Kock, R.P. (2000) Predatie van vissen op de migrerende bivalve Macoma balthica. Master's Thesis / Essay, Biology.
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Abstract
Macoma baithica is one of the most common species in the Wadden Sea. In the summer the post-larvae migrate to the high tides. The life conditions on the high tides are more favourable than on the low tides for the post-larvae. The juveniles migrate in their first winter to the low tides. If they do not migrate they can be an easy prey for predators, such as birds and shrimps. Leaving the sediment can also be very dangerous for Macoma baithica. They can become an easy prey for different animals, such as crabs, shrimps and fishes. Lab experiments were done to investigate the predation risk of Macoma baithica when they leave the sediment in the present of fishes. Experiments were done in daylight and in the dark. Post-larvae and juvenile Macoma 's were used. Three different species of fishes were used. Pomatoschistus minutes and Pleuronectes platessa were used as predators for the post-larvae Macoma 's and Dicentrarchus labrax was used as predator for the juveniles. No Macoma baithica was eaten during the experiments with Dicentrarchus labrax. There was no significant difference (P>O.05) in the results where Pomatoschistus minutus was used as predator. A significant difference (P<O.05) was found in the experiments using Pleuronectes platessa as predator. Also a significant difference was found between the experiments done in daylight and in the dark. More Macoma baithica was eaten in the daylight than in the dark by Pleuronectes platessa. It was concluded that it is dangerous for Macoma baithica to migrate. In the presence of a visually hunting predator it is more favourable to migrate when it is dark. It was also confirm that the post-larvae produce a byssus thread and thus they have also an active migration.
| Item Type: | Thesis (Master's Thesis / Essay) |
|---|---|
| Degree programme: | Biology |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 15 Feb 2018 07:31 |
| Last Modified: | 15 Feb 2018 07:31 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/9208 |
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