Laboratory Technique for Obtaining Fathead Minnow Eggs for Use in Toxicity Experiments

Abstract

A laboratory technique for collecting freshly fertilized eggs of the fathead minnow (Pimephales promelas) has been developed for use in toxicity testing of radioactive materials or other environmental pollutants. The fathead minnow egg was selected as a test organism because the period of embryogenesis is relatively short, the number of eggs per spawning is sufficiently large to provide a test group and a control group, and the size of the parent fish is compatible with laboratory facilities. Under a controlled laboratory environment, eggs are available all year. Nesting sites were constructed by cutting plastic pipe in half and covering the inside of the pipe with 1-mm-thick translucent polyethylene. The polyethylene with the eggs attached was removed from the shelter and cut into two pieces, each piece containing approximately the same number of eggs. One piece of polyethylene was floated in the test solution, and the other in spring water as a control. Hatching occurs in 168 h at 24/sup 0/C. Toxicity of the test solution may be scored on the percentage of eggs hatching, the number of abnormal larvae produced, and larval survival.