Maturation and spawning induction in Hawaiian opihi Cellana spp. by hormone GnRH

Gonadotropin releasing hormone (GnRH) is a neuropeptide hormone whic plays an important role in control of the reproduction among vertebrates and some work is showing that it is active in invertebrate species. We matured and spawned the Hawaiian opihi Cellana spp. by using salmon GnRH analogue. In the first experiment on maturation, twelve adult opihi (3.18+/-0.23cm, shell length) were injected weekly with salmon GnRHa at dose of 250ng.g-1 body weight (BW) for a 6-week period. Gonad development was assessed using gonadosomatic index (GSI) and histological techniques. GSI incorporated with histological analysis showed that the gonads reached full maturation after 4 weeks. GSI increased significantly (31%) in comparison to the control group of saline solution injection did not produce any maturity in opihi. For the spawning trial, eight ripe opihi were administered a single injection at dose of 1000ng.g-1 BW. The results showed that an average of 33% of the animal spawned in 4-6h after hormone injection. Fertilized eggs developed through embryo and to the com plete larval stage of veligers. Our preliminary findings in this study provide a new aspect of hormone controlling reproduction of opihi, which could be applied in opihi aquaculture.