Prey-type-dependent foraging of young-of-the-year fish in turbid and humic environments
Författare
Summary, in English
Fish, which are generally visual foragers, experiences reduced reaction distance in visually degraded environments, which has consequences for encounter rates with prey. Small prey is detected at shorter distances than larger prey, and piscivores are therefore predicted to be more strongly affected by visual degradation. In experiments, roach (Rutilus rutilus) were fed two plankton prey types and pike (Esox lucius) were fed Daphnia and larval roach, in clear water, algal turbid water and water coloured brown by dissolved organic matter (DOM). Planktivorous foraging in roach was not affected by visual degradation, while pike foraging on both Daphnia and larval roach was. Pike showed increased reaction distance to Daphnia in visually degraded water, while it was severely reduced with roach as prey even if the visual range was not reduced below pike reaction distances in clear water. Pike foraging on Daphnia was not affected, but when foraging on roach, the reduced search efficiency was counteracted by increased attack rates. However, there was no increase in movement and no difference between turbid and DOM treatments. Effects on piscivores will likely become more pronounced at later life stages as prey size and the reliance on long-distance detection increases at the same time as changing climatic conditions may further deteriorate the visual conditions in future.
Avdelning/ar
Publiceringsår
2012
Språk
Engelska
Sidor
461-468
Publikation/Tidskrift/Serie
Ecology of Freshwater Fish
Volym
21
Issue
3
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Wiley-Blackwell
Ämne
- Electrical Engineering, Electronic Engineering, Information Engineering
- Ecology
Nyckelord
- turbidity
- humic water
- foraging
- prey size
- juvenile fish
Status
Published
Forskningsgrupp
- Aquatic Ecology
ISBN/ISSN/Övrigt
- ISSN: 0906-6691