Comparative sensitivity of a tropical mysid Metamysidopsis insularis and the temperate species Americamysis bahia to six toxicants

The sensitivity of the tropical mysid, Metamysidopsis insularis relative to that of the sub-tropical North American mysid, Americamysis bahia was determined by comparing their acute toxicity to six toxicants. The 96 h LC50 values for M. insularis ranged from 0.03 mg L-1 (cadmium (Cd) chloride) to 466 mg L-1 (potassium chloride (KCL) whereas those for A. bahia ranged from 0.1 mg L-1 for Cd chloride to 501 mg L-1 for KCl. The interspecies correlation indicated that the mean acute toxicities for M. insularis showed a high positive correlation with A. bahia (r2 = 1.0). Data suggest there were no significant differences between acute toxic responses of the two species to these toxicants. The results suggest that though M. insularis and A. bahia occur in different climatic zones, the difference in relative sensitivities of the two species due to temperature preferenda may be negligible. Consequently, M. insularis may be considered suitable tropical test species for use in toxicity testing in Trinidad and Tobago.