142 Theories and Techniques of Management 



powder ( calcium hypochlorite ) to give several parts per million * of free 

 chlorine, or rotenone ( as 5 per cent cube powder ) or emulsifiable rotenone 

 (2 to 5 per cent) to give 1 ppm or more. It is desirable to use a fish poison 

 that disappears rapidly so that fish can be restocked widiin a few days. 



After the fish and water have been removed from a lake basin and the 

 water pockets and channels treated, the outlet valve can be closed so that 

 water will collect in the basin. However, the basin may be allowed to 

 dry for several months before reimpoundment is begun, if the fish to be 

 restocked can be held for this length of time. 



Population Removal by Rotenone Treatment, The use of rotenone con- 

 taining plants as an aid in catching fishes is common to the native in- 

 habitants of many widely separated tropical and subtropical countries. 

 Leonard ''^ and Krumholz ^^ described the catching of fish by natives of 

 Australia, Oceania, and southern Asia by the use of tuba, the local name 

 for a substance (rotenone) originating from plants (Genus Derris) native 

 to those regions. In tropical South America, the same substance, extracted 

 from plants belonging to several genera such as Lonchocarpus and 

 Trephosia, is known as cube, timbo, barbasco, and by other names, de- 

 pending upon the plant source and locality. Both Dr. Leonard and Dr. 

 Krumholz recount descriptions of tuba fishing parties from the writings 

 of early explorers in Sumatra, Sarawak, and Brazil. 



The insecticidal properties of rotenone are well known and for many 

 years there has been a large importation of rotenone-bearing plants into 

 the United States. Probably Professor Eigenmann was the first to use 

 native fishing methods with rotenone for collecting specimens of fishes in 

 South America. Dr. Carl L. Hubbs used powdered derris root with 5 

 per cent rotenone content for collecting fish in Guatemala in 1934. 



Rotenone was first used in fisheries management in the United States 

 in 1934 when Milton B. Trautman at the suggestion of Dr. Hubbs at- 

 tempted to eliminate goldfish from two small ponds on the W. O. Briggs 

 estate near Birmingham, Michigan. The attempt was not entirely success- 

 ful because the dosage was too light. 



In September, 1934, Michigan fisheries biologists attempted to eliminate 

 a population of stunted yellow perch from a 4.3-acre lake in Otsego 

 County, Michigan.-^ After 1937 the technique of killing fish witli rotenone 

 spread rapidly to other states. In 1938, biologists with the Illinois Natural 

 History Survey censused 6 ponds using rotenone treatment.^ 



Leonard's laboratory studies of the toxicity of rotenone to fishes in- 



* Parts per million is promulgated on a weight basis, i.e., one pound of a chemical 

 added to a million pounds of water equals one part per million. This is not too difficult 

 to visualize if one will remember that an acre of fresh water (43,560 square feet), one 

 foot deep, will weigh about 2.7 million pounds. Thus, 2.7 pounds of a chemical applied 

 to one acre of water, one foot deep ( one acre-foot ) , will give a dosage of one part per 

 milHon (ppm). 



