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The reaction of young coho Oncorhynchus kisutch to declining oxygen levels during long‐term exposure
Author(s) -
Waller By U.,
Black E.,
Burt D.,
Groot C.,
Rosenthal H.
Publication year - 2000
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1046/j.1439-0426.2000.00168.x
Subject(s) - oncorhynchus , biology , term (time) , fishery , zoology , fish <actinopterygii> , physics , quantum mechanics
The respiration of coho salmon, Oncorhynchus kisutch , weighing between 20 and 45 g was measured at gradually declining oxygen levels and at temperatures ranging between 14 and 17 °C. The maximum and minimum oxygen concentrations tested were 235 and 41 μmol/L, respectively. Respiration rates were measured for 24 h at 235 μmol/L before the oxygen concentration was lowered stepwise to 157 and 81 μmol/L. In one single trial, the oxygen level was lowered to 66, 53, and 41 μmol/L. Respiration was highly variable in time. Peak activities always occurred during the night. The standard metabolic rate at normoxic conditions was estimated to be around 4 μmol oxygen/g/h. The highest rates reached values close to 15 μmol oxygen/g/h. At reduced oxygen levels the standard oxygen demand slightly increased to 4.5 μmol oxygen/g/h, indicating a higher demand for vital metabolic functions. Due to the decrease of swimming activity, the maximum oxygen uptake rates dropped to < 8 μmol oxygen/g/h below 81 μmol/L oxygen concentration. Under long‐term conditions, physiological and behavioural adaptations play an important role for survival and need to be considered for the design and operation of fish farm facilities.