Toxicity of the herbicides 2,4-D, DEF, propanil and trifluralin to the Dungeness crab, Cancer magister.

Lethal and sublethal responses to the herbicides 2,4-D, DEF, propanil, and trifluralin of various life history stages of the Dungeness crab, Cancer magister, were examined to estimate maximum acceptable toxicant concentrations (MATC) of each compound for this species. Zoeae were found, in long term tests, to be the most sensitive stage. Based on the experiments with this stage, MATCs were concluded to be greater than 0.95, less than 6.9 microgram/L for DEF, greater than or equal to 26, less than 220 microgram/L for trifluralin, greater than or equal to 1,700 microgram/L for propanil, and less than 1,000 microgram/L for the free acid form of 2,4-D.