Fish Acute Toxicity

Ecotoxicity testing determines hazard or risk presented to fish and other species by substances that may enter the environment. The ICCVAM Ecotoxicology Workgroup has published a summary (Ceger et al. 2022) of selected U.S. federal agency needs for ecotoxicity testing, emerging technologies for evaluating ecotoxicity and environmental safety, and the potential applicability of those technologies for regulatory testing. 

Fish acute toxicity tests are used to assess potential risk to fish species and for other ecological regulatory needs associated with surface water contaminants. To meet EPA data requirements the test is typically conducted in three different fish species: a cold-water freshwater species, a warm-water freshwater species, and a marine/estuarine species. The ICCVAM Ecotoxicology Workgroup is evaluating ecotoxicology methods involving animal testing and what alternatives exist to replace, reduce, or refine animal use in the acute fish toxicity assay. NICEATM is also working with EPA and other partners to explore reducing animal use for fish acute toxicity testing.

Curation and Analysis of Testing Data

As noted above, fish acute toxicity testing is conducted using three species per chemical. Thus, each chemical tested can potentially require up to 260 fish. NICEATM and EPA conducted a retrospective evaluation of existing data to explore the potential for relying on fewer fish species tests to support a protective ecological risk assessment (Ceger et al. 2023). The results support potentially using fewer than three fish species to conduct ecological risk assessments for the registration of conventional pesticides. Extracted data will be submitted to EPA’s Toxicological Reference Database.

Acute fish toxicity data set (from Figure 1, Ceger et al. 2023)