Salinity dependence of recruitment success of the sea star Asterias rubens in the brackish western Baltic Sea.

Casties, Isabel, Clemmesen, Catriona , Melzner, Frank and Thomsen, Jörn (2015) Salinity dependence of recruitment success of the sea star Asterias rubens in the brackish western Baltic Sea. Open Access Helgoland Marine Research, 69 (2). pp. 169-175. DOI 10.1007/s10152-015-0425-8.

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Abstract

Salinity strongly influences development and distribution of the sea star Asterias rubens. In Kiel Fjord, located in the western Baltic Sea, A. rubens is the only echinoderm species and one of the main benthic predators controlling blue mussel (Mytilus edulis) abundance. However, Kiel Fjord with an average salinity of about 15 is located close to the eastern distribution boundary of A. rubens in the Baltic Sea. In this study, we combined field and laboratory investigations to test whether the salinity of Kiel Fjord is high enough to enable successful development of A. rubens. Sea star eggs were fertilized in vitro, and development was monitored in the laboratory at four salinities (9, 12, 15 and 18) for 10 weeks. At a salinity of 9, development ceased prior to the blastula stage. At a salinity of 12, no larvae reached metamorphosis. At higher salinities, larvae developed normally and metamorphosed into juvenile sea stars. Abundances of A. rubens larvae and settled juveniles were also observed in Kiel Fjord and correlated to salinity values measured from March until June during 6 years (2005–2010). Results revealed high A. rubens settlement rates only in 2009, the year when salinity was the highest and least variable during the period of spawning and larval development. It appears that only years with high and stable salinities permit recruitment of A. rubens in Kiel Fjord. Projected desalination of the Baltic Sea could shift the distribution of A. rubens in the western Baltic Sea north-westwards and may lead to local extinction of a keystone species of the benthic ecosystem.

Document Type: Article
Additional Information: WOS:000354241700004
Keywords: Asterias rubens; Salinity tolerance; Early development; Baltic Sea
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-N Experimental Ecology - Food Webs
OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EV Marine Evolutionary Ecology
OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Refereed: Yes
Open Access Journal?: Yes
Publisher: Springer
Date Deposited: 09 Feb 2015 09:28
Last Modified: 28 May 2018 10:04
URI: https://oceanrep.geomar.de/id/eprint/27346

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