Náttúrufræðingurinn - 1974, Page 26

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N ÁT T Ú RU F RÆÐINGURINN
Sœmundsson, B., 1926: Fiskarnir. Bókaverslun Sigfúsar Eymundssonar, Reykja-
vík.
Wiborg, K. F., 1948: Some Observation on the Food of Cod of tlie 0—11
Group from Deep Water and the Litoral Zone in Northern Norway and
from Deep Water at Spitzbergen. Fiskeridir. Skr. Havundersk. IX, 4.
— 1949: The Food of Cod of the O—II Group from Deep Waters in some
Fjords of Northern Norway. Fiskeridir. Skr. Havundersk. IX, 8.
— 1960: Investigations on Pelagic Fry of Cod and Haddock in Coastal ancl
Offshore Areas of Northern Norway in July—August 1957. Fiskeridir. Skr.
Havundersk. XII, 8.
S U M M A R Y
Investigations on the Food of Young Fish (O-group) in lcelandic Waters
by
Ólafur K. Pálsson
Marine liesearch Institute, Reykjavik, Iceland
Tlie material of young fisli (O-group) was caught by pelagic trawl in Ice-
landic waters in August 1971. It consists of tlie lollowing species (number of
specimen in brackets): Cod — Gadus morhua (363), liaddock — Melanogrammus
aeglefinus (159), blue whiting — Micromesistius poutassou (85), redfish —
Sebastes marinus (565), capelin — Mallotus villosus (449), total 1621. The
content of the stomachs was identified and counted by the help of a dissecting
microscope.
The length distribution of tlie fishes shows a decrease in length from south
to north. Hadclock and blue whiting are considerably larger than the other
species. The estimated age of the fishes is about 3—6 months.
The iood of the species differs between tlie tliree areas southern, western
and northern Iceland. In each area there are 1—2 groups of food animals,
which were perferred as food by the various fisli species (haddock: 3—4 groups).
Other food animals are not important.
In each area most species have one kind of food in common as an important
reservoir (Calanus finmarchicus in the soutliern and western areas, Acartia in
the nortliern area), besides that every species has specialized on another import-
ant food item as an ecological niche.
Between the various stations the food of the species tliffers considerably,
both qualitatively and quantitatively. Haddock and blue whiting seem to be
more concentrated on stations witli rich supply of food. Cod is concentrated on
stations, on which his preferred food species, Acartia, is numerous. Lack of
food and competition for food sometimes occur among redfish and capelin.
The gadoids do not seem to be involved in any competition for food. This