical migration patterns of Baltic sprat larvae were investigated for the periods 19891990 and 19982002. Comparison of the results led to the hypothesis that the diel vertical migration behaviour of sprat larvae >10 mm has changed. In 1989 and 1990, sprat larvae migrated to the surface at night, whereas they stayed 3050 m deep by day. From 1998 to 2002, sprat larvae showed no signs of diel vertical migration, remaining in warmer, near-surface water by day and night. This behavioural change coincided with a more general change in the Baltic ecosystem, i.e. an increase in near-surface temperature and a general increase in abundance of the major prey organism (Acartia spp.) of Baltic sprat larvae, with more pronounced aggregation in surface waters.
Keywords: Baltic Sea, behavioural change, diel migration, prey availability, sprat larvae, vertical distribution
Received 14 September 2006; accepted 9 April 2007; advance access publication 2 June 2007.