alexa Abstract | Jellyfish and Ctenophores in the Environmentally Degraded Limfjorden (Denmark) During 2014 - Species Composition, Population Densities and Predation Impact
ISSN: 2150-3508

Fisheries and Aquaculture Journal
Open Access

OMICS International organises 3000+ Global Conferenceseries Events every year across USA, Europe & Asia with support from 1000 more scientific Societies and Publishes 700+ Open Access Journals which contains over 50000 eminent personalities, reputed scientists as editorial board members.

Open Access Journals gaining more Readers and Citations

700 Journals and 15,000,000 Readers Each Journal is getting 25,000+ Readers

This Readership is 10 times more when compared to other Subscription Journals (Source: Google Analytics)

Research Article Open Access


Species composition, population densities and size of jellyfish and ctenophores were recorded during 5 cruises in the heavily eutrophicated Limfjorden in 2014. No or very few ctenophores (Pleurobrachia pileus) and jellyfish (Aurelia aurita, Cyanea lamarckii) were recorded in April and June 2014, whereas in August and September numerous small individuals of the invasive ctenophore Mnemiopsis leidyi were found on all 4 locations studied, which were strongly reduced in population density during November. M. leidyi exerted a notable predation impact, most pronounced in Løgstør Bredning and Skive Fjord in August when the estimated half-lives of zooplankton were 4.8 and 7.3 d, respectively, and in late September, when the half-life in Skive Fjord was only 2.2 d. Severe oxygen depletion in Løgstør Bredning and Skive Fjord between June and September resulted in a release of nutrients. This was followed by a bloom of the dinoflagellate Noctiluca scintillans and a subsequent peak in the abundance of copepods which decreased rapidly after the introduction of M. leidyi into Limfjorden from the North Sea (between early April and mid- July) to become virtually absent during the rest of the season. This subsequently resulted in starvation and decay of the M. leidyi population. The small predatory ctenophore Beroe gracilis was recorded on most locations during August and September 2014 but although B. gracilis eats small M. leidyi, their low number suggested a negligible predation impact on the M. leidyi population. Our present understanding of the many biological and environmental factors that control the species composition, abundance and predation impact of jellyfish and ctenophore populations in Limfjorden are discussed. It is concluded that there are many unsolved questions, e.g. how gelatinous predation of zooplankton may reinforce anoxia and further habitat degradation in eutrophicated waters.

To read the full article Peer-reviewed Article PDF image | Peer-reviewed Full Article image

Author(s): Hans Ulrik Riisgård, Josephine Goldstein, Kim Lundgreen and Florian Lüskow


Mnemiopsis leidyi, Beroe gracilis, Pleurobrachia pileus, Aurelia aurita, Predation impact, Hydrography, Zooplankton, Limfjorden, Oxygen depletion, Hypoxia, Sustainable Aquaculture, Benefits of Aquaculture, Best Aquaculture Practices.

Share This Page

Additional Info

Loading Please wait..
Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version