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Demand‐feeding behaviour and diel pattern of feeding activity in Oncorhynchus mykiss held under different photoperiod regimes
Author(s) -
Boujard T.,
Leatherland J. F.
Publication year - 1992
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1992.tb02603.x
Subject(s) - photoperiodism , dusk , diel vertical migration , biology , zoology , body weight , weight gain , food intake , fishery , ecology , botany , endocrinology
Demand‐feeding behaviour was studied in Oncorhynchus mykiss held at 7–10°C in groups of 30 individuals, under a 16:8, 12:12 or 8 : 16 light : dark regime, using self‐feeders connected to a computer. The daily food demand was variable between tanks from 1.5 to 5% of the body weight, the specific growth rate ranged between 1.4 and 2.6% of body weight increase per day, and the feed: gain ratio ranged between 0.84 and 3.17, regardless of the photoperiod length. More than 98% of the feeding demand occurred during the photophase, regardless of the photoperiod, with a main peak at dawn and an occasional peak at dusk.