Several species of large predatory sharks in the Mediterranean Sea have decreased from 96-99.99% relative to their former abundances, according to a new scientific study called “Loss of Large Predatory Sharks from the Mediterranean Sea”, released in the journal Conservation Biology. The study, which assessed records dating back to the early 19th century, explains that these species, hammerheads (Sphyrna spp.), blue (Prionace glauca), shortfin mako (Isurus oxyrinchus), porbeagle (Lamna nasus) and thresher sharks (Alopias vulpinus), would all be considered Critically Endangered according to World Conservation Union (IUCN) criteria. Nevertheless, none of the catches of these species are managed in Mediterranean waters.
As a sea with a long history of fishing, including shark fishing, the Mediterranean has now regrettably been named one of the most dangerous places in the world for sharks, according to the IUCN. Over 40% of sharks and related ray species there are threatened with extinction. The main culprit is overfishing, as sharks and rays are affected by both high targeted and accidental catches. Habitat degradation and other anthropogenic effects in coastal areas has been another reason for this decline.
For many years, a lack of population data has impeded shark conservation in the Mediterranean, but Oceana, the international marine conservation organisation, highlights the importance of this study in filling these information gaps and urges the European Union and Member states to stop delaying shark conservation. The situation of Mediterranean sharks can be improved through national and regional measures, including the establishment of fisheries restrictions and protection through environmental conventions, and via regional fishery management bodies that regulate international waters. The European Commission is currently developing a European Plan of Action for Sharks, which should also lead to greater and stronger EU shark management in the Mediterranean.
“For a long time sharks were not considered valuable species. But today many nations are targeting these species and taking advantage of the fact that their catches are not managed. Shark fisheries have slipped under the radar, but now the EU has more reason, and more chances, than ever to help improve the future of Mediterranean sharks.” said Rebecca Greenberg, marine scientist with Oceana.
As already seen in some parts of the world, the disappearance of top predator sharks could result in cascading negative effects in the greater marine ecosystem, including a disruption in the food web and the disappearance of other commercial species. The possible effects of top predator loss in the Mediterranean are unpredictable, but they will be inevitable if current levels of fishing pressure continue. “The time to act is now,” concludes Greenberg.