Seasonal Buoyancy Changes in Atlantic Salmon ( Salmo salar ) Parr and Smolt
A population of yearling Atlantic salmon parr was held in the laboratory from July to June in a negligible current at seasonal temperatures and photoperiods. Indirect measurements of swimbladder volume (pressure of neutral buoyancy) were made monthly on groups of 14–20 fish held for 24 hr either in...
| Published in: | Journal of the Fisheries Research Board of Canada |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1969
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f69-194 http://www.nrcresearchpress.com/doi/pdf/10.1139/f69-194 |
| Summary: | A population of yearling Atlantic salmon parr was held in the laboratory from July to June in a negligible current at seasonal temperatures and photoperiods. Indirect measurements of swimbladder volume (pressure of neutral buoyancy) were made monthly on groups of 14–20 fish held for 24 hr either in still water or in a current (0.13 m/sec).Parr were consistently less buoyant in the current than in still water. However, seasonal changes occurred, particularly in the current. For parr in a current, buoyancy was lowest in early winter but increased throughout the spring until the parr–smolt transformation, when smolts in the current were just as buoyant as smolts in still water. The seasonal development of smolt buoyancy in a current was related to body size and water temperature but did not seem to be affected by photoperiod.The seasonal changes in swimbladder volume were not significantly correlated with tissue density (density of the gas-free fish), which in turn was not significantly correlated with the level of ether-extractable fat. However, the level of ether-extractable fat was significantly correlated with the coefficient of condition. At parr–smolt transformation, tissue density, level of ether-extractable fat, and coefficient of condition decreased sharply. |
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