Search

Fish eggs and larvae were analysed from 63 vertically stratified plankton hauls in the Irish Sea and southern North Sea. The dominant species were sprat (Sprattus sprattus), dragonet (Callionymus spp.), dab (Limanda limanda) and to a lesser extent rockling species, sandeel (Ammodytes spp.), whiting (Merlangius merlangus) and flounder (Platichthys flesus). There was little difference between species in the vertical distribution of either eggs or larvae. Most were concentrated in the upper 50 m of the water column, eggs in progressively increasing numbers towards the surface and larvae with a sub-surface peak at a depth of 10–15 m. The vertical distribution of eggs extended deeper in the water column than larvae, possibly due to some combination of eggs being spawned deeper and their passive susceptibility to turbulent mixing. There were no significant differences between day and night distributions and under mixed or isothermal conditions. [ABSTRACT FROM PUBLISHER]

Larvae of sprat (Sprattus sprattus) from mixed and stratified water column sites in the German Bight of the North Sea were assessed for nutritional condition by analysis of total carbon and nitrogen and the lipid fractions triacylglycerol (TAG), cholesterol, and polar lipids. There was no indication of any significant variation in condition index related to diel sampling periodicity, based either on percentage carbon composition or TAG/cholesterol ratio. Inclusion of growth data from otolith ring counts with the carbon and lipid results identified larvae at 9-10 mm in length as being in relatively poor condition. There was some evidence from carbon analysis to suggest that larvae in poor condition were more prevalent at the stratified site than the mixed; however, microzooplankton analysis showed mean food abundance for larvae was slightly higher at the mixed site. The results from the condition analyses and the validity of the methods is discussed in relation to studies of survival of fish larvae. [ABSTRACT FROM PUBLISHER]