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Distribution and abundance of megafauna in the Adriatic Sea: relevance for identification of important marine areas

In order to assess the presence, distribution and abundance of cetaceans and sea turtles, the entire Adriatic Sea was surveyed for the first time between 31st of July and 16th of August 2010. In total approximately 13, 000km of transects were conducted in a Partenavia 68, a small high-winged twin-engine plane, equipped with bubble-windows. During the survey additional data on other top- predators, such as rays, sharks, swordfish and various species of tuna was also collected. Observations of cetaceans included: 139 sightings of Bottlenose dolphin (Tursiops truncatus), 83 of Striped dolphins (Stenella coeruleoalba), 11 of Risso’s dolphin (Grampus griseus), one of Cuvier's beaked whales (Ziphius cavirostris), one of Fin whale (Balaenoptera physalus), one unidentified large cetacean and eight undefined small cetaceans. Of the other large vertebrates, 1, 020 sightings of turtles believed to be Loggerhead (Caretta caretta), 44 of giant Devil ray (Mobula mobular), 24 of unidentified rays, 41 of mostly unidentified sharks, 11 of Swordfish (Xiphias gladius) and numerous of groups of different species of tuna. Preliminary data analysis indicate the following main points: a) the entire northern Adriatic, including the Croatian islands archipelagos, are an important habitat for bottlenose dolphins ; b) a high summer density of sea turtles in the northern Adriatic was confirmed, but this species is widely distributed throughout the entire basin ; c) the central and southern Adriatic is an important habitat for pelagic megafauna, particularly rays and deep water cetacean species, such as Striped dolphins, Cuvier's beaked whales, Risso's dolphin and Fin whales ; d) the range of all of the species observed is extremely wide and transboundary in nature with their distribution reflecting the oceanographic features of the basin. The regional conservation goals should bear this points in mind when considering practical methods to protect these species.

megafauna; Adriatic; marine conservation; aerial survey; cetacean; marine turtle

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