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The relative importance of fish predation and excretion effects on planktonic communities

Attayde, J L and Hansson, Lars-Anders LU (2001) In Limnology and Oceanography 46(5). p.1001-1012
Abstract
The effects of planktivorous fish on lower trophic levels through predation on zooplankton and nutrient excretion were experimentally separated and their relative importance quantified in a eutrophic humic lake. The experiment was performed in 12 enclosures (3 mi), which initially were identical with respect to all components except fish. At the start of the experiment, caged fish not able to feed on zooplankton were added to four of the enclosures (excretion treatment), and free swimming fish to four enclosures (excretion plus predation treatment). Four enclosures were left as controls. Samples for nutrients and all major groups of organisms from bacteria to zooplankton were taken after 14 and 28 d. The effect sizes of fish excretion and... (More)
The effects of planktivorous fish on lower trophic levels through predation on zooplankton and nutrient excretion were experimentally separated and their relative importance quantified in a eutrophic humic lake. The experiment was performed in 12 enclosures (3 mi), which initially were identical with respect to all components except fish. At the start of the experiment, caged fish not able to feed on zooplankton were added to four of the enclosures (excretion treatment), and free swimming fish to four enclosures (excretion plus predation treatment). Four enclosures were left as controls. Samples for nutrients and all major groups of organisms from bacteria to zooplankton were taken after 14 and 28 d. The effect sizes of fish excretion and predation were calculated for each variable. Our results suggest that in eutrophic lakes fish predation on zooplankton may be more important than nutrient excretion by fish for the structure and dynamics of planktonic communities. Fish predation on zooplankton was the most important mechanism accounting for fish effects on nutrient concentrations in the water, on phytoplankton biovolume, on rotifers and total zooplankton biomass, as well as on protozoan densities. However our results suggest that nutrient excretion by fish may have important indirect effects on zooplankton. Hence, the effects of plankrivorous fish through both predation on zooplankton and nutrient excretion act in concert acid may be quantitatively important to shape the structure and dynamics of planktonic communities. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Limnology and Oceanography
volume
46
issue
5
pages
1001 - 1012
publisher
ASLO
external identifiers
  • scopus:0034923828
ISSN
1939-5590
language
English
LU publication?
yes
id
6b37c841-9064-4398-b5c6-d1f3f9a45f5c (old id 146638)
alternative location
http://www.aslo.org/lo/toc/vol_46/issue_5/1001.pdf
date added to LUP
2007-06-28 12:17:34
date last changed
2018-01-07 09:43:55
@article{6b37c841-9064-4398-b5c6-d1f3f9a45f5c,
  abstract     = {The effects of planktivorous fish on lower trophic levels through predation on zooplankton and nutrient excretion were experimentally separated and their relative importance quantified in a eutrophic humic lake. The experiment was performed in 12 enclosures (3 mi), which initially were identical with respect to all components except fish. At the start of the experiment, caged fish not able to feed on zooplankton were added to four of the enclosures (excretion treatment), and free swimming fish to four enclosures (excretion plus predation treatment). Four enclosures were left as controls. Samples for nutrients and all major groups of organisms from bacteria to zooplankton were taken after 14 and 28 d. The effect sizes of fish excretion and predation were calculated for each variable. Our results suggest that in eutrophic lakes fish predation on zooplankton may be more important than nutrient excretion by fish for the structure and dynamics of planktonic communities. Fish predation on zooplankton was the most important mechanism accounting for fish effects on nutrient concentrations in the water, on phytoplankton biovolume, on rotifers and total zooplankton biomass, as well as on protozoan densities. However our results suggest that nutrient excretion by fish may have important indirect effects on zooplankton. Hence, the effects of plankrivorous fish through both predation on zooplankton and nutrient excretion act in concert acid may be quantitatively important to shape the structure and dynamics of planktonic communities.},
  author       = {Attayde, J L and Hansson, Lars-Anders},
  issn         = {1939-5590},
  language     = {eng},
  number       = {5},
  pages        = {1001--1012},
  publisher    = {ASLO},
  series       = {Limnology and Oceanography},
  title        = {The relative importance of fish predation and excretion effects on planktonic communities},
  volume       = {46},
  year         = {2001},
}