Distribution of Seahorses ( Hippocampus spp.) Along the Brazilian Coast Highlights Habitat Associations and Regions of Conservation Interest

ABSTRACT Understanding the geographic distribution and habitat associations of seahorses is fundamental for developing effective conservation strategies, yet comprehensive syntheses at national scales remain scarce. Brazil encompasses a wide diversity of coastal and marine ecosystems inhabited by three seahorse species ( Hippocampus reidi , H. erectus and Hippocampus patagonicus ), but available information has remained fragmented across scientific publications, museum collections, technical reports and monitoring programmes. Here, we compiled and synthesized occurrence records from multiple data sources to provide the first nationwide overview of seahorse distribution along the Brazilian coast. The assembled dataset was used to describe spatial patterns of occurrence, habitat associations, bathymetric distribution, species composition and representation within protected areas, while identifying regions that combine documented seahorse occurrence with distinctive habitat characteristics and important knowledge gaps. The compiled records show clear differences in documented habitat associations and bathymetric occurrence among species, extending from estuarine and mangrove habitats to coastal reefs and the continental shelf. H. reidi was predominantly associated with estuarine and shallow coastal environments, whereas H. patagonicus occurred mainly on the continental shelf and H. erectus occupied intermediate coastal habitats. The synthesis also highlights regions that concentrate species records, habitat diversity or unique ecological characteristics, including Ilha Grande Bay and the continental shelf between Torres and Rio Grande, emphasizing their relevance for future ecological research and conservation planning. Rather than estimating population abundance or conservation priority, this study provides a comprehensive biogeographic baseline for Brazilian seahorses by integrating occurrence records collected over multiple decades. This synthesis establishes an important reference for future monitoring, ecological investigations, species distribution modelling and evidence‐based conservation initiatives along the Brazilian coast.