This paper provides a case study of a threatened seahorse species, Hippocampus reidi, highlighting the importance of using ecological information to assist conservation and management initiatives. Underwater visual sighting data (50 x 2m transect) gathered along the NE, SE and S portions of the Brazilian coast revealed an unequal distribution across localities, perhaps related to harvesting pressure, and a mean density of 0.026 ind.m -2 . Our findings suggest some restricted spatial use by H. reidi, which was consistent with its estimated home range, and with re-sighting of specimens. Reproduction was recorded year-round, however productive peaks may exist. Components of habitat structure mostly used as anchoring points were mangrove plants, macroalgae, cnidarians, seagrass, sponges, and bryozoans. Conservation recommendations include: further characterization and mapping of habitats; assessment of availability and condition of microhabitats in selected areas, and studies on dispersal routes during initial life stages.Neste artigo apresenta-se um estudo de caso de uma espécie ameaçada de cavalo-marinho, Hippocampus reidi, enfatizando a importância de utilizar informações ecológicas nas ações de conservação e manejo. Dados de censo visual (transectos de 50 x 2m) obtidos nas porções NE, SE e S da costa brasileira revelaram uma distribuição heterogênea entre as localidades, talvez relacionada à pressão de coleta, e uma densidade média de 0.026 ind.m -2. Os resultados sugerem limitação no uso do espaço por H. reidi (consistente com a área vital estimada e com a re-avistagem de exemplares) e que a reprodução ocorre o ano inteiro, embora com possíveis picos. Os componentes da estrutura do habitat mais freqüentemente utilizados como pontos de ancoragem pelos cavalos-marinhos foram vegetação de mangue, macroalgas, cnidários, capim marinho e briozoários. Recomendações conservacionistas incluem caracterização adicional e mapeamento de habitats; avaliação da disponibilidade e condição dos microhabitats em áreas selecionadas, e estudos sobre rotas de dispersão durante as fases iniciais de vida.

Seahorses (Hippocampus spp.) are globally threatened by overexploitation and habitat destruction; they are also regarded as susceptible to heavy exploitation due to some of their life-history traits. From an economic perspective, they are fishes with high monetary value and marketability. Seahorses are now listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), to ensure that the international trade is not detrimental to the survival of wild populations; the effectiveness evaluation of these international controls needs comparable monitoring data, including evaluation of spatial and temporal trends. This study assesses the seahorse trade in Brazil, aiming to detect trends in catch levels, volumes and prices. Our main findings were: the dried trade was unregulated, without formal records, and primarily domestic, although records of unreported exports existed; it was primarily sustained by incidental captures in trawl nets. The live seahorse trade was mainly destined for exports, and regulated through national quotas. Between 2002 and 2009, mean prices for dried seahorses ranged from US$1.06 ± 0.46 (level 1 traders) to US$2.78 ± 0.68 (end-sellers) each, while mean prices for each live seahorse traded on the domestic market (

This paper presents novel sex-related characteristics in Hippocampus reidi, expressed as a prominent and pigmented keel (males only), and by a row of dorsolateral spots mostly (97.4%) found in males. While the keel was found even in the smallest males sampled, the dorsolateral spots appear to be associated with body size. Ex situ observations revealed that during courtship males highlighted both characters by turning pale their background body colour. Understanding such colour and behavioural patterns is relevant to increase our knowledge about sexual selection in a morphologically and biologically unique group of fishes.O presente trabalho descreve novos caracteres sexuais em Hippocampus reidi, expressos como uma quilha proeminente e pigmentada (machos apenas), e uma série de máculas dorsolaterais, encontradas principalmente (97,4%) em machos. Enquanto a ocorrência da quilha foi observada mesmo nos menores machos, a presença de máculas dorsolaterais parece estar associada ao tamanho do corpo. Observações ex situ mostraram que os machos realçam ambos os caracteres durante o comportamento de corte, ao tornar pálida a cor de base do corpo. Destaca-se a relevância da compreensão de tais padrões de colorido para o avanço no conhecimento relativo à seleção sexual em um grupo de peixes de morfologia e biologia singulares.