Abstract

The development of three pikeperch (Sander lucioperca (L.)) populations in the northern Baltic Sea was monitored using standardized multimesh gillnets in 1995-2009. Declining trends in the abundances of pikeperch over 40 cm total length, low numbers of individuals older than 6 years, and high mortality rates were observed in all three populations. In the site with the largest commercial catches per unit area and a rapidly increased colony of great cormorants (Phalacrocorax carbo sinensis Blumenbach 1798), also the abundance of pikeperch below 40 cm total length and year-class strength showed declining trends. The adverse population level changes did not correlate with changes in water quality or eutrophication status. Together, the results suggest that in all study sites fisheries are harvesting a large proportion of the pikeperch soon after or even before reaching the maturity, and that predation from great cormorants may increase mortality of juveniles. Pikeperch is important not only for fisheries but also for ecosystem functioning, and our results point at the need for further management measures to ensure viable populations in the areas studied.

Keywords

Year-class strength; Commercial fishing; Multimesh gillnet monitoring; Mortality; Great cormorant

Published in

AMBIO: A Journal of the Human Environment
2014, Volume: 43, number: 3, pages: 325-336
Publisher: SPRINGER

SLU Authors

• Bergström, Ulf

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    
Associated SLU-program

Coastal and sea areas


Sustainable Development Goals

Conserve and sustainably use the oceans, seas and marine resources for sustainable development


UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1007/s13280-013-0429-z

Permanent link to this page (URI)

https://res.slu.se/id/publ/53519