Effects of food, temperature and light intensity on the feeding behavior of three-spot juvenile seahorses, Hippocampus trimaculatus Leach

Abstract: Seahorses are an important commercial and cultural commodity for medicinal and ornamental use. The effects of food, temperature and light intensity on the feeding behavior of juvenile seahorses, Hippocampus trimaculatus Leach, were investigated. All four age groups of juveniles (5-day, 10-day, 15-day and 30-day groups) tested had only one feeding peak in the afternoon, but the time of the peak differed significantly among groups. The major feeding peak of the 5-day and 30-day groups was at 1430h, the 10-day group at 1630–1830h and the 15-day group at 1630h (P <0.05). For the first 3days, the juveniles preferred copepod (Pseudodiaptomus annandalei) nauplii and Moina (Moina mongolia) nauplii. They altered their feed to copepodites from 4days to 10days and, over 10days, they began to eat copepod adults and Moina. The abilities of juveniles to digest and assimilate their feed were related to developmental stages. It took to digest the feed entirely, 2.5h at 5days postpartum, 3.5h at 10days postpartum and 4h at 15days postpartum. Water temperature affected significantly the feeding rate of juveniles (P <0.01) with an optimum temperature at 26°C. Light intensity also affected the feeding rates of different juvenile groups (P <0.01): 1834lx was the best light intensity to feed juveniles of the 1-day group, 1014lx in the 5-day group and 510lx in the 10-day group. The relationship between the standard length and the wet weight of juveniles was found to be exponential: W =10−2.72211SL2.690562 (R 2 =0.984064, P <0.01). The results obtained in this investigation contribute to the aquaculture potential of H. trimaculatus. [Copyright &y& Elsevier]