Paul Silva, the senior conservation scientist, conducted a tour of the facility and explained the steps in raising fish, from spawning of the adult brood stock to release of fingerlings into the wild. Considerable research has gone into methods for raising fish successfully, and these methods are continually being improved and refined. When the adults spawn, the fertilized eggs are collected and kept in incubation tanks for three days. The hatched larvae are then transferred to ponds, where they feed and grow for approximately 30 days, at which time they are harvested and transported to various bays and lakes in Texas. In order to enrich the plankton supply, the ponds are fertilized with nitrates, phosphates, and organic matter.
Fertilizer causes the natural algae to experience rapid population growth, known as a bloom.
The algae serve as food for rotifers and copepods. The young fish feed first on rotifers, then on copepods. Adding fertilizer to plants is a common practice and the basis for numerous science projects. Many students do not realize that aquatic plants will also respond to fertilizer. Teachers will need to have access to a natural water source, either ponds, lakes, or bays.