(August 14, 2018) The Nassau grouper broodstock at Tropic Seafood, Ltd., has spawned again. This was the second large spawning event within 6 weeks. All of the spawning events that occur at Tropic Seafood, Ltd., are “All-Natural Spawning Events” which occur without the use of hormones (to induce spawning). It has taken over three years for the broodstock at Tropic Seafood, Ltd., to be conditioned to spawn naturally in captivity.
During the June 21st series of spawning events, the Nassau grouper spawned consecutively over a period of 5 nights, producing tens of millions of eggs. If the eggs cannot be utilized in the hatchery at Tropic Seafood, Ltd., they are released into the sea as fertilized viable eggs. During the most recent series of spawning events at Tropic Seafood, Ltd., fertilized eggs were transferred to incubators in order to produce Nassau grouper larvae. Due to the abundance of viable larvae produced in the hatchery, approximately 2.5 million newly hatched strong-swimming larvae were released into the sea, which were not needed to conduct cultivation trials at the hatchery.
Newly hatched larvae (called yolk-sac larvae, because they carry a yolk sac that contains a single drop of bio-lipid oil) can live off their yolk sacs for nourishment, for about four days after hatching, before their mouth parts become large enough and strong enough to accommodate live food (prey) such as zooplankton. Tropic Seafood, Ltd., maintains live cultures of three different types of live food (copepods, rotifers and artemia) and live phytoplankton which the live zooplankton need to eat. Efforts to culture the Nassau grouper larvae are ongoing with very favorable results.