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Prey-type-dependent foraging of young-of-the-year fish in turbid and humic environments

Author:
  • Mikael Jönsson
  • Lynn Ranåker
  • P. Anders Nilsson
  • Christer Brönmark
Publishing year: 2012
Language: English
Pages: 461-468
Publication/Series: Ecology of Freshwater Fish
Volume: 21
Issue: 3
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract 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.

Keywords

  • Electrical Engineering, Electronic Engineering, Information Engineering
  • Ecology
  • turbidity
  • humic water
  • foraging
  • prey size
  • juvenile fish

Other

Published
  • ISSN: 0906-6691
Christer Brönmark
E-mail: christer [dot] bronmark [at] biol [dot] lu [dot] se

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Division aquatic ecology

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Professor

Aquatic Ecology

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Professor

Division aquatic ecology

+46 46 222 37 02

+46 73 081 55 48

E-C125

Sölvegatan 37, Lund

50

Research group

Aquatic Ecology

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