Fróðskaparrit - 01.01.1971, Page 95

Kaimingar av gongdini hjá fjarðarsild 1 Føroyum
103
roynd á VágsfirSi. Ulrich (1951) sá eisini, at torvur spjaddust,
tá ið sildin tók fø5i til sín, men legði til merikis, at sildin
beinan vegin tók seg saman aftur í torvu, ium hon varð stygd.
Tað er tí hugsandi, at tær væl avmarkaðu torvurnar, sum
sóust á ekkoloddinum, eru torvur, sum eru stygdar saman av
óljóðinum frá motorinum í bátinum.
SUMMARY
In october 1968 investigations on plankton and 1, 2 and 3 years old
herring were carried out durimg 24 hours in Funningsfjørður, Faroe Islands.
Plankton as -well as herring showed vertical migra-tion.
In daytime the main part of the herring and the plankton stayed
from the bottom up to a level of 10 m below the surface, ,in the night
they moved up from bottom coming to the surface entirely.
The echograms showing the movements of the herring form a picture
corresponding with Ball’s (1951) three step movement described for middle
depths in the North Sea.
The only factor which the day and niight migrations could be corre-
lated with was the light intensity.
Stomach contents was found in the afternoon, whereas a sample of
herring taken at 730 GMT, at sunrise, had empty stomachs only. The
herring feed was composed of Acartia sp. besides some few Temora longi-
cornis. Acartia longiremis and Acartia Clausii were dominating in the
plankton samples, ohiefly females with egg sacks.
BÓKMENTIR
Anon. Report on the Meeting on Scale and Otolith typing and other
Meth-ods in Atlanto-Scandian Herring Research. ICES CM. 1962 H: 1.
Balls, R. Environmental Changes in Herring Behaviour; a Theory of Light
Avoidance, as suggested by Echo-sounding in the North Sea. Journ. du
Cons. Int. pour l’Explor. de la Mer 17, 3, 1951.
Blaxter, J. H. S. Effect of Ohange of light Inten9Íty on Fish. ICNAF
spec. Publ. nr. 6, 1965.
Blaxter, J. H. S. & Parrisb, B. B. The Importance og Light in Shoaling,
Avoidance of Nets and vertical Migration by Herring. Journ. du Cons.
Int. pour l’Explor. de la Mer 30, 1, 1965.
Brawn, V. M. Seasonal and Diurnal vertical Distribution of Herring
(Clupea harengus, L.) in Passamaquoddy Bay. Journ. Fish. Res. Bd.
Canada, 17, 1960.