Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract Full Text

Rapana venosa - new exploitable resource at the Romanian Black Sea coast.

Abstract

Starting with 2009, Romanian Black Sea fishery catches have recorded an increasing trend. Yet, this is not the consequence of a massive restoration of fish stocks or an increase of fishing effort, but the result of shifting the target species. The invasive gastropod Rapana venosa (Valenciennes, 1846) has raised the interest of economic operators due to its low exploitation costs compared to other valuable species (turbot, for instance). At the Romanian coast, fishing for R. venosa was first performed only using divers, because this is a method which provides high selectivity of the catches and protection of habitats. Starting with 2013, beam trawls were legalized and started to be used (Order no. 1696 of 11.07.2013, Order no. 400 of 2013). After the legalization of the beam trawl, the catch increased 2.27 times compared to 2012 (from 588 t in 2012 to 1,338 tonnes in 2013), the TAC being carried out at a rate of 23.5%. Many commercial companies in the field have shifted their business towards purchasing or manufacturing this type of gear, corresponding to their vessel capacity. From the selectivity point of view, the gear used for rapa whelk fishing (beam trawl) does not retain immature specimens of R. venosa and no juvenile fish belonging to certain demersal fish species (gobies, red mullet, whiting). Yet, there is some concern on the potential effects of beam trawl on the seabed, which should be investigated in the future. Also, as a consequence of exploitation, the drop of R. venosa populations was acknowledged, which requires future research meant to determine the actual stock size and total allowable catch (TAC), aiming at underpinning the rapa whelk fisheries on a scientific background and to reconcile these economically valuable activities for coastal communities with nature conservation.