J. M. Lawrence

The Effects Of Heated Water On Warmwater Fish In Earthen Raceways

Two-year studies were conducted in 3 earthen raceways (160 m x 6 m x 2 m). One raceway was maintained at ambient water temperature, I had a heated floating plume over 60% of the surface, and 1 was maintained at near heated water discharge temperature. Average water temperatures ranging up to 36.7 C were not lethal for any fish species tested. With the possible exception of threadfin shad (Dorosoma petenense) 110 difference in long-term survival of any species was detected, but when the entire population was considered as a whole, survival of fishes confined to the highest temperatures was...

Year
1977

The Status Of Diquat And Paraquat As Aquatic Herbicides

The chemical and physical properties and phytocidal activity of diquat (1:1'-ethylene- 2 :2'-bipyridylium cation) and paraquat (1 :l'-dimethyl-4 :4'-bipyridylium cation) are discussed. Data are presented on the evaluation of herbicidal activity of the various salts of these 2 chemicals under controlled laboratory conditions, in plastic pools, and in earthen ponds. Research indicates that a majority of common submersed and many emergent aquatic weeds may be killed by concentrations of 0.2 to 0.5 ppm cation of these 2 chemicals. Fish toxicity studies indicate a threshold toxic concentration...

Year
1962