Effect of different Artemia enrichments and feeding protocol for rearing juvenile long snout seahorse, Hippocampus guttulatus

The aim of this study was to determine suitable Artemia enrichment and feeding protocols for the rearing of juvenile long snout seahorse, Hippocampus guttulatus from birth. The first phase of the project, examined the effect of two different Artemia enrichments treatments (DHA-Selco®, and Chlorella sp.) on the growth performance and survival of early-stage juvenile H. guttulatus. DHA-Selco® enrichment of Artemia resulted in a null survival at 10 days post parturition (DPP) whereas the use of Artemia enriched with Chlorella sp. resulted in 20% survival at the end of 60 DPP. The second phase of the study (60 to 120 DPP) reported the progressive feed transition of juvenile seahorse from Artemia to live shrimp (Palaemonetes varians) and from live to frozen shrimp and its effect on growth performance and survival of the juveniles. Overall, the mean standard length of juvenile H. guttulatus increased from 1.4 ± 0.05 cm at release from male's pouch to 12.4 ± 1.2 cm at 120 DPP. Mean juvenile wet weight increased from 4.2 ± 0.2 mg to 4133 ± 1230 mg in that same period. Length, wet weight, daily weight gain and thermal-unit growth coefficient were used to characterise juvenile H. guttulatus growth performance, which was found to be similar to that of published accounts for other juvenile seahorse species at the same life stage. This study is the first record of successful rearing of H. guttulatus juveniles in captivity, and offers a promising starting point to improve the rearing techniques to successfully breed this candidate aquaculture species.