Sammanfattning

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.

Nyckelord

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

Publicerad i

AMBIO: A Journal of the Human Environment
2014, Volym: 43, nummer: 3, sidor: 325-336
Utgivare: SPRINGER

SLU författare

• Bergström, Ulf

  • Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
    
Associerade SLU-program

Kust och hav


Globala målen

SDG14 Bevara och nyttja haven och de marina resurserna på ett hållbart sätt för en hållbar utveckling


UKÄ forskningsämne

Ekologi


Publikationens identifierare

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

Permanent länk till denna sida (URI)

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