5.1 In certain toxicity tests during which small aquatic animals must be fed, the food of choice is often live brine shrimp nauplii because of their availability, ease of use, and presumed good nutritional quality. In addition, many test species that are cultured or held in the laboratory must be fed prior to toxicity testing, even if they are not fed during the test.

5.2 Brine shrimp nauplii can be readily hatched in the laboratory from cysts that are obtained naturally from many geographical areas around the world. Cysts from a few of those areas are available commercially, but might represent two or more species of brine shrimp (1).

5.3 Nauplii of different strains of the same brine shrimp species from different geographical areas can differ substantially in their nutritional value, contaminants, and acceptability as a complete food for the life stage of the species to which they are fed (3-8).

5.4 The results of a toxicity test can depend on the brine shrimp nauplii used as food (9) . It is desirable to determine prior to use whether a particular batch of brine shrimp is of adequate quality for the test organisms.

5.5 The primary requirements of acceptable brine shrimp are that they are an appropriate size for the test organisms, have adequate nutritional value, and do not contain excessive concentrations of contaminants. Whether a given lot of brine shrimp meets these requirements for a given species can only be determined by a feeding assay.

5.6 Standardization of the hatching, harvesting, testing, and using of brine shrimp will probably increase the reproducibility of results of toxicity tests with some test species by decreasing the use of unhealthy organisms caused by feeding them poor quality brine shrimp.