Fins On!

The Mediterranean Sea holds many living wonders, some yet undiscovered, others well-studied. Being a semi-enclosed basin with warm weather conditions, the evaporation prevails over the rain and river inflow, placing it among the most complex marine ecosystems of the world. Interestingly, there is a small part, the Adriatic Sea, that holds almost half of the recorded marine species found in the Mediterranean Sea, and is considered rich in endemic marine flora and fauna. However, the ship traffic, overfishing, severe trawling, aquaculture, eutrophication and the rising of temperatures (tropicalization) make this place extremely exploited and at risk of biodiversity loss.

Photo Credits: Blue shark captured by Tony Meyer, common thresher shark, shortfin mako captured by Miguel Angel Eliceche Constantini

Amidst these factors, the most threatened species are those that have a large body size,  long life cycles and low reproduction rates, and they are referred as K-strategists, as opposed to r-strategists, that are smaller in body size, with short life expectancy and higher production of offspring. So, if we imagine for instance the anchovy fisheries, that are r-strategists, the bigger species that usually get caught in the fishing nets, such as sharks and rays, are victims of bycatch, and depending on the commercial value of these species, their corpses are either sold on the fish market or thrown back at sea injured or even dead. Moreover, blue sharks (Prionace glauca), common thresher sharks (Alopias vulpinus) and shortfin makos (Isurus oxyrinchus), for example, are the most common bycatch of tuna and swordfish fisheries that utilize pelagic longlines.

Longlining and sharks. Photo Credit: Stop Finning

Unfortunately, pelagic shark species are not the only ones at risk. The Adriatic Sea was once regularly populated by the common angelshark (Squatina squatina), a species that lives in proximity to the sea bottom, thus called demersal. Between 1867 and 1918, under the Austro-Hungarian Empire, S. squatina supported the local fishing fleet. Years later, the scientific assessments of the species showed a drastic decline in their presence, with an almost complete absence in the North Adriatic Sea. Nowadays, the species is considered as “Critically endangered” by the IUCN Red List of Threatened Species due to the bycatch from fisheries of demersal species, using trawls, that also cause tremendous disturbance of the sea bottom.

Angelshark Squatina squatina

Oftentimes, the humans’ perception of sharks is misunderstood as we connect them to danger and mysteriousity. Great white sharks (Carcharodon carcharias) in the North Adriatic Sea, for example, were persecuted by fishers that were paid by the Austro-Hungarian government because they were seen as a nuisance for the local fisheries. Even later on, the movie industry has presented sharks as dreadful and bloodthirsty, deluding the general public. Despite the misconceptions, though, the rising of awareness through various social media channels has proven to be effective in informing the general public.

Great White Shark Carcharodon carcharias. Photo Credit: Euan Rannachan

At present, the collective awareness can help establish fishing closures in parts where the shark populations are depleted, and thus, restore the ecosystem equilibrium.

One similar initiative has been recently proposed by the European Union citizens, in supporting the extension of the REGULATION (EU) No 605/2013 that would prohibit the trade of shark and ray fins in the European Union (more information on Stop Finning). So if you would like to contribute in supporting this initiative, you can go to the page and fill in the given form! The initiative can be signed by any citizen of the European Union, it takes a couple of minutes to sign and requires you to leave your ID number. If we can reach 1 million signatures within this year, we might help in the conservation of sharks.

Are you with us?

Barausse, A., Correale, V., Curkovic, A., Finotto, L., Riginella, E., Visentin, E. and Mazzoldi, C., 2014. The role of fisheries and the environment in driving the decline of elasmobranchs in the northern Adriatic Sea. ICES Journal of Marine Science, 71(7), pp.1593-1603.

Bargnesi, F., Lucrezi, S. and Ferretti, F., 2020. Opportunities from citizen science for shark conservation, with a focus on the Mediterranean Sea. The European Zoological Journal, 87(1), pp.20-34.

Bonanomi, S., Pulcinella, J., Fortuna, C.M., Moro, F. and Sala, A., 2018. Elasmobranch bycatch in the Italian Adriatic pelagic trawl fishery. PloS one, 13(1), p.e0191647.

Campana, S.E., Ferretti, F. and Rosenberg, A., 2016. Sharks and other elasmobranchs. The first global integrated marine assessment, World Ocean Assessment I, United Nations, pp.1437-1451.

Coll, M., Piroddi, C., Steenbeek, J., Kaschner, K., Lasram, F.B.R., Aguzzi, J., Ballesteros, E., Bianchi, C.N., Corbera, J., Dailianis, T. and Danovaro, R., 2010. The biodiversity of the Mediterranean Sea: estimates, patterns, and threats. PloS one, 5(8), p.e11842.

Fowler, S., 2016. Review and gap analysis of shark and ray bycatch mitigation measures employed by fisheries management bodies. Memorandum of Understanding on the Conservation of Migratory Sharks. Web link.Holcer, D. and Lazar, B., 2017. New data on the occurrence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea. Natura Croatica: Periodicum Musei Historiae Naturalis Croatici, 26(2), pp.313-320.

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