Assessment of embryo characteristics, hatchability and survival of cuttlefish (sepia hierredda) in recirculating culture systems

Abstract

Globally, fish stocks are declining and the case is not different in Ghana, where small pelagic and some demersal stocks have also declined. It is therefore expedient to explore the culture potential of some economically valuable marine species for commercial production to augment fisheries production and improve coastal livelihoods within the context of promoting Ghana‘s blue economy. Cuttlefish is the most exploited cephalopod in the Ghanaian fisheries and the country is renowned as one of West Africa‘s top producers and exporters of cuttlefish. In this study, the embryo characteristics, hatching success, and survival of cuttlefish were assessed in recirculating aquaculture systems. The research involved the collection of fertilized eggs from near-shore waters of two coastal communities and culturing them in recirculating aquaculture systems (systems A and B) with three replicates each. System A contained eggs collected from cuttlefish landings at Nungua in the Greater Acca Region whereas system B contained eggs collected from Elmina in the Central region of Ghana. The embryos from Elmina showed significant growth evidenced by an increase in size during the period of incubation (p<0.05) whereas the embryos obtained from Nungua experienced little growth. The mean weight recorded for the embryos in system B was 0.956 ± 0.449 g whereas, in system A, embryos had a mean weight of 0.4776 ± 0.0603 g. The eggs hatched between 12 and 14 days after incubation. Eggs collected from Elmina had a hatching rate of 70% whereas those from Nungua had a lower rate of 16%. The survival of the species under culture was very low for eggs collected from Nungua and Elmina, with heavy mortalities (100%) occurring within 14 days after hatching.