| dc.description.abstract | In 1966-1969 euphausiids (krill) were sampled in some fjords in Western Norway.
Drained volumes of krill constituted 13-82 ml, exceptionally 100-167 ml per 1 000 m3.
Meganyctiphanes norvegica, Thysanoessa inermis and T. raschii dominated in the order
mentioned. During the day, Thysanoessa spp. kept at higher levels than M. norvegica;
during the night T. raschii and part of the stock of M. norvegica accumulated close to
the surface. M. norvegica had densities of 0.1-1 specimens per m3, but higher concentrations
were induced in spring with electric light. Vertical layering was observed
with large specimens at deeper levels. M. norvegica spawned in March-June one
year old. Part of the stock survived a second spawning, a few lived for nearly three
years. One year olds measured 22-31 mm (average 27 mm), two year olds 32-41 mm
(average 37 mm) and three year olds 43-47 mm.
In T. inermis a maximum of 1-4 specimens per m3 occurred in the upper 10-50
m during the night in January-February and October-November, at other times
only 0.05-0.3 specimens per m3. T. inermis is annual in the area, spawning in March-
June, with maximum in April. Length of one year olds was 17-20 mm, single second
year survivors 26 mm. The two-spined form was observed in 1-3 % of the stock.
T. raschii had maximum densities of 3.5 and 5.0 specimens per m3 in the upper
10 m in February and November respectively, at other times figures were very low.
T. raschii is annual; spawning occurs in April-June, starting somewhat later than in
T. inermis. Growth and length distributions are as a rule similar to those of T. inermis. | |
