Effects of food on growth and gonadal development of seahorse Hippocampus sp.

Abstract

Hippocampus sp. has received attention as a source of aquarium and ornamental trade. Seahorses have been threatened from non-target fisheries, habitat loss and traditional Chinese medicine (TCM). In response to concern about a decrease of population in the wild, an aquaculture of this species may provide the seahorse numbers for the commercial demands. However, one of the critical problems in aquaculture is the proper dietary for growth and their development. Therefore, this study was conducted on different types of preys on survival rates, growth rates and gonadal development in Hippocampus sp. during the day of birth until the 31day after birth (DAB). The newborn Hippocampus sp. was reared under the optimal environmental conditions at the hatchery of Phuket Marine Biological Center (PMBC). The feeding treatments provided to newborns Hippocampus sp. were Artemia, wild Mysis spp., shrimp larvae and enriched copepod. The study conducted into 2 aspects: growth rates and survival rate, and gonadal development. In the case of Hippocampus sp. growth, none of the Artemia-fed group survived. The Mysis-fed group has the highest in growth rates and survival rates followed by the shrimp larvae-fed group and enriched copepod-fed group. For gonadal development, only ovaries of Hippocampus sp. were observed under histological level. The duration of oocyte growth in Mysis-fed group was shorter than the shrimp larvae–fed group and the enriched copepod-fed group, respectively. The result of growth rates and gonadal development are also related to highly unsaturated fatty acid (HUFA) contents in preys, which was observed high contents HUFA in Mysis spp., shrimp larvae and enriched copepod, respectively. The results of this study demonstrated that the Mysis spp. and shrimp larvae could be provided as an optimal prey for Hippocampus sp. growth and gonadal development. Therefore, this feed could be applied to improve the seahorse aquaculture in the future.