The aquaculture potential of Black Grouper (Mycteroperca bonaci ) within the southeastern United States has yet to be realized mainly due to challenges with their aggressive behavior with fellow tank inhabitants, limitations in space for adequate long term broodstock holding, and success in simulating natural spawning conditions. The College of the Florida Keys Southernmost Marine Aquaculture and Research Training (SMART) center located in the heart of the Florida Keys National Marine Sanctuary has worked with the M.bonaci species since awarded grant funding by the Gulf States Marine Fisheries Commission in 2020. Titled: ‘From Guts to Glory’, the project focuses on housing and maturing female brood (45cm-75cm) in an indoor recirculating aquaculture system equipped with natural spawning stimuli (photoperiod control, temperature regulation, and audio stimulus with male courtship calls) and using cryogenically preserved male M.bonaci gametes for in-vitro fertilization.
Alternating between diets for our inhouse female broodstock, we saw an average growth of 0.16mm per day since their initial acclimation into our 2,700-gallon indoor RAS in early April 2022. The broodstock maturation diet alternates between threadfin herring (Opisthonema oglinum ), pink shrimp ( Penaeus Duorarum ), and homemade “maturation sausages” made from formulated dry powder (MadMac ) mixed with raw ground seafoods. Batches of our maturation sausages include ground threadfin herring, pink shrimp, shortfin squid (Illex illecebrosus) and vitamin additives: garlic extract (500mg) for appetite stimulation and Super B Complex for immune support.
To prepare for winter spawning in 2024, we will begin our natural spawning simulation conditions by lowering their in-tank temperature to reflect the change in seasons. These “seasons” begin with a 2-month summer at 29°C to increase metabolism followed by a steady decline towards a prolonged winter at 21°C . This period of controlled winter will urge the brooding females into a state of egg production where injectable hormones will be used to induce spawning in tandem with the natural spawning stimuli. Once gravid, females will be strip spawned inhouse and in- vitro fertilization will be attempted for the first time with the M.bonaci species.