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Diel feeding chronology, gastric evacuation and estimated daily ration of juvenile coho salmon, Oncorhynchus kisutch (Walbaum), in the coastal marine environment
Author(s) -
Brodeur R. D.,
Pearcy W. G.
Publication year - 1987
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.1095-8649.1987.tb05252.x
Subject(s) - diel vertical migration , oncorhynchus , juvenile , biology , morning , fishery , zoology , stomach , chinook wind , body weight , fish <actinopterygii> , ecology , endocrinology , botany , biochemistry
The feeding periodicity of juvenile coho salmon, Oncorhynchus kisutch , was examined from stomach collections taken during five sampling periods in coastal waters off Oregon. Significant differences in stomach content weight were found between several consecutive 3‐hour periods, with peak fullness occurring in early morning and around dusk. The rates of gastric evacuation of euphausiid meals were measured in the laboratory at two temperatures. The decline in stomach contents was best described by an exponential model: 90% evacuation of the wet weight contents required an estimated 28.4 and 18.1 h at 11.4 and 13.7° C, respectively. The method of Elliott & Persson was used to estimate a daily ration of 2.4 and 3.7% of the wet body weight at the two temperatures.