Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River
Abstract Physical conditions are usually considered pre‐eminent in controlling river plankton, but biotic interactions may be important in slackwater areas. To begin testing this general hypothesis, we conducted a 12‐day, predator–prey experiment in 3500 litre mesh enclosures in a slackwater area of...
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crwiley:10.1002/rra.703 2024-09-30T14:46:18+00:00 Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River Thorp, James H. Casper, Andrew F. 2003 http://dx.doi.org/10.1002/rra.703 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Frra.703 https://onlinelibrary.wiley.com/doi/pdf/10.1002/rra.703 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor River Research and Applications volume 19, issue 3, page 265-279 ISSN 1535-1459 1535-1467 journal-article 2003 crwiley https://doi.org/10.1002/rra.703 2024-09-17T04:43:29Z Abstract Physical conditions are usually considered pre‐eminent in controlling river plankton, but biotic interactions may be important in slackwater areas. To begin testing this general hypothesis, we conducted a 12‐day, predator–prey experiment in 3500 litre mesh enclosures in a slackwater area of the St. Lawrence River using planktivorous, juvenile yellow perch ( Perca flavescens ) and Dreissena mussels. Results generally supported our hypotheses that: (1) perch would directly suppress large zooplankton via predation but benefit microzooplankton through indirect interactions; and (2) dreissenids would directly depress rotifer densities via predation and have indirect negative effects on macrozooplankton. Based on gut contents of experimental fish, cladocera were the principal prey of smaller yellow perch ( c . 46–50 mm), followed by copepods, ostracods, and rotifers. Larger juvenile perch ( c . 67–73 mm) fed almost exclusively on copepods and ostracods. Densities of calanoid copepodids, nauplii, and some cyclopoid copepods ( Diacyclops thomasi ) were significantly depressed by perch, and adult Eurytemora affinis (99% of adult calanoids) essentially disappeared from fish enclosures. Despite being a favourite prey item of small perch, densities of the small cladoceran Bosmina ( Sinobosmina ) spp. were significantly higher when fish were present (150% greater than control densities on Day 12). Densities of the very abundant rotifer Polyarthra were >300% greater in fish enclosures than controls by Day 12, and the rotifers Synchaeta and predaceous Ploesoma were significantly more abundant in the presence of perch. Increases in rotifers and cladocera suggest indirect, positive effects of fish related to significantly higher phytoplankton biomass or decreased densities of predaceous copepods. Densities of eight of ten zooplankton groups examined declined significantly when mussels were present, and calanoid copepodids also declined but not significantly. Chlorophyll‐ a concentrations were slightly lower in mussel ... Article in Journal/Newspaper Copepods Rotifer Wiley Online Library Lawrence River ENVELOPE(-115.002,-115.002,58.384,58.384) River Research and Applications 19 3 265 279 |
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Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Abstract Physical conditions are usually considered pre‐eminent in controlling river plankton, but biotic interactions may be important in slackwater areas. To begin testing this general hypothesis, we conducted a 12‐day, predator–prey experiment in 3500 litre mesh enclosures in a slackwater area of the St. Lawrence River using planktivorous, juvenile yellow perch ( Perca flavescens ) and Dreissena mussels. Results generally supported our hypotheses that: (1) perch would directly suppress large zooplankton via predation but benefit microzooplankton through indirect interactions; and (2) dreissenids would directly depress rotifer densities via predation and have indirect negative effects on macrozooplankton. Based on gut contents of experimental fish, cladocera were the principal prey of smaller yellow perch ( c . 46–50 mm), followed by copepods, ostracods, and rotifers. Larger juvenile perch ( c . 67–73 mm) fed almost exclusively on copepods and ostracods. Densities of calanoid copepodids, nauplii, and some cyclopoid copepods ( Diacyclops thomasi ) were significantly depressed by perch, and adult Eurytemora affinis (99% of adult calanoids) essentially disappeared from fish enclosures. Despite being a favourite prey item of small perch, densities of the small cladoceran Bosmina ( Sinobosmina ) spp. were significantly higher when fish were present (150% greater than control densities on Day 12). Densities of the very abundant rotifer Polyarthra were >300% greater in fish enclosures than controls by Day 12, and the rotifers Synchaeta and predaceous Ploesoma were significantly more abundant in the presence of perch. Increases in rotifers and cladocera suggest indirect, positive effects of fish related to significantly higher phytoplankton biomass or decreased densities of predaceous copepods. Densities of eight of ten zooplankton groups examined declined significantly when mussels were present, and calanoid copepodids also declined but not significantly. Chlorophyll‐ a concentrations were slightly lower in mussel ... |
format |
Article in Journal/Newspaper |
author |
Thorp, James H. Casper, Andrew F. |
spellingShingle |
Thorp, James H. Casper, Andrew F. Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River |
author_facet |
Thorp, James H. Casper, Andrew F. |
author_sort |
Thorp, James H. |
title |
Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River |
title_short |
Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River |
title_full |
Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River |
title_fullStr |
Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River |
title_full_unstemmed |
Importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the St. Lawrence River |
title_sort |
importance of biotic interactions in large rivers: an experiment with planktivorous fish, dreissenid mussels and zooplankton in the st. lawrence river |
publisher |
Wiley |
publishDate |
2003 |
url |
http://dx.doi.org/10.1002/rra.703 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Frra.703 https://onlinelibrary.wiley.com/doi/pdf/10.1002/rra.703 |
long_lat |
ENVELOPE(-115.002,-115.002,58.384,58.384) |
geographic |
Lawrence River |
geographic_facet |
Lawrence River |
genre |
Copepods Rotifer |
genre_facet |
Copepods Rotifer |
op_source |
River Research and Applications volume 19, issue 3, page 265-279 ISSN 1535-1459 1535-1467 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/rra.703 |
container_title |
River Research and Applications |
container_volume |
19 |
container_issue |
3 |
container_start_page |
265 |
op_container_end_page |
279 |
_version_ |
1811646391560175616 |