Feeding Response of Atlantic Salmon (Salmo salar) Alevins in Flowing and Still Water

Atlantic salmon (Salmo salar) alevins presented with lake zooplankton in still water readily consumed prey items, but only if the prey were nearby and moving. Feeding was initiated from the bottom or from midwater, but no search or pursuit behavior was noted. Stomach analyses of alevins exposed to lake zooplankton assemblages for 3 h in still and flowing (7.2 cm∙s−1) water revealed that the two groups consumed similar diets, but that the still-water group had a greater total food consumption. We conclude that for alevins to feed successfully, food need not be carried in a water current, but that motion of the prey is necessary. This motion can be provided by water current or by the prey. The role of prey motility in the feeding of young salmonids is briefly discussed. Key words: Atlantic salmon, alevins, feeding, water current

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The effect of porcine somatotropin on growth, and survival in seawater of Atlantic salmon (Salmo salar) parr

Canadian Journal of Zoology ◽

10.1139/z76-060 ◽

1976 ◽

Vol 54 (4) ◽

pp. 531-535 ◽

Cited By ~ 114

Author(s):

M. P. Komourdjian ◽

R. L. Saunders ◽

J. C. Fenwick

Keyword(s):

Growth Hormone ◽

Atlantic Salmon ◽

Salmo Salar ◽

Growth Hormone Treatment ◽

Hormone Treatment ◽

Control Fish ◽

Growth And Survival ◽

Atlantic Salmon Salmo Salar ◽

Porcine Somatotropin

The effects of porcine growth hormone on growth and salinity tolerance were studied in Atlantic salmon (Salmo salar) parr. Fish were held in freshwater at 11.5 °C during June and July under a photoperiod with light to dark periods opposite to the prevailing natural conditions. Fish treated with 1.0 μg/g body weight of growth hormone preparation on alternate days were significantly longer (P <.05), after 4 weeks, than placebo-injected controls. All hormone-injected fish survived transfer to seawater, 30‰ salinity. But under the same conditions, placebo-injected control fish showed a high mortality rate. Growth-hormone treatment caused a darkening of fin margins and a yellowing of the operculae and fin surfaces. The silvering which normally accompanies smoltification was not observed. The role of growth hormone in eliciting these actions and its possible role in the parr–smolt transformation are discussed.

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Role of Fat Stores in the Maturation of Male Atlantic Salmon (Salmo salar) Parr

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f91-052 ◽

1991 ◽

Vol 48 (3) ◽

pp. 405-413 ◽

Cited By ~ 216

Author(s):

D. K. Rowe ◽

J. E. Thorpe ◽

A. M. Shanks

Keyword(s):

Atlantic Salmon ◽

Salmo Salar ◽

Gonadosomatic Index ◽

Total Lipids ◽

Fat Accumulation ◽

Atlantic Salmon Salmo Salar ◽

Mesenteric Fat ◽

Fat Stores

We provide evidence that in male Atlantic salmon (Salmo salar) parr, maturation is suppressed when mesenteric fat fails to exceed an undefined level by May. In nonmaturing parr the postwinter increase in total lipids began in May, while the mesenteric store started filling in June. However, in male parr which would have matured, total lipids started increasing a month earlier, in April, and the mesenteric store started filling in May. Consequently, maturing male parr had significantly more mesenteric fat than nonmaturing fish by June. Mesenteric fat is needed for maturation. Levels continued to increase in nonmaturing parr during autumn months, but had declined in maturing parr by September. This depletion of mesenteric fat in maturing males coincided with increases in the gonadosomatic index from 0.05 to 10% and with reductions in both feeding and growth. Fasting during spring months delayed increases in total lipids and fat accumulation into the mesenteric store until June and suppressed maturation rates of male parr. The internal decision to suppress maturation is therefore dependent on mesenteric fat levels increasing in May. However, this requires the prior replenishment of other stores in April. A model is proposed to explain the physiological link between fat accumulation during spring and the initiation of maturation.

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