A fish introduction and its impact on the plankton community
This thesis is about how one species can invade an ecosystem and change the whole biological community within a few years. The question is whether such changes can be foreseen or are more or less unpredictable? Biological communities in lakes are vulnerable to fish predation and the zooplankton is s...
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The University of Bergen
2012
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ftunivbergen:oai:bora.uib.no:1956/6395 2023-05-15T13:28:10+02:00 A fish introduction and its impact on the plankton community Regmi, Bishnu Prasad 2012-08-20 application/pdf http://hdl.handle.net/1956/6395 eng eng The University of Bergen Paper I: Regmi, B. P. & P. Larsson. Development and diet of Eurasian perch (Perca fluviatilis) when invading a lake without planktivorous fish (manuscript). Full text not available in BORA. Paper II: Regmi, B. P., J. S. Wivegh, F. Knudsen & P. Larsson. Vertical distribution and diel migration of phantom midge (Chaoborus flavicans) larvae before and after invasion of Eurasian perch (Perca fluviatilis) (submitted). Full text not available in BORA. Paper III: Regmi, B. P., J. S. Wivegh & A. Hobæk. Population decline and life-cycle adjustment in a phantom midge (Chaoborus flavicans) population after introduction of planktivorous fish (manuscript). Full text not available in BORA. Paper IV: Regmi, B. P., I. Wathne, J. Giske, A. Hobæk & P. Larsson. From phantom midges (Chaoborus flavicans) to perch (Perca fluviatilis): zooplankton community changes (manuscript). Full text not available in BORA. urn:isbn:978-82-308-2090-2 (print version) http://hdl.handle.net/1956/6395 Copyright the author. All rights reserved Doctoral thesis 2012 ftunivbergen 2023-03-14T17:44:03Z This thesis is about how one species can invade an ecosystem and change the whole biological community within a few years. The question is whether such changes can be foreseen or are more or less unpredictable? Biological communities in lakes are vulnerable to fish predation and the zooplankton is strongly affected by the fish types present. Of particular importance is whether they feed on zooplankton (planktivore), benthic animals (benthivore) or are fish eaters (piscivore). Lake Myravatn in Bergen had for a long time a very rare fish community consisting of only piscivore fish due to the introduction of Northern pike (Esox lucius) about 200 years ago. No other fish survived there except some eel (Anguilla anguilla). The consequence of this was a zooplankton community with large species that are usually eliminated by planktivorous fish. Predation on the zooplankton was caused by an invertebrate, larvae of the phantom midge (Chaoborus flavicans), feeding on small zooplankton individuals. This situation was completely changed when Eurasian perch (Perca fluviatilis) was illegally introduced by unknown person(s) and for unknown reasons, most likely in autumn 2006. Since studies on the zooplankton were ongoing, the consequences for the zooplankton could be recorded. The monitoring of the lake included both quantitative and qualitative zooplankton sampling and fishing with multi-mesh gill nets and echo-sounding able to discriminate between fish and larvae of phantom midge. Contemporary theory predicted that the perch would encounter very good conditions in the lake with a superabundance of invertebrate prey of optimal size. Both growth and reproduction would be exceptional and a dense perch population would quickly establish. This would reduce the large zooplankton species in the lake, i.e. Daphnia pulex, D. longispina and the phantom midge larvae. Disappearance of the invertebrate predator, the phantom midge, and the competitors, the daphnids, would give an opportunity for smaller species to flourish. The large ... Doctoral or Postdoctoral Thesis Anguilla anguilla University of Bergen: Bergen Open Research Archive (BORA-UiB) Bergen |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
This thesis is about how one species can invade an ecosystem and change the whole biological community within a few years. The question is whether such changes can be foreseen or are more or less unpredictable? Biological communities in lakes are vulnerable to fish predation and the zooplankton is strongly affected by the fish types present. Of particular importance is whether they feed on zooplankton (planktivore), benthic animals (benthivore) or are fish eaters (piscivore). Lake Myravatn in Bergen had for a long time a very rare fish community consisting of only piscivore fish due to the introduction of Northern pike (Esox lucius) about 200 years ago. No other fish survived there except some eel (Anguilla anguilla). The consequence of this was a zooplankton community with large species that are usually eliminated by planktivorous fish. Predation on the zooplankton was caused by an invertebrate, larvae of the phantom midge (Chaoborus flavicans), feeding on small zooplankton individuals. This situation was completely changed when Eurasian perch (Perca fluviatilis) was illegally introduced by unknown person(s) and for unknown reasons, most likely in autumn 2006. Since studies on the zooplankton were ongoing, the consequences for the zooplankton could be recorded. The monitoring of the lake included both quantitative and qualitative zooplankton sampling and fishing with multi-mesh gill nets and echo-sounding able to discriminate between fish and larvae of phantom midge. Contemporary theory predicted that the perch would encounter very good conditions in the lake with a superabundance of invertebrate prey of optimal size. Both growth and reproduction would be exceptional and a dense perch population would quickly establish. This would reduce the large zooplankton species in the lake, i.e. Daphnia pulex, D. longispina and the phantom midge larvae. Disappearance of the invertebrate predator, the phantom midge, and the competitors, the daphnids, would give an opportunity for smaller species to flourish. The large ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Regmi, Bishnu Prasad |
spellingShingle |
Regmi, Bishnu Prasad A fish introduction and its impact on the plankton community |
author_facet |
Regmi, Bishnu Prasad |
author_sort |
Regmi, Bishnu Prasad |
title |
A fish introduction and its impact on the plankton community |
title_short |
A fish introduction and its impact on the plankton community |
title_full |
A fish introduction and its impact on the plankton community |
title_fullStr |
A fish introduction and its impact on the plankton community |
title_full_unstemmed |
A fish introduction and its impact on the plankton community |
title_sort |
fish introduction and its impact on the plankton community |
publisher |
The University of Bergen |
publishDate |
2012 |
url |
http://hdl.handle.net/1956/6395 |
geographic |
Bergen |
geographic_facet |
Bergen |
genre |
Anguilla anguilla |
genre_facet |
Anguilla anguilla |
op_relation |
Paper I: Regmi, B. P. & P. Larsson. Development and diet of Eurasian perch (Perca fluviatilis) when invading a lake without planktivorous fish (manuscript). Full text not available in BORA. Paper II: Regmi, B. P., J. S. Wivegh, F. Knudsen & P. Larsson. Vertical distribution and diel migration of phantom midge (Chaoborus flavicans) larvae before and after invasion of Eurasian perch (Perca fluviatilis) (submitted). Full text not available in BORA. Paper III: Regmi, B. P., J. S. Wivegh & A. Hobæk. Population decline and life-cycle adjustment in a phantom midge (Chaoborus flavicans) population after introduction of planktivorous fish (manuscript). Full text not available in BORA. Paper IV: Regmi, B. P., I. Wathne, J. Giske, A. Hobæk & P. Larsson. From phantom midges (Chaoborus flavicans) to perch (Perca fluviatilis): zooplankton community changes (manuscript). Full text not available in BORA. urn:isbn:978-82-308-2090-2 (print version) http://hdl.handle.net/1956/6395 |
op_rights |
Copyright the author. All rights reserved |
_version_ |
1766402615117086720 |