A CONSPICUOUS POPULATION OF THE LONG-SNOUTED SEAHORSE, HIPPOCAMPUS GUTTULATUS (ACTINOPTERYGII: SYNGNATHIFORMES: SYNGNATHIDAE), IN A HIGHLY POLLUTED MEDITERRANEAN COASTAL LAGOON

Background. Seahorses are considered vulnerable and endangered fish species in many parts of the world. We found a conspicuous and stable population of Hippocampus guttulatus Cuvier, 1829 in the Mar Piccolo of Taranto (Ionian Sea), known of its substantial pollution a nd fluctuations in environmental parameters. The aims of our study were to demonstrate the role of habitat protection in the conservation of this species, the adaptabil- ity of the long-snouted seahorse to the water pollution and variable physico-chemical parameters, as well as the habitat preferences of H. guttulatus under particular conditions of this coastal lagoon. Materials and methods. The areas of diving were randomly selected within both parts of the Mar Piccolo o f Taranto. Observations were based on snorkelling and scuba diving at different depths from 0 through 4 m. For each dive, in each inlet, all types of environment were explored, divided in four categories based on the nature of the substrate. From the summer of 2011 to the summer of 2013, a total of 23 days of observations were car- ried, for a total period of 69 h. Results. A total number of 196 sightings of Hippocampus guttulatus were recorded. The data show a clear pref- erence o f the fish studied for the artificial hard substrates, piers and wharves in particular. Only 3 specimens were observed on algal meadows. The western part of the lagoon harbours the largest number of the specimens. Concerning both depth and the three years period, no significant differences were found in the abundance. Conclusion. This study highlights the ecological importance of the coastal lagoon of the Mar Piccolo of Taranto. We report quantitative data about t his population of seahorses with considerations and discussions about the pres- ence and distribution of the specimens, their preferred substrates, and the peculiar polluted environment that they inhabit. Future studies are necessary to better understand the role of habitat protection for seahorses and to improve protection measures for the management and conservation of the species.