Seagrass habitat characteristics of seahorses in Selayar Island, South Sulawesi, Indonesia

Seagrass beds are an important habitat for seahorses, a group of small-sized fishes that are named for the horse-like shape of their heads. This study paid attention to the role of seagrasses in seahorse occurrence and their size distribution because this habitat plays a crucial role in their life cycle providing food and shelter from predators. Seagrass characteristics of the habitat of two seahorses, Hippocampus barbouri and H. kuda, in Selayar Island were mapped and determined based on field observations. There were three main seagrass beds used as seahorse fishing grounds around the island, namely Labuang, Jahi-Jahi, and Binanga Benteng, with seagrass percentage cover of 33.14±2.44%, 29.02±1.90%, and 4.73±1.43%, respectively. Seagrass species occurring in the seahorse fishing areas were Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, C. serrulata, Halophila ovalis, and Halodule uninervis. A high percentage cover of macroalgae (37.22±5.75%) was found in the seagrass beds of Binanga Benteng. Macroalgae found were Padina, Halimeda, and Dictyota. During the study, we found in total 142 individual H. barbouri and 19 H. kuda, with the highest abundance in the seagrass beds of Binanga Benteng followed by Jahi-Jahi, and the lowest abundance in Labuang. Moreover, the size of both male and female of H. barbouri was also consistently larger in Binanga Benteng, followed by Jahi- Jahi, and then Labuang, suggesting the importance of habitat complexity for this species. The male: female sex ratio was 1:1.2 for H. barbouri and 1:0.4 for H. kuda. In addition to the seagrass meadows, this study also revealed the importance of macroalgal beds in providing habitat for seahorses. This finding provides the basis for future research on the population status of two vulnerable species, H. barbouri and H. kuda in different seagrass habitat complexity in order to determine management priorities for conservation.