|dc.contributor.author||Solberg, Tor Sverre||
|dc.description.abstract||Growth, oxygen uptake, swimming activity, feeding ability
and energy content were investigated in cod larvae from
several groups under different experimental conditions.
At yolk absorption the larvae consumed 0.090-0.120 ul O2/larva/hour
depending on the larval group examined. The
larval energy consumption either measured as oxygen uptake or
calculated from larval weight decrement, was of the same
magnitude. The oxygen uptake was 20-30% higher under 100 lux
illumination than in darkness, a difference which was of the
same magnitude (20%) as the difference in weight decrement
between larvae held at a constant 500 lux and larvae held in
constant darkness. Light-adapted larvae showed a 6-10 times
higher swimming frequency (bursts of swmming per min) than
The overall utilization of yolk for somatic growth varied
between 65 and 70 % depending on the larval group examined.
The utilization seemed independant of temperature and light
intensity when these parameters were kept within the natural
range observed during hatching in the Lofoten area.
The specific energy content of eggs and larvae showed a
steady decrease through the experimental period from 5.8 cal/
mq ash free dry weight in newly fertilized eggs to 4.8 cal/
mg ash free dry weight in larvae 12 days after hatchlng.
The larvae showed maximum swimming speeds at days 5, 6 and
7 post-hatching (10-20 cm/min). There was a significant
correlation between mean swimming speed (cm/min) and mean
swimming frequency (number of swimming bursts/min) throughout
the experimental period.
The larvae showed maximum feeding success (22%) at day 7
The results are discussed in relation to larval prey
density requirements at the onset of feeding.||en
|dc.title||Growth, energy consumption and prey density requirements in first feeding larvae of cod (Gadus morhua L.). In: The propagation of cod Gadus morhua L.: an international symposium, Arendal, 14 - 17 June 1983||en