Foraging efficiency and prey selectivity in a visual predator: differential effects of turbid and humic water
(2013) In Canadian Journal of Fisheries and Aquatic Sciences 70(12). p.1685-1690- Abstract
- Predators exert strong regulating forces on lower trophic levels through predation. As most fish are visual foragers, visual conditions in the water may alter the strength of this regulation. We evaluated effects of turbidity and humic water on foraging efficiency and prey-size selectivity in Northern pike (Esox lucius) feeding on roach (Rutilus rutilus). Encounter rates decreased in both turbid and humic water but were not counteracted by increased searching activity. Capture success was unaffected by turbidity but was nonlinearly affected by humic water by being high in clear and highly humic water but low in less humic water. In highly humic water, the visual range approached pike's strike distance and, together with its cryptic... (More)
- Predators exert strong regulating forces on lower trophic levels through predation. As most fish are visual foragers, visual conditions in the water may alter the strength of this regulation. We evaluated effects of turbidity and humic water on foraging efficiency and prey-size selectivity in Northern pike (Esox lucius) feeding on roach (Rutilus rutilus). Encounter rates decreased in both turbid and humic water but were not counteracted by increased searching activity. Capture success was unaffected by turbidity but was nonlinearly affected by humic water by being high in clear and highly humic water but low in less humic water. In highly humic water, the visual range approached pike's strike distance and, together with its cryptic colours, pike may have initiated its attack before the prey detected it, limiting the possibility for prey evasive manoeuvres. Prey-size selectivity towards small prey in clear water disappeared in turbid water but was maintained in humic water. Owing to its optical properties, turbidity degrades the quality of the visual information more through scattering than humic water does through absorption. We show that the effect of visual degradation on foraging depends on the cause of visual degradation, which has not previously been acknowledged in the visual foraging literature. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4272774
- author
- Jönsson, Mikael LU ; Ranåker, Lynn LU ; Nilsson, Anders LU and Brönmark, Christer LU
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Canadian Journal of Fisheries and Aquatic Sciences
- volume
- 70
- issue
- 12
- pages
- 1685 - 1690
- publisher
- Canadian Science Publishing, NRC Research Press
- external identifiers
-
- wos:000328273100003
- scopus:84888354391
- ISSN
- 1205-7533
- DOI
- 10.1139/cjfas-2013-0150
- language
- English
- LU publication?
- yes
- id
- 8fb1274a-9dd4-46e9-9c0d-728f4254a355 (old id 4272774)
- date added to LUP
- 2016-04-01 10:28:40
- date last changed
- 2024-04-21 13:29:34
@article{8fb1274a-9dd4-46e9-9c0d-728f4254a355, abstract = {{Predators exert strong regulating forces on lower trophic levels through predation. As most fish are visual foragers, visual conditions in the water may alter the strength of this regulation. We evaluated effects of turbidity and humic water on foraging efficiency and prey-size selectivity in Northern pike (Esox lucius) feeding on roach (Rutilus rutilus). Encounter rates decreased in both turbid and humic water but were not counteracted by increased searching activity. Capture success was unaffected by turbidity but was nonlinearly affected by humic water by being high in clear and highly humic water but low in less humic water. In highly humic water, the visual range approached pike's strike distance and, together with its cryptic colours, pike may have initiated its attack before the prey detected it, limiting the possibility for prey evasive manoeuvres. Prey-size selectivity towards small prey in clear water disappeared in turbid water but was maintained in humic water. Owing to its optical properties, turbidity degrades the quality of the visual information more through scattering than humic water does through absorption. We show that the effect of visual degradation on foraging depends on the cause of visual degradation, which has not previously been acknowledged in the visual foraging literature.}}, author = {{Jönsson, Mikael and Ranåker, Lynn and Nilsson, Anders and Brönmark, Christer}}, issn = {{1205-7533}}, language = {{eng}}, number = {{12}}, pages = {{1685--1690}}, publisher = {{Canadian Science Publishing, NRC Research Press}}, series = {{Canadian Journal of Fisheries and Aquatic Sciences}}, title = {{Foraging efficiency and prey selectivity in a visual predator: differential effects of turbid and humic water}}, url = {{http://dx.doi.org/10.1139/cjfas-2013-0150}}, doi = {{10.1139/cjfas-2013-0150}}, volume = {{70}}, year = {{2013}}, }