December, 1958 



Bunn'I'Tt: Aquatic Hioi.ogy 



173 



zard shad, and stunted bluegills ; all day, 

 local sportsmen slipped throujj;h the un- 

 derbrush to spy on the "fish killers," but, 

 seeing few, or no, dead useful hook-and- 

 line Hsh, they stayed to help us collect 

 the outsized carp and buffalo. 



Throujj;h the able assistance of Sam A. 

 Parr, at that time Investigator for the 

 Department of Conservation for Macon 

 County, we were able to census 22 arti- 

 ficial lakes and ponds in central and 

 southern Illinois. One of these ponds 

 was Fork Lake, owned by Paul S. Smith 

 (formerly Chief Inspector with the De- 

 partment of Conservation), who gave us 

 carte blanche use of the pond, 'i'hese 

 censuses, and the studies of the fish popu- 

 lations that replaced those poisoned in 

 these ponds, led to the publication of three 

 reports on lake management (Thompson 

 & Bennett 193%, 1939^*, and Bennett, 

 Thompson, & Parr 1940) and two articles 

 of the Bulletin, "Management of Small 

 Artificial Lakes" (Bennett 1943) and 

 "The Bass-Bluegill Combination in a 

 Small Artificial Lake" (Bennett 1948). 



Censuses of the ponds, most of which 

 were poor fishing waters, brought out the 

 fact that overpopulation and stunting 

 and/or large numbers of fish of undesir- 

 able species, rather than a lack of fish, 

 were the causes of poor fishing. In fact, 

 one of the poorest ponds for fishing was 

 found to contain 1,145 pounds of Hsh per 

 acre. At Fork Lake ("The Bass-Bluegill 

 Combination in a Small Artificial Lake"), 

 we attempted to crop heavily the large- 

 mouth bass and bluegills in this 1.4-acre 

 pond; we used six fyke nets of 1 -inch- 

 mesh, set with leads to completely block 

 off the pond into sections. When these 

 nets were fished for 10 days each month 

 from March to November of each year 

 for 3 years, we discovered that we could 

 not crop the bass because they refused to 

 enter the nets, and the constant cropping 

 of bluegills contributed to the well-being 

 of both species. This discovery led to the 

 belief that anglers had nothing to fear 

 from commercial fishing operations. 



In July of 1938 Hansen was given 

 charge of the scale collections for study- 

 ing age and growth of fishes and the task 

 of investigating the fish populations of 

 water supply reservoirs where fishing was 

 an important secondary function to water 



supply. At that time he was operating 

 f\ke nets at Lake Decatur and in other 

 waters in order to gather material for a 

 life historv study of the white crappie 

 (Hansen 1951). 



In the late 1930's and the early 1940's 

 federal agencies were engaged in con- 

 struction projects under various work 

 programs. The Natural Histor\- Survey 

 was to benefit from these programs 

 through the construction of a laboratory 

 located on the Chautauqua National 

 Wildlife Refuge, near Havana, and a 

 laboratory and artificial lake in Fox 

 Ridge State Park, near Charleston. The 

 Havana laboratory, completed in early 

 1940, became the headquarters for water- 

 fowl and fishery research on the Illinois 

 and Mississippi rivers. The laboratory 

 and lake in Fox Ridge State Park were 

 completed in 1941 and became a center for 

 studies on largemouth bass management. 



About the same time the U. S. Forest 

 Service constructed two lakes in the 

 Shawnee National Forest in the southern 

 part of Illinois. These were Pounds Hol- 

 low Lake, near Gibsonia, and Lake Glen- 

 dale, near Dixon Springs ; the latter has 

 been used by the Natural History Sur- 

 vey as a study area since it was first 

 stocked in 1940. Lake Glendale is located 

 in a region of low soil fertility and is 

 fairly typical of impoundments in forested 

 lands. Hansen has found that the lake 

 produces excessive populations of both 

 bass and bluegills, and that fishing may 

 be improved at intervals by the removal 

 of part of the population of both of these 

 species. 



In 1942 Thompson and Hansen made 

 a fish survey of the Illinois River from 

 Channahon to the river mouth at Graf- 

 ton. About 34,000 fish were studied, 

 most of which were caught in hoop or 

 fyke nets. Many of the carp in the upper 

 part of the river (particularly at all sta- 

 tions above Henry) showed the knothead 

 abnormality which was an indication of 

 gross pollution. At Channahon 94.8 per 

 cent of the catch was composed of 

 "rough" fish, most of them carp or gold- 

 fish. In contrast, at the Creve Coeur 

 station below Peoria, 88.4 per cent of the 

 fish taken were "fine" fish (most of them 

 white crappies or black crappies) and 

 onl\' 6.0 per cent were "rough" fish. 



