A MINIATURE HATCHING SYSTEM FOR EVALUATING CHEMICAL TREATMENTS ON FISH EGGS

We developed a miniature egg hatching system to evaluate chemical trea tments on fish eggs. The system was designed to provide scientifically reproducable data according to good laboratory practices as opposed t o other hatchery systems that are designed solely for fish production. A detailed explanation of the construction of this test apparatus is provided with insight into potential applications of the system in tox icology or water research. The test apparatus was composed of a headbo x, miniaturized egg hatching jars, and glass aquaria. The test system was supplied with a continuous flow of well water that entered a headb ox and then flowed by gravity to the egg hatching jars. A three-way st opcock valve located between the headbox and egg jars directed water f rom the headbox to the eggs or administered premixed chemical solution s during treatments. The effluent from the egg jars flowed into glass aquaria that collected hatched fry. The aquaria effluent flowed throug h a carbon filter treatment system. The miniaturized system is portabl e and can be used to culture or to conduct toxicological studies on ea rly life stages of fish. Our test system was as efficient as larger-sc ale systems in culturing eggs and fry and will reduce the cost of eval uating therapeutants or toxicants in acute or chronic exposures.