Population characteristics of two seahorses, Hippocampus coronatus and Hippocampus mohnikei, around seagrass beds in the southern coastal waters of Korea

Abstract

Population characteristics of two seahorse species, Hippocampus coronatus and Hippocampus mohnikei, in seagrass beds in the southern coastal waters of Korea were determined based on field observations. In Zostera beds in the Yeosu area, there was a mean density of 2.9 seahorses per 1,000 m2 for H. coronatus and 1.4 seahorses per 1,000 m2 for H. mohnikei. The greatest numbers of young individuals of both species were observed in July, with numbers decreasing through November. The male:female sex ratio was 1:1.6 for H. mohnikei and 1:1.7 for H. coronatus. Breeding males of H. coronatus and H. mohnikei were observed from July to November and from July to September, respectively. Within the study site, the populations of the two seahorse species exhibited low density and patchy distributions, with variation in temporal abundance being significantly correlated with water temperature. The findings of this study provide the basis for future research on the population status of H. coronatus and H. mohnikei in seagrass beds.