Stanisław Robak, Tomasz Nermer
ABSTRACT. The individual abundance of populations of European eel, Anguilla anguilla (L.), inhabiting the Vistula Lagoon is determined primarily by intense, systematic stocking. Stocking conducted annually in the 1970-1994 period with glass eel in average quantities of 4,670,000 individuals resulted in catches of a maximum of 400 tons annually (1980). Stocking was discontinued (1995-2004) and then commenced again in 2005-2008, when 65,000 reared fry (10 g /individual) were released in to the lagoon, but this resulted in reduced eel catches of barely 3.7 tons in 2011. Conservation through the Polish Eel Management Plan (PEMP) presents an opportunity to restore the role of this species in the ichthyofauna of the Vistula Lagoon. Stocking that was performed in 2011-2015 resulted in dramatic improvement in the status of the population while increasing catches to 27.4 tons in 2016. Age determinations of the eel caught confirmed that a high percentage of them originated from stocking. The age structure of the fish caught was dominated by fish aged 3+ and 5+ that had exceeded the minimum landing size of 50 cm. Considering the size of the fry released during stocking, presumably the eels in the Vistula Lagoon were caught after they reach the age of 6+ counting the years spent in natural conditions starting from glass fry. The measures implemented as part of the PEMP since 2010 have influenced positively the condition of the eel population in the Vistula Lagoon and have significantly improved the fisheries management status of the region.
Keywords: Vistula Lagoon, Eel, stocking, catch, conservation, Eel Management Plan
Przyjęto po recenzji 11.12.2017 r.