15 June 2011

Common dolphins are becoming rare in the Mediterranean

The time has come to turn good intentions into actual conservation action

Once one of the most abundant cetacean species in the Mediterranean Sea, the short-beaked common dolphin (Delphinus delphis) has declined throughout the region since the 1960s. The primary causes of this decline include prey depletion caused by overfishing and incidental mortality in fishing gear. Today, common dolphins survive only in small portions of their former Mediterranean range, while in most areas they have become rare or are completely absent.

Common dolphins are no longer found in the northern Adriatic Sea, where they used to be abundant. Their disappearance from this region was prompted by systematic culling campaigns and other takes having occurred between the second half of the 19th century and the 1960s, and habitat degradation combined with excessive fishing in subsequent years. Common dolphins, however, still inhabit parts of the Mediterranean Sea, where either relic groups or important population units are known to survive. Most or all of these groups are now facing significant threats.

In the Inner Ionian Sea Archipelago, common dolphins declined tenfold between 1995 and 2007. Scientific studies showed that decline in these waters of western Greece was due primarily to prey depletion resulting from intensive over-exploitation of the local fish stocks. Based on this evidence, science-based measures have been proposed to prevent eradication of dolphins and further damage to marine biodiversity. A Call for Action signed by a number of national and regional NGOs was made in 2009, to no avail. The signatories stressed that fisheries management measures within "Natura 2000 sites" are possible under the Common Fisheries Policy. Such management measures are further advocated by Council Regulation (EC) No 1967/2006, concerning the sustainable exploitation of fishery resources in the Mediterranean Sea.

The signatories of the Call recommended a series of urgent actions to be taken within the Inner Ionian Sea Archipelago, that is a Natura 2000 Site. These actions included inter alia 1) a strict enforcement of national legislation and appropriate penalties for illegal fishing, 2) an immediate temporal restrictions on purse seining and trawling, to ensure that these fisheries are fully sustainable and do not harm the ecosystem and its biodiversity, 3) the prompt implementation of the ban of beach seining, as demanded by Council Regulation 1967/2006 (beach seining is known to devastate ecosystems and has been banned in most EU Countries), and 4) the adoption of larger mesh size for all bottom-set nets, in order to increase selectivity.

Thus far, no action was taken in the Inner Ionian Sea Archipelago. The failure of this and other attempts to promote the recovery of common dolphins in portions of the Mediterranean Sea where these animals have declined shows how difficult it is to move from words to actual implementation of conservation measures, even when there is a plethora of studies, published scientific information and detailed action plans to inform management.

For other parts of the basin and for areas with poor information, reducing overfishing and preventing incidental mortality in fishing gear would certainly contribute to common dolphin recovery. The question, however, is whether effective implementation of management action can occur before the Mediterranean common dolphin population shrinks even further — its decline becoming irreversible.

The number of international calls and authoritative recommendations produced over the years to "save" the common dolphin is impressive — offering a remarkable example of "marine conservation on paper". In 2003 the Mediterranean population of common dolphins was classified as Endangered in the IUCN Red List of Threatened Animals. In 2005, the Mediterranean population of common dolphins was included in Appendix I and II of the Convention on the Conservation of Migratory Species (Bonn Convention - CMS). In 2007, the Parties to UNEP’s Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic Area (ACCOBAMS) were “deeply concerned that despite the strong scientific evidence, strategic planning and multiple expressions of concern and recommendations (...) insufficient action has been taken to ensure recovery of the common dolphin in the region”. Similar concern and recommendations were reiterated in 2010. Although the Mediterranean riparian states were repeatedly urged to implement a Conservation Plan for common dolphins issued in 2004, and requested to introduce activities into their national action plans, no significant steps were taken.

In view of the international calls to protect common dolphins, and considering the scientific evidence of threats posed by fisheries mismanagement to this cetacean species and its habitat, governmental bodies are obliged to take action to reduce fishing pressure and limit the use of fishing gears that can have harmful effects. Management measures are urgently needed to allow for the recovery of endangered marine megafauna. Such measures should include the full and rigorous implementation of EC instruments that are binding for EU Member States — including inter alia the EC Habitats Directive and the Marine Strategy Framework Directive.

A rigorous enforcement of the existing regulations and appropriate penalties for illegal fishing would prove beneficial to the conservation of Mediterranean common dolphins. Measures to eliminate entanglement in pelagic gillnets (driftnets) are particularly important. Considering that driftnetting is illegal as of roughly two decades, what is most needed is strict enforcement of the international ban within and beyond EU waters.

Background information:

Bearzi G., Reeves R.R., Notarbartolo di Sciara G., Politi E., Cañadas 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.

Bearzi G., Agazzi S., Gonzalvo J., Costa M., Bonizzoni S., Politi E., Piroddi C., Reeves R.R. 2008. Overfishing and the disappearance of short-beaked common dolphins from western Greece. Endangered Species Research 5:1-12.

Bearzi G., Notarbartolo di Sciara G., Reeves R.R., Cañadas 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.

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