Exploring Alternatives for Marine Toxicity Testing: Initial Evaluation of Fish Embryo and Mysid Tests

Area of Science:

• Environmental Toxicology
• Marine Ecotoxicology
• Animal Alternative Testing

Background:

• Current regulations mandate standardized toxicity testing, often using fish.
• Legislation promotes the 3Rs (replacement, reduction, refinement) for animal testing.
• Limited development exists for marine toxicity testing alternatives compared to freshwater.

Purpose of the Study:

• To compare the sensitivity of marine alternative toxicity tests (fish embryo toxicity, mysid shrimp) with standardized fish tests.
• To characterize marine fish embryo development for improved FET test application.
• To assess the efficacy of 3,4-dichloroaniline (DCA) as a reference toxicant.

Main Methods:

• Applied fish embryo toxicity (FET) tests to sheepshead minnow and inland silverside embryos.
• Conducted mysid shrimp survival and growth tests.
• Compared sensitivities of FET, mysid shrimp, and standardized fish tests using DCA.
• Characterized marine fish ontogeny for embryo staging.

Main Results:

• Standardized fish tests and mysid shrimp tests demonstrated comparable sensitivity.
• Marine FET tests were less sensitive than fish and mysid shrimp tests.
• Including sublethal endpoints (hatchability, pericardial edema) in marine FETs enhanced their sensitivity.

Conclusions:

• Mysid shrimp tests are viable alternatives comparable to fish tests for marine toxicity assessment.
• Marine FET tests require refinement, such as incorporating sublethal endpoints, to match the sensitivity of traditional methods.
• Further development of alternative marine toxicity testing strategies is crucial for implementing the 3Rs.