ABSTRACT
Eurasian watermilfoil will grow in clear waters up to 9 ft deep at mean low tide in the Chesapeake Bay and its tributaries, and exists in fresh to brackish waters of up to 15% salinity. Extensive experiments showed that 2,4-D butyl ethylester at recommended rates in Chesapeake Bay waters had no primary lethal effects on oysters, soft-shelled clams, blue crabs, Callinectes sapidus, and various species of test fish. Herbicide use in waters yielding animal food for human consumption poses two immediate considerations — toxicity to organisms in the treated areas, and herbicide residues occurring in edible fauna. Herbicide application was delayed a week to allow time for bioassay animals to adjust to their new environment. Before herbicide treatment on July 5, 1966, each tray and cage of test animals was examined for mortality resulting from natural causes or from mechanical injury incurred during dredging.
