An Oceana and Marviva report proves the need to protect bluefin tuna spawning areas in the Mediterranean
The study provides new data about the reproductive habits of this and other overexploited species, such as swordfish
Press Release Date: May 6, 2010
Oceana and Marviva presented a report today in Palma de Mallorca with preliminary results of the larval samplings taken in 2008 on board the Marviva Med oceanographic research vessel. The study was undertaken to obtain new data about Mediterranean spawning areas of bluefin tuna, and other large pelagic species such as swordfish, and to propose the creation of marine protected areas.
The report is the first of its kind compiled by a conservation organisation and provides new data about bluefin tuna, a threatened species which is on the verge of collapse due to overfishing. The following is included in the report:
- Information about bluefin tuna spawning areas in the south Tyrrhenian, Malta Channel and in the Aegean Sea, late in the season compared to their reproductive peaks.
- New data about the reproduction of other tuna species such as skipjack (Katsuwonus pelamis), and additional data about the spawning areas of another overexploited species, swordfish, which will be used to propose marine protected areas.
Ricardo Aguilar, director of research and projects at Oceana Europe, highlighted the need to continue with this type of research in the future, not only concerning bluefin tuna, but also other commercial species like swordfish: “There is a lack of data concerning bluefin tuna spawning areas in the Mediterranean and practically no data at all concerning other species like skipjack tuna. However, protecting these areas is essential for their conservation. Regarding bluefin tuna, the countries that make up the International Commission for the Conservation of Atlantic Tunas (ICCAT) have made a commitment to facilitate data for 2010 to designate new marine reserves for this species. However, it may already be too late for tuna.”
The samples showed large concentrations of an invasive species from the West Atlantic, the ctenophore Mnemiopsis leidyi, introduced in the Black Sea during the 80s through vessels’ ballast waters and currently in expansion throughout Mediterranean waters. This species is potentially dangerous for a large number of commercial species such as the anchovy because it feeds off its eggs and may irreparably damage some fisheries.
Furthermore, larvae from other commercial species were also identified, including mackerel (Trachurus trachurus) and anchovy (Engraulis encrasicolus), and from rare and vulnerable species like scalloped ribbonfish (Zu cristatus) and luvar (Luvarus imperials), deep-sea species including pygmy and spotted lanternfish (Lampanyctus pusillus, Myctophum punctatum) and other bioluminescent species (Cyclotone spp., Hygophum sp., etc).
The importance of the Balearic Islands
Along with the South Tyrrhenian, the Balearic Islands constitute the most important spawning area for bluefin tuna in the Mediterranean Sea, and is also one of the most important fishing grounds for this species.
Balearic waters are immensely important because they constitute a transition area for bluefin tuna moving from the Atlantic into the Medtierranean. Overfishing in this spawning area severely affects the population of bluefin tuna caught in the East Atlantic and even affects the West Atlantic stock, which has been catalogued by the International Union for Conservation of Nature (IUCN) as critically endangered.
Xavier Pastor, executive director of Oceana Europe, has once again stressed the need to act immediately in this area: “In the case of the Balearic Islands, we already have the information necessary to designate a reserve for bluefin tuna, and this would also benefit other species like swordfish. However, the responsible authorities refuse to be pioneers in implementing of the first reserve of these characteristics in the Mediterranean. There is absolutely no reason to delay this action, especially taking into account the critical situation of bluefin tuna in the entire North Atlantic.”
Oceana has video footage and photographs available