Teach a man to fish and we may increase seahorses’ protection: evidence from citizen science and spatial ecology in the Italian Hippocampus species

Citizen science and spatial ecology analyses can inform species distributions, habitat preferences, and threats in elusive and endangered species such as seahorses. Through a dedicated citizen science survey submitted to the Italian diving points, we collected 115 presence records of the two seahorses occurring in this country, Hippocampus hippocampus and H. guttulatus. This data was then used to map the ecological features of these poorly known species and quantify the effects of current human activities on their habitat suitability through geographic information systems and ecological species distribution modelling. Our results indicated a quite continuous suitable area along the Italian coasts with a major gap in the central Adriatic Sea (Emilia-Romagna and Marche) in both seahorses. They co-occurred in most of their distribution, particularly in the central and southern Tyrrhenian coasts, and their ecological niches resulted to be significantly similar but not equivalent. The least-cost paths of both species were concentrated in the Southern Italy (Apulia, Calabria, and Sicily), suggesting that more data is needed to improve the spatial resolution of the available information, especially in the Northern and Central Italy. Human activities affected 35% and 41% of the H. hippocampus’ and H. guttulatus’ habitat suitability, respectively, while only 31% and 34% of their potential distribution, respectively, is protected by the existing system of conservation areas in Italy, in line with the seahorses’ worldwide average. In particular, the central Adriatic Sea represents a critical area where the occurrence of these seahorses is lower and the anthropic impact is higher. Considering all the Italian regions, fishing effort is the main human activity impacting both the seahorses. Our findings directly assist more efficient conservation actions. We encourage the application and interaction of citizen science and spatial ecology analyses to facilitate the assessment and sustainable management of elusive