THE striped dolphin (stenella coeruleoalba), the most numerous species of its kind in the Mediterranean - numbers last summer stood at between 17 and 20'000 - is threatened by a viral epidemic originating in the Atlantic and carried to the Med by another dolphin species known in Spanish as the black cauldron (globicephalinae).
The report on the health of the dolphin population, researched over a five-year period along the coast of Valencia has been a joint venture operation involving the regional ministry for the Environment, the University of Valencia, a marine biology Institute, and the Oceanographic Centre in Valencia. The technical department which had worked on the findings said that scientists had first been alerted to the virus which can prove fatal to dolphins, as early as 1990 when an epidemic killed nearly 2'000 striped dolphins in the Mediterranean. Investigators said yesterday they need to know more about the behaviour of the virus. Ironically, the second variety of dolphin which carries the virus, is not nearly so badly affected by it. A spokesman explained that the calderón negro variety of dolphin develops an immunity against the virus as do human beings who eat any fish which are caught in waters where the virus is rife.
Results of the study were based on 94 sightings recorded along 2'730 miles of patrolled sea lanes off the Valencian coastline. Specialists noted eight different dolphin species amongst the 1'666 creatures which came into view. Investigation centred around the area of the Continental shelf where it joins the sea bed. The key methods used for locating dolphins involves the use of the hydrophone, a mechanism which enables humans to tap the high pitched squeaking sounds which the dolphins emit under water and which can be heard over a distance of 4 to 5 km.