THE ENDANGERED MEDITERRANEAN COMMON DOLPHINS: IS THERE ANYONE INTERESTED IN THEIR CONSERVATION?
Once one of the most common cetacean species in the Mediterranean, the short-beaked common dolphin Delphinus delphis has declined throughout the region during the last 30-40 years.
by Giovanni Bearzi / Tethys Research Institute
Conservation problems for the species have been recognised since the 1970s. The UNEP Mediterranean Action Plan
(Barcelona, 1975) recommended strong conservation measures to protect the species but without specifying what these
should be. Determining the conservation status of Mediterranean common dolphins was cited as a priority in past
cetacean action plans of the IUCN Species Survival Commission.
The 2000-2010 IUCN Action Plan for the world's cetaceans noted that common dolphins had declined dramatically in
the central and eastern Mediterranean and stressed that conservation action was urgently needed to prevent extirpation
in this portion of the species' range.
In 2003 the Mediterranean population of common dolphins was classified as Endangered in the IUCN Red List of
Threatened Animals (www.iucnredlist.org).
In 2004, ACCOBAMS presented a comprehensive 90-page Conservation Plan for Mediterranean common dolphins,
that was "welcomed" at the 2nd Meeting of the Parties to the Agreement.
In 2005, the Mediterranean population of common dolphins was included in Appendix I of the Convention on the
Conservation of Migratory Species (Bonn Convention - CMS). The population was also already included in Appendix
II but the listing - formerly limited to a "western Mediterranean population" - was extended to the whole Mediterranean
population of common dolphins.
Despite all the expressions of concern, recommendations, strategic planning and scientific background produced, no
relevant action has been taken so far that may result in common dolphin recovery in the region. On the contrary, the
threats which are thought to be causing decline (primarily bycatch in fishing gear and prey depletion caused by
overfishing) are continuing to jeopardise the survival of relict groups and the Mediterranean population at large.
Unfortunately, the situation of common dolphins looks equally grim whether one looks at the problem from a regional
or local prospective.
The decline of common dolphins around the island of Kalamos, Greece
Seeing common dolphins was a frequent event around the island of Kalamos only ten years ago, when one could
frequently spot these animals from the coast. Tuna and swordfish were equally abundant. However, today common
dolphins around Kalamos (a EC Site of Community Importance) have become a rare sight. For instance, common dolphin
encounter rates declined 25-fold between 1997-2004. Tuna and swordfish have also vanished.
More than a decade of intensive research suggests that the main cause of common dolphin decline in the area is
overfishing of their prey, in combination with unsustainable levels of bycatch in fishing gear. Purse seine nets, in
particular, seem to be responsible for the local overexploitation and depletion of epipelagic stocks of sardines, anchovies
and other fish that are important prey for high-order predators such as common dolphins, tuna and swordfish. Prey
depletion by fisheries is ongoing and increasingly well-documented.
Despite all the expressions of concern, recommendations by ACCOBAMS and the IUCN, and scientific background
produced, no relevant action has been taken so far that may result in common dolphin recovery around Kalamos.
For more information:
Bearzi G., Politi E., Agazzi S., Azzellino A. 2006. Prey depletion caused by overfishing and the decline of marine megafauna in
eastern Ionian Sea coastal waters (central Mediterranean). Biological Conservation 127(4):373-382.
Bearzi G., Politi E., Agazzi S., Bruno S., Costa M., Bonizzoni S. 2005. Occurrence and present status of coastal dolphins (Delphinus
delphis and Tursiops truncatus) in the eastern Ionian Sea. Aquatic Conservation: Marine and Freshwater Ecosystems 15:243-257.
Bearzi G., Notarbartolo di Sciara G., Reeves R.R., Canadas A., Frantzis A. 2004. Conservation Plan for short-beaked common
dolphins in the Mediterranean Sea. ACCOBAMS, Agreement on the Conservation of Cetaceans of the Black Sea,
Mediterranean Sea and Contiguous Atlantic Area. 90 pp.
Bearzi G., Reeves R.R., Notarbartolo di Sciara G., Politi E., Canadas A., Frantzis A., Mussi B. 2003. Ecology, status and
conservation of short-beaked common dolphins (Delphinus delphis) in the Mediterranean Sea. Mammal Review 33(3):224-252.
