Apalachicola Bay
System Initiative

In order to provide animals for researchers or for restoration, the hatchery begins with animals ready to spawn. Either the animals are collected from the field with ripe gonads and stored in cold water to preserve this gonad, or animals that are not quite ready are kept in warmer water and provided high amounts of food. These adult animals kept in the hatchery to use for spawns are called “broodstock.”

To spawn, animals are triggered to release gametes into the water, a process called “broadcast spawning.” The hatchery uses thermal cycling, or increasing and decreasing water temperature, to trigger broadcast spawning. Then, gametes are collected and mixed together to fertilize the gametes.

When they fertilize, the gametes undergo cellular division and develop into veliger larvae. This stage is characterized by a “velum,” which is an organ that allows larvae to swim and eat. The larvae, which usually number in the millions, are cared for every day, including given new water, fed, and measured for growth—a process called “grading” in the hatchery.

After about 2 weeks as veligers, the larvae start to show “settling cues,” signs that they are ready to metamorphose. They develop a light sensitive eyespot and a foot they use to crawl around. When hatchery technicians see these signs under the microscope, we know they need to go into our setting systems!

The hatchery can set larvae as “spat-on-shell” by providing oyster shells for the larvae to set on or as “single sets” by providing cultch. The method depends on what researchers and restorationists need! The larvae use their foot to decide where they want to be and then cement themselves into place to begin their metamorphosis. The larvae lose their foot and velum and develop into juvenile oysters!

Then the spat are grown until they go into the field for restoration or to researchers for their work. Our animals have been used to develop growth and survival estimates for Apalachicola Bay oysters, to research physiological tolerance and effects of environmental stress, and to compare to wild animals!