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Demand-feeding activity of Rainbow Trout (Oncorhynchus mykiss) in raceways

journal contribution
posted on 2023-05-17, 19:49 authored by Heydarnejad, MS, Gary PurserGary Purser
Demand-feeding activity of rainbow trout (Oncorhynchus mykiss) in raceways was studied. The raceways were positioned within a re-circulating system and each was supplied with filtered and aerated freshwater. The raceways were divided equally into 4 sections and respectively numbered from section 1 (most upstream, the location of the water inlet) to section 4 (most downstream, the location of the water outlet). In order for the fish to be visually identified, they were tagged individually, by means of the button technique. Self-feeding activity was defined as a number of trigger actuations by the fish, recorded by the computer. The Chronolab and Citech programs were used for data acquisition and presentation of self-feeding activity as actograms and periodograms. The results showed that there were three fish that accounted for more than 89% of combined total actuations of the two demand-feeders (up-and downstream), namely W/B (White/Black), W/R (White/Red) and W/W (White/White) and the contribution of the fish W/B in the two demand-feeders was far greater than the fish W/R or W/W. In addition, by restricting the times during which food was available, demand-feeding activity of the fish became more or less synchronized to the mealtimes. This investigation suggests that when demand-feeders are used individual rainbow trout are able to learn to use the feeders, but when kept in groups, only a few individuals can operate the system (due to the development of dominance hierarchy).


Publication title

World Journal of Zoology








Institute for Marine and Antarctic Studies


International Digital Organization for Scientific Information (I D O S I)

Place of publication

United Arab Emirates

Rights statement

Copyright 2013 IDOSI Publications

Repository Status

  • Restricted

Socio-economic Objectives

Fisheries - aquaculture not elsewhere classified

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