Research Product

This procedure provides a method to determine the effect of continuous exposure of a toxic material on sheepshead minnow embryos and fry: their survival and growth to adulthood, and spawning success. Spawning success is measured by the ability of fish to spawn naturally, number of eggs spawned, fertilization success, and survival of embryos and fry. The experiment requires from 4 to 6 months. The primary advantage of this test is that results, when compared with those of acute tests with this species, can be used to calculate an application factor. This factor, used to assess relative chronic hazards of materials, is important in establishing water quality criteria. This test has several limitations and should not be considered valid in assessing toxicity of all materials. Sheepshead minnows can tolerate low dissolved oxygen and wide ranges of temperature and salinity. Therefore, toxicity tests using this fish may underestimate the toxicity of materials that alter these environmental conditions. Materials tested should mix well with water. Insoluble or highly turbid materials mix poorly, and their toxicity may be under- or overestimated.