The ADP represents the first regular and consistent investigation of the social-ecology of any cetacean species in the Mediterranean Sea by means of rigorous photoidentification, behavioural and acoustic sampling techniques.

The research started in 1987 in the coastal waters of Croatia, focusing on a community of bottlenose dolphins frequenting the waters adjacent to the eastern shore of the islands of Losinj and Cres (Northern Adriatic Sea).

In March 1992 the Tethys Research Institute opened a permanent base in Veli Losinj, to carry out a year-round research program. Operations in Veli Losinj allow an effective monitoring of the local dolphin community through the collection of data on a day-by-day basis.

New dolphins are continuously identified based on natural permanent marks on their dorsal fin, while already catalogued individuals are frequently resighted. Occasionally the sex of some dolphins is determined, either from photographs of their genital area or through close association with a newborn. The dolphins are followed during their daily movements for long periods of time, in order to collect information on their behaviour with a standard procedure (behavioural sampling). This results in a progressive outlining of the individual dolphinsÕ social ecology and structure, as well as of their feeding habits, including behaviours in which interactions with fishing boats are involved.

Observations are supplemented by acoustic recordings of the dolphinsÕ vocalizations, with the goal of relating the different types of sounds produced to different activities and behaviours.

A summary of the field work conducted until December1994 includes:

- 388 days at sea, for a total of over 1700 hours
- 753 hours spent in direct observation and photography of 787 bottlenose dolphin schools of different size and composition
- the taking and cataloguing of 13806 slides
- the collection of 11807 behavioural samples of 3 minutes
- the inspection of the wake of 213 trawlingboats
- the post-mortem examination of 6 dolphins stranded in the area, with the collection of biological samples
- over 20 hours of recording of dolphin's vocalizations.

Cetaceans . . . Scientific findings