Significance of the Timing of Initial Feeding in Hatchery Rainbow Trout, Salmo gairdneri

1976 ◽  
Vol 33 (9) ◽  
pp. 1914-1921 ◽  
Author(s):  
Timothy K. Twongo ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Abdominal Cavity ◽  
Food Presentation ◽  
Ingestive Behavior ◽  
Salmo Gairdneri ◽  
Food Ingestion ◽  
Young Fish ◽  
Subsequent Growth ◽  
Exogenous Feeding ◽  
Hatchery Fish

The age of initial food ingestion and the influence of age at initial food presentation on alevin food intake, survival, and subsequent growth were determined for rainbow trout, Salmo gairdneri. Alevins did not show any ingestive behavior nor was any food found in their gut, before initiation of swim-up. The withholding of food from the young fish for some time after swim-up did not impair their ability to learn to feed. Further, the most satisfactory time to initiate exogenous feeding of hatchery fish is when yolk reserves have been completely absorbed, bearing in mind that a considerable quantity of yolk may yet remain in the abdominal cavity after the externally visible yolk sac has disappeared.This study contradicts the hypothesis that delayed feeding of young rainbow trout causes or enhances the likelihood of nonfeeding.

Ontogeny of feeding behaviour in hatchery-reared rainbow trout, Salmo gairdneri Richardson

1980 ◽  
Vol 58 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Timothy K. Twongo
Keyword(s):  
Rainbow Trout ◽  
Feeding Behaviour ◽  
Feeding Activity ◽  
Artemia Salina ◽  
Artificial Feeding ◽  
Food Type ◽  
Salmo Gairdneri ◽  
Agonistic Behaviour ◽  
Exogenous Feeding ◽  
First Feeding

Development of feeding behaviour in young rainbow trout, Salmo gairdneri, from "swim-up" to day 57 after hatch at 8.5 °C is described relative to food type (live Artemia salina or dry trout ration) and water flow (current or no current). Earliest signs of feeding behaviour appear during the process of swim-up at days 27 to 29, with the movement of the eyes to fixate particles and the beginning of a snap response which intensifies within 2 days. Initially the alevins are nonselective between food and inert targets, but by about day 25 at the test temperature they have become able to discriminate food from nonfood items, and show a marked increase in exogenous feeding activity. The timing, which will differ at different rearing temperatures, coincides approximately with final absorption of the visible yolk sac and follows disappearance of the oesophageal plug by about 10 days. This would seem to be the best time to initiate artificial feeding of hatchery-reared alevins, with the fish showing a preference for ingestion of live food (shrimp nauplii) over dry rations. Despite evident behavioural differences in current and no-current conditions this factor had little effect on timing or ultimate success of first feeding. Failure of some alevins to begin feeding, or feed adequately for survival, is associated with the agonistic behaviour of more aggressive siblings.

Temperature Selection of Rainbow Trout (Salmo gairdneri) Fingerlings in Vertical and Horizontal Gradients

1971 ◽  
Vol 28 (11) ◽  
pp. 1801-1804 ◽  
Author(s):  
R. W. McCauley ◽  
W. L. Pond
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Temperature Preference ◽  
Temperature Selection ◽  
Horizontal Gradients ◽  
Significant Difference ◽  
Preferred Temperatures ◽  
Laboratory Investigations ◽  
Horizontal Temperature Gradients ◽  
Selection Of

Preferred temperatures of underyearling rainbow trout (Salmo gairdneri) were determined in both vertical and horizontal temperature gradients. No statistically significant difference was found between the preferred temperatures by the two different methods. This suggests that the nature of the gradient plays a lesser role than generally believed in laboratory investigations of temperature preference.

scholarly journals The Distribution of 35S-Sulfadiazine and 14G-Trimethoprim in Rainbow Trout, Salmo Gairdneri

1979 ◽  
Vol 20 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Torill Bergsjø ◽  
Inger Nafstad ◽  
Kristian Ingebrigtsen
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri
Sign in / Sign up

Export Citation Format

Share Document