53 research outputs found
Growth of juvenile halibut (Hippoglossus hippoglossus L.) in captivity
The growth and substrate preference of collected wild juvenile
halibut under culture conditions were investigated. The size of
the collected fish conformed well with year class data from earlier
studies.
Halibut growth in nature is slower than for i.e. cultured salmon
up to the III-group. The present study showed, however, that halibut
can grow much faster in culture than what is normal in nature.
The substrate studies were contradictory in terms of growth and
will have to be extended. The fish without substrate did, however,
develope a dark coloration on the underside
An automatic feeding system for culturing rotifers with dry feed
An automatic feed distribution system for culturing rotifers
is described and discussed. The system has been successfully
used at the Austevoll Marine Aquaculture Station for 3 years
Dynamics of wintering Norwegian spring-spawning herring at the entrance to Tysfjorden, December 1996
The entrance region to Tysfjorden was acoustically surveyed a total of eleven times
during the December 1996 abundance survey of the spawning stock of Norwegian
spring-spawning herring (Clupea harengus). The observations are summarized
through maps of the distribution, vertical sections, and statistical measures of acoustic
density in each of two strata. Experimental variograms are modeled, yielding
parameter values that summarize the major properties of aggregation. The collective
measures of density and aggregation portray a highly dynamic situation with strong
diel variation but a general persistence of the fish distribution over the eleven days of
its repeated observation
The effect of shading in pen rearing of Atlantic salmon (Salmo salar)
A full scale pen rearing experiment with covers to reduce
illumination was carried out. No significant effects were
observed on growth, mortality, ectoparasite infection,
maturation or net pen fouling
Day / night variation in fish directivity in the trawl opening
Still photographs of fish in the mouth area of a bottom trawl were taken by a downwards-oriented
automated strobe camera mounted near the headrope. Fish angles relative to the
towing direction were measured. Fish were significantly less polarized by night than by day,
and in the daytime photographs less polarization was seen at low fish densities than at higher.
The results are discussed with regard to fish herding patterns and potential escapement
beneath the fishing line of a trawl
Seal investigations in the North Atlantic in 1974
Accounts are given of weather and ice conditions, the distribution of seals and of sampling of harp and hooded seals at Newfoundland-Labrador, in the West Ice (at Jan Mayen), in the East Ice (in the Eastern Barents Sea) and in the Denmark trait. A few provisional results of age analysis are given. Some observations from the coast of Norway suggest increasing numbers of local common and grey seals
Seal investigations in the North Atlantic in 1974
Accounts are given of weather and ice conditions, the distribution of seals and of sampling of harp and hooded seals at Newfoundland-Labrador, in the West Ice (at Jan Mayen), in
the East Ice (in the Eastern Barents Sea) and in the Denmark
Strait. A few provisional results of age analysis are given. Some
observations from the coast of Norway suggest increasing numbers
of local common and grey seals
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