Improving Fish Welfare by Seeking Alternative Methods in Toxicity Testing

Chemical and effluent toxicity is frequently evaluated using a test developed by the US EPA called the larval growth and survival (LGS) test, in which the survival and growth of larval fish exposed to chemicals or effluents for a 7 day period is evaluated. In an effort to improve animal welfare, the fish embryo toxicity (FET) test has been proposed as a replacement for the LGS test. With this in mind, our lab has worked to: 1) determine whether a 5-day fathead minnow FET test a viable replacement for a 7-day fathead minnow LGS test by comparing the sensitivity of these test types, 2) identify sub-lethal endpoints that improve the sensitivity and utility of the fathead minnow FET test. Thus far, our work in this area has shown that the FET test offers comparable performance to the LGS test for some, but not all chemicals tested. However, we have also shown that reduced length and increased pericardial area, two commonly observed effects following exposures to a variety of chemicals, are robust predictors of delayed mortality and that their inclusion as apical endpoints dramatically improves the sensitivity of the FET test. Publications related to this work can be found here and here.

Our lab has also just begun to explore the use of fish embryos and invertebrates, specifically opossum shrimp, as replacements for fish larvae utilized to evaluate the toxicity of chemicals and effluents released into marine systems. Currently, sheepshead minnow and inland silverside LGS tests are utilized to evaluate acute toxicity in marine receiving environments and our work seeks to compare the performance of these tests to a sheepshead minnow FET test, an inland silverside FET test, and an opossum shrimp survival and growth test.