Priority Conservation Areas for the Longsnout Seahorse Hippocampus reidi Ginsburg, 1933, on a Tropical Coast

Seahorses are cryptic fish that can be found in several types of ecosystems. The microhabitat plays an important role in their lives, providing structure for many ecological functions. Taking into account that the influence of habitat loss will be mainly severe on species specialized in microhabitats, and habitat use might also be related to life stage, the present study aims to characterize the microhabitats used by the longsnout seahorse Hippocampus reidi along the Rio de Janeiro state coast, describing the breadth of the spatial niche, as well as the influence of benthic invasive species and abiotic factors on it, and proposing specific habitat conservation strategies. The present study was carried out in five areas of Rio de Janeiro state. Our results showed that habitat use by seahorses varied across the different areas, where there is a notable difference in niche breadth between adults and juveniles. Sepetiba Bay had a higher abundance of seahorse and microhabitat diversity, and a particular invasive species Schizoporella sp. seemed to be positively correlated to the seahorses' abundance. In addition, our results showed that Arraial do Cabo and Armação dos Búzios deserve greater attention and can be considered priority areas for conservation, and Araruama Lagoon needs specific conservation measures to protect the seahorses against future threats caused by urbanization.