GROWTH AND FIRST MATURITY OF LINED SEAHORSE Hippocampus erectus IN CAPTIVITY

Relevant data are presented regarding the growth and size/age of appearance of gonads in females and marsupium in males and of first maturity in Hippocampus erectus. Pregnant males were captured and kept in captivity until the moment of the expulsion of the offspring. The juvenile seahorses were kept in captivity for 7 months, during which they were sampled monthly in order to determine the absolute growth and growth rates, and from the third month samples of gonads were taken from the females, to describe their gametogenic development.  At the end of the 7 months, the seahorses had an average size of 72.3 ± 4.0 mm. During the first two months the juveniles were fed with enriched metanauplii of Artemia as the only feeding and, with a period of one week of weaning, the seahorses were fed the rest of the time with live adult Artemia. During the weaning period seahorses experienced a decreased growth rate. The first oocytes begin to be observed in organisms from 40-50 mm size class, and appeared after the third month of life. In that same size class the presence of male marsupium was observed, time when is possible to evaluate the sex ratio. Mature females and males with the fully developed marsupium were observed from the size class of 60-70 mm, corresponding to the age of 5 to 7 months. This information is valuable for planning aquaculture programs for this species.