Effect of hunger on the daily pattern of feeding rates in juvenile pink salmon, Oncorhynchus gorbuscha Walbaum
Juvenile pink salmon, Oncorhynchus gorbuscha , in two test groups of differing hunger level fed continuously on live copepods, maintained at high densities, throughout 12 h feeding periods in the laboratory. Analysis of video films showed that mean feeding rates were initially (first 10 min) between...
| Published in: | Journal of Fish Biology |
|---|---|
| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1981
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/j.1095-8649.1981.tb05811.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1981.tb05811.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1981.tb05811.x |
| Summary: | Juvenile pink salmon, Oncorhynchus gorbuscha , in two test groups of differing hunger level fed continuously on live copepods, maintained at high densities, throughout 12 h feeding periods in the laboratory. Analysis of video films showed that mean feeding rates were initially (first 10 min) between 51.5 and 63.8 prey‐capture attempts (snaps) fish ‐1 10 min ‐1 , but declined abruptly with increasing satiation to relatively constant levels of about 5.0 and 8.0 snaps fish ‐1 10 min ‐1 , which were maintained during the subsequent 11 h of feeding. The data suggests that after the initial filling of their stomachs with food, juvenile pink salmon keep their stomachs full by feeding at a rate that balances the gastric evacuation rate of 18.6 mg prey h ‐1 at 11° C. Less than 15% of the fish's stomach contents need be evacuated apparently for spontaneous feeding to resume or occur. Increased hunger level (by increasing a pre‐test food deprivation period from 24 to 72 h) resulted in fish increasing their average feeding rate and thus their ration consumed from 23.6 to 39.8% dry body weight per 12 h. |
|---|