Variability in the structure of pelagic fish communities: A pitfall for management of herring in the Baltic Sea?

Abstract

The Baltic herring (Clupea harengus membras L.) is traditionally one of the main targets of pelagic fisheries in the Baltic Sea, taken mostly in mixed fishery with sprat. The annual total landings amounted around 258 000 t on average for the most recent 20 years. The international management of the Baltic herring stocks rely on the Total Allowable Catch (TAC) agreements and on a few technical measures (gear restrictions in certain areas, closed areas and periods for fishery) as the operational management tools. There are three major agreed management units of herring in the Baltic: Central Baltic herring, Herring in the Gulf of Bothnia and Gulf of Riga herring. Despite of decades–long efforts in applying of regulatory measures, the fate of the stocks has been different: The Central Baltic herring has shown two major declines during its management history while the two other stocks have shown broadly opposite trends. The paper is discussing the possible reasons for the different outcome of management like compliance of fishery with the scientific advice and changes on pelagic communities of the Baltic, focusing on the dynamics in mean weight of herring as another factor potentially effecting on management success across the area.