CROATIAN FAUNA - COMMON BOTTLENOSE DOLPHIN

COMMON BOTTLENOSE DOLPHIN The common bottlenose dolphin (Tursiops truncatus) is a mammal from the toothed-whale group. It has a distinctive fusiform and hydrodynamic body shape that enables it to swim very fast. The strong tail fluke is used for swimming, while its pectoral flippers are used to turn and stop, and the rounded dorsal fin stabilizes the body. The common bottlenose dolphin breathes air through the blowhole on the top of its head. Its back is mostly darker blue-grey in colour, and its belly is lighter. The dolphins in the Adriatic Sea usually reach three meters in length, and up to 200 kg in weight. The average life expectancy of common bottlenose dolphins is more than 30 years, and sexual maturity occurs at 6 to 7 years of age. Females bear only a single calf every three to five years but may have several of them throughout their lifetime. The coastal areas in the Adriatic and the Mediterranean Sea are inhabited by smaller communities of common bottlenose dolphins. Within such communities we often find groups of five to six dolphins on average. Adult males can mostly be seen in smaller groups or in pairs. Females with calves are usually in larger groups of 8 to 10 dolphins, for protection. The females in such groups are often related. The longest study of a community of common bottlenose dolphins in the entire Mediterranean has been conducted on Lošinj since 1987. Common bottlenose dolphins feed on fish and cephalopods. Sound is particularly important to them, and they use it to communicate. Echolocation is used to search for prey – by emitting a high frequency sound that reflects from obstacles, and thus using sound to “light up” their surroundings and easily recognize obstacles and prey. Numerous human activities endanger common bottlenose dolphins: marine pollution, noise pollution, harassment, overfishing, and bycatches in fishing gear reduce their populations. In order to reduce catch losses for fisheries and the incidence of injuries as well as the entanglement and death of dolphins in fishing gear, the Blue World Institute of Marine Research and Conservation is, together with nine partners from Italy, conducting from 2020 to 2024 the project “LIFE DELFI – reduction of interaction with fisheries”, worth 4.8 million euros, co-financed by the European Union with the LIFE program and the Office for Cooperation with NGOs of the Government of the Republic of Croatia.