A comparative study on the abundance of fish fry in the North Sea in late winter and their predation by fish

Nawa, Ikwen Gregory (1979) A comparative study on the abundance of fish fry in the North Sea in late winter and their predation by fish (Diploma thesis), Christian-Albrechts-Universität, Kiel, Kiel, Germany, 69 pp

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Abstract

The first part of this study gives a comparative account of regional distribution and abundance of fish fry in the North Sea in late winter. The second part deals with the predation of fish fry by three species of fish: herring, sprat and mackerel. Material for these studies was collected in Jan/Feb. 1975. Plankton tows were made with a modified Gulf-V-Sampler "Nackthai"; stomach samples of the three species of fish mentioned above and collected in the immediate vicinity of some plankton stations were examined. Results obtained show that areas of highest concentration of fish eggs lie in the English Channel, Southern Bight, German Bight and the Viking Bank. Plaice eggs make up about 18% of the total number of eggs, and areas of greatest abundance lie in the first three regions mentioned above. Early stages of development dominated in all sub-areas. The highest concentrations of fish larvae were found in the German Bight and Viking Bank. The most abundant taxa collected were Ammodytes spec. (90%),P.virens (4.8%),P.platessa (2.3%) and C.harengus (1.3%).Most of the larvae have a length below 10mm. Plaice eggs were found in the stomach of herring and sprat and smaller eggs in the mackerel.Herring was not feeding on larvae but Ammodytes spec. was an important diet of sprat. Mackerel seem to prefer clupoid larvae.Differences in food composition were observed between the three fish species and their length groups.Other items like copepods,euphausids, mysids,fish scales and parasites were also found in the stomachs examined.

Document Type: Thesis (Diploma thesis)
Thesis Advisors: Nellen, Walter
Research affiliation: OceanRep > Institute for Marine Science Kiel
Date Deposited: 22 Jan 2020 11:39
Last Modified: 22 Jan 2020 11:39
URI: http://eprints.uni-kiel.de/id/eprint/48808

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