Migration of farmed adult Atlantic salmon with and without olfactory sense, released on the Norwegian coast
The dispersal and migration of farmed Atlantic salmon, Salmo salar , allowed to escape during the summer was studied. Three groups of 4–year–old fish of the River Imsa stock were released in coastal waters off south‐western Norway: one group, with functional olfactory organs, was released at a fish...
| Published in: | Journal of Fish Biology |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1987
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/j.1095-8649.1987.tb05800.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1987.tb05800.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1987.tb05800.x |
| Summary: | The dispersal and migration of farmed Atlantic salmon, Salmo salar , allowed to escape during the summer was studied. Three groups of 4–year–old fish of the River Imsa stock were released in coastal waters off south‐western Norway: one group, with functional olfactory organs, was released at a fish farm 4 km away from the R. Imsa; two other groups, one with transected olfactory nerves and the other with functional olfactory organs, were released in the sea 90 km from the R. Imsa. To compare them with the migration pattern of reared, large smolts of the Imsa stock, a group of 3 + smolts was released in the R. Imsa. Adults of salmon released as 3–year–old smolts homed with high precision to the R. Imsa. Four– year–olds released in the sea were recaptured in the fjord and in the coastal current, the majority north of the places of release. Immatures migrated to feeding areas in the North Atlantic. Matures seemed to enter rivers at random when ready to spawn. There was no difference in migration pattern between anosmics and controls. The olfactory sense was not mandatory for entering fresh water. The results indicate that the homing behaviour of Atlantic salmon is not a direct consequence of a single imprinting of the smolts, and that there is not a direct genetic link for return to a particular river. The present results support the sequential imprinting hypothesis proposed by Harden Jones (1968). |
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