Determining the suitability of Ceriodaphnia rigaudii as a toxicity test species.

The selection criteria for toxicity test species though well documented, does not provide a clear approach for establishing the suitability of a species for toxicity testing. This study looks at an approach used for establishing C. rigaudii as a suitable freshwater toxicity test species for regulatory testing in Trinidad and Tobago. A comparison was made between the life cycle, toxicological responses and sensitivity of C. rigaudii and D. magna. The results showed that C. rigaudii (0.45mm) was significantly smaller in size, had a shorter life cycle, matured faster and was more sensitive to toxicants than the temperate cladoceran species, D. magna. This study was useful in defining a stepwise approach to help establish C. rigaudii as an indigenous tropical toxicity test species in Trinidad.