Journal of the Marine Biological Association of the United Kingdom

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Journal of the Marine Biological Association of the United Kingdom (2010), 90:1153-1159 Cambridge University Press
Copyright © Marine Biological Association of the United Kingdom 2009
doi:10.1017/S0025315409990488

Research Article

Climatic and oceanic influences on the abundance of gelatinous zooplankton in the North Sea


C.P. Lynama1 p1 c1, M.J. Attrilla2 and M.D. Skogena3a4

a1 Marine Institute, Rinville, Oranmore, County Galway, Republic of Ireland
a2 Marine Biology & Ecology Research Centre, Marine Institute, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK
a3 Institute of Marine Research, PO Box 1870, Nordnes, N-5817 Bergen, Norway
a4 Bjerknes Centre for Climate Research, Allegaten 55, N-5007 Bergen, Norway
Article author query
lynam cp [PubMed]  [Google Scholar]
attrill mj [PubMed]  [Google Scholar]
skogen md [PubMed]  [Google Scholar]

Abstract

Oceanographically based mechanisms are shown to explain the spatial variation in the climatic relationship between the abundance of medusae (Aurelia aurita and Cyanea spp. of the class Scyphozoa), in the North Sea between 1971 and 1986 during June–August, and the winter (December–March) North Atlantic Oscillation Index (NAOI). A scyphomedusa population to the west of Denmark shows a strong inverse relationship between medusa abundance and fluctuations in the NAOI; the NAOI correlates strongly (P < 0.001) with both annual sea surface temperature (SST) at 6.5°E 56.5°N (1950–2008) and with winter precipitation on the Danish coast at Nordby (1900–2008) suggesting a direct link between the influence of climate and medusae abundance. In contrast, scyphomedusa abundance and distribution in the northern North Sea appears to be influenced by oceanic and mixed water inflow, which may overwhelm or mask any direct climatic influence on jellyfish abundance. Similarly, advection can also explain much of the interannual variability (1959–2000) in the abundance of other gelatinous zooplankton taxa (Cnidaria, Ctenophora and Siphonophora) in the northern North Sea as identified by the capture of gelatinous tissue and nematocysts (stinging cells) in Continuous Plankton Recorder samples. Jellyfish (Scyphozoa) in the southern North Sea may benefit from low temperature anomalies and the long-term effects of global warming might suppress Aurelia aurita and Cyanea spp. populations there. However, the biological response to temperature is complex and future research is required in this area.

(Received September 16 2008)

(Accepted May 06 2009)

(Online publication July 13 2009)

Keywordsjellyfish; climate; North Sea; inflow; temperature; North Atlantic Oscillation Index

Correspondence:

c1 Correspondence should be addressed to: C.P. Lynam, CEFAS, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK email: Chris.Lynam@cefas.co.uk

p1 Present address: CEFAS, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK