Vis field base

In 2006 Blue World opened a new field project in the central Adriatic Sea, around the area of the island of Vis. The Vis archipelago, including the islands of Biševo, Sveti Andrija, Jabuka, Brusnik and Palagruža, and particularly the surrounding sea, has been identified as a well-preserved biodiversity hot-spot.  As such it should provide an insight into the life of the bottlenose dolphins in a relatively pristine environment with low anthropogenic disturbance.

Initially, this research was planned only as a time-limited scientific endeavour, but the fascinating scenery and biodiversity of the island and the richness of the surrounding sea created an impetus for a long-term study. The expansion of the research, both spatially and temporally, around the Vis archipelago, with study visits to neighbouring Lastovo Nature Park, is currently one of the priorities for the Blue World. The Vis field base is located in the village of Gornji Rukavac on the southern coast of the island of Vis, midway between the towns of Vis and Komiža.

Bottlenose dolphins are found in the archipelago on a regular basis. Groups observed had over 30 individuals, including females with newborn calves, indicating that the area represents a nursing ground.

Over the last three years research has revealed that a number of animals show high site fidelity as several individuals have been observed in consecutive years.  Although currently we cannot give a precise estimate of the number of animals dolphin sighting frequency is high. With more long-term data we will be able to identify the size and trends in the population.

In the area several other Cetacean species have been recorded – fin whale, striped dolphin, Cuvier’s beaked whale and Risso’s dolphin. In recent history the area was also inhabited by the common dolphin, which is now considered regionally extinct. During our surveys we also encounter other animals like giant devil rays, blue-fin tuna, swordfish, Eleonora’s falcons, Manx and Cory’s shearwaters, European shags among others. In the area there are occasional reports of sightings of the monk seal, great white shark and other endangered animals.

Bottlenose dolphins are protected by law in Croatia and have the Red List category “Endangered” but without evaluated trends. Their research and conservation has been listed as one of the priorities in Croatian and European nature protection. Therefore this research should help in understanding their true status in the Adriatic sea and help in the implementation of the Natura2000 priority actions for marine biodiversity.

Regular daily (whenever the weather conditions are positive) surveys are conducted from the field base in Rukavac bay on Vis island. Surveys are done by 6m inflatable boat with rigid, plastic keel. Boat is propelled by 4stroke 90HP engine.

Once at the sea, visual survey is carried out. Track and positions are taken by GPS and sea state and weather conditions are recorded. Once dolphin group is spotted a standardised data collection is carried out including the photo-identification of the individual animals in the group, group composition, behaviour etc.

Some additional data and samples are collected occasionally like inspection of the trawlers fishing in the area both for the presence of dolphins and their catch on-board the vessels, interviews with fisherman on dolphin-fisheries interaction, sampling of the dolphin faeces etc.

Although no stranded dolphins have been found in the area during last two years, a stranding would include a necropsy and sampling of the carcass carried out by a standard procedure.

All data collected in the field are stored in different digital databases and analysed using different statistical, photo-editing and GIS software.

For documenting a HD digital camera with underwater case is being used to film different situations either for scientific or scenic/visual purposes. A database of digital media is being developed and it includes clips of different situations, activities, animals and areas filmed on different locations in the Adriatic sea.

During our surveys we encountered interesting, rare, strange or beautiful animals. That includes schools of giant devil rays, blue-fin tunas, swordfish, Mediterranean flying fish, Eleonora’s falcons, Manx and Cory’s shearwaters, European shags etc. In the area most recently a great white shark has been observed and there are occasional reports of sightings of the monk seal.

In the area several other Cetacean species have been recorded – fin whale, striped dolphin, Cuvier’s beaked whale and Risso’s dolphin. In recent history the area was inhabited by common dolphin (one a resident species of the Adriatic sea), which is regionally extinct today.

For all additional information and a more detailed explanation of our work on Vis please contact us at:
Blue World - Vis, Gornji Rukavac 14, 21480 Vis, Croatia
vis@blue-world.org