From fish to jellyfish in the eutrophicated Limfjorden (Denmark)

Publication: Research - peer-reviewJournal article – Annual report year: 2012

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From fish to jellyfish in the eutrophicated Limfjorden (Denmark). / Riisgård, Hans Ulrik; Andersen, Per; Hoffmann, Erik.

In: Estuaries and Coasts, Vol. 35, No. 3, 2012, p. 701-713.

Publication: Research - peer-reviewJournal article – Annual report year: 2012

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Riisgård, Hans Ulrik; Andersen, Per; Hoffmann, Erik / From fish to jellyfish in the eutrophicated Limfjorden (Denmark).

In: Estuaries and Coasts, Vol. 35, No. 3, 2012, p. 701-713.

Publication: Research - peer-reviewJournal article – Annual report year: 2012

Bibtex

@article{9afaa5cd25e6486cb14e57d0082ca956,
title = "From fish to jellyfish in the eutrophicated Limfjorden (Denmark)",
abstract = "The heavily eutrophicated Limfjorden (Denmark) provides a good illustration of the value of long-term monitoring, especially if this is combined with an experimental, interdisciplinary research approach. Here, we first give a short overview of the environmental status of Limfjorden, including the historical development of nutrient overloading and subsequent oxygen depletion in near-bottom water, and how the annual landings of edible bottom-dwelling fish species (plaice, flounder, eel and others) caught in Limfjorden have decreased from about 2,500 t in the early 1920s to only about 20 t in recent years where the fish have been replaced by an increasing number of especially the moon jellyfish, Aurelia aurita, which mainly preys on zooplankton. Next, we evaluate the ecological consequences of the present high number of jellyfish, based on data from recent years’ research on the abundance of jellyfish, their population dynamics and predation impact. In Limfjorden, the benthic polyp stage of A. aurita ensures a large number of small ephyrae in the early spring and subsequently a large population of adult medusae that control the zooplankton during summer and autumn. The holopelagic invasive ctenophore Mnemiopsis leidyi, which was observed in Limfjorden for the first time in 2007, is a second carnivore adding additional predation pressure of the indigenous A. aurita so that copepods and other mesozooplankton organisms may be virtually absent, as observed in 2008 and 2009 where ciliates made up a substantial part of the zooplankton biomass. Marine environmental management programmes should be aware of the increasing importance of both indigenous and new invasive jellyfish species that may show mass occurrence in especially eutrophicated and overfished areas",
author = "Riisgård, {Hans Ulrik} and Per Andersen and Erik Hoffmann",
year = "2012",
doi = "10.1007/s12237-012-9480-4",
volume = "35",
pages = "701--713",
journal = "Estuaries and Coasts",
issn = "1559-2723",
publisher = "Springer New York LLC",
number = "3",

}

RIS

TY - JOUR

T1 - From fish to jellyfish in the eutrophicated Limfjorden (Denmark)

AU - Riisgård,Hans Ulrik

AU - Andersen,Per

AU - Hoffmann,Erik

PY - 2012

Y1 - 2012

N2 - The heavily eutrophicated Limfjorden (Denmark) provides a good illustration of the value of long-term monitoring, especially if this is combined with an experimental, interdisciplinary research approach. Here, we first give a short overview of the environmental status of Limfjorden, including the historical development of nutrient overloading and subsequent oxygen depletion in near-bottom water, and how the annual landings of edible bottom-dwelling fish species (plaice, flounder, eel and others) caught in Limfjorden have decreased from about 2,500 t in the early 1920s to only about 20 t in recent years where the fish have been replaced by an increasing number of especially the moon jellyfish, Aurelia aurita, which mainly preys on zooplankton. Next, we evaluate the ecological consequences of the present high number of jellyfish, based on data from recent years’ research on the abundance of jellyfish, their population dynamics and predation impact. In Limfjorden, the benthic polyp stage of A. aurita ensures a large number of small ephyrae in the early spring and subsequently a large population of adult medusae that control the zooplankton during summer and autumn. The holopelagic invasive ctenophore Mnemiopsis leidyi, which was observed in Limfjorden for the first time in 2007, is a second carnivore adding additional predation pressure of the indigenous A. aurita so that copepods and other mesozooplankton organisms may be virtually absent, as observed in 2008 and 2009 where ciliates made up a substantial part of the zooplankton biomass. Marine environmental management programmes should be aware of the increasing importance of both indigenous and new invasive jellyfish species that may show mass occurrence in especially eutrophicated and overfished areas

AB - The heavily eutrophicated Limfjorden (Denmark) provides a good illustration of the value of long-term monitoring, especially if this is combined with an experimental, interdisciplinary research approach. Here, we first give a short overview of the environmental status of Limfjorden, including the historical development of nutrient overloading and subsequent oxygen depletion in near-bottom water, and how the annual landings of edible bottom-dwelling fish species (plaice, flounder, eel and others) caught in Limfjorden have decreased from about 2,500 t in the early 1920s to only about 20 t in recent years where the fish have been replaced by an increasing number of especially the moon jellyfish, Aurelia aurita, which mainly preys on zooplankton. Next, we evaluate the ecological consequences of the present high number of jellyfish, based on data from recent years’ research on the abundance of jellyfish, their population dynamics and predation impact. In Limfjorden, the benthic polyp stage of A. aurita ensures a large number of small ephyrae in the early spring and subsequently a large population of adult medusae that control the zooplankton during summer and autumn. The holopelagic invasive ctenophore Mnemiopsis leidyi, which was observed in Limfjorden for the first time in 2007, is a second carnivore adding additional predation pressure of the indigenous A. aurita so that copepods and other mesozooplankton organisms may be virtually absent, as observed in 2008 and 2009 where ciliates made up a substantial part of the zooplankton biomass. Marine environmental management programmes should be aware of the increasing importance of both indigenous and new invasive jellyfish species that may show mass occurrence in especially eutrophicated and overfished areas

U2 - 10.1007/s12237-012-9480-4

DO - 10.1007/s12237-012-9480-4

M3 - Journal article

VL - 35

SP - 701

EP - 713

JO - Estuaries and Coasts

T2 - Estuaries and Coasts

JF - Estuaries and Coasts

SN - 1559-2723

IS - 3

ER -