Putrefaction was pronounced during the second and third days after poisoning, and 
it seems likely that there may have been weight shrinkage as great as 5 or 10 per cent 
due to bacterial action, No corrections have been attempted for such losses. Large 
representative samples were preserved for the Survey collections and for subsequent 
examination, Scales from several kinds were taken for age determination, 
As many of the fry of the year as could be gathered up were preserved, These 
amounted to about one pound, All other fish were buried as fast as the observations 
on them were completed, 
The four most abundant species (by weight) in Fork Lake were the black bullhead, 
redmouth buffalo, carp and golden shiner, Only 32 of the 3,520 black bullheads were 
large enough to be caught and dressed, Redmouth buffalo almost never take the hook, 
Carp bite more readily but few people are interested in fishing for them, The golden 
shiner is a large minnow but 18 not considered edible nor sought for by anglers. The 
numbers and weights of fish of legal size of those kinds which take the hook readily 
are given in tablé 6, These edible hook-and-liné fish weighed 36.7 pounds, less than 
5 per cent of the total weight of all fish. 
TABLE 6,—~HOOK-AND-—LINE FISH OF EDIBLE SIZES 
Legal 
Length, Weight, 
Inches Number Pounds 
Largemouth bass 
White crappie . 
Warmouth bass . 
beh] 4. os wads 
Green sunfish , 
Channel catfish 
Black bullhead, 
lanka ble 
Fle © © e@ ee @ @ 
é 
* Arbitrary sizes chosen as the minimum for table use, 
LIMNOLOGICAL OBSERVATIONS 
At the time of the fish census the lake had a surface temperature between 80 and 
90 degrees F. The water was thermally stratified and had a temperature approximately 
70 degrees F. near the bottom, Later (August 10), during a period of very warm weather, 
temperatures and dissolved oxygen concentrations near the center of the lake were found 
as shown in table 7, 
TABLE '7,-—TEMPERATURES AND DISSOLVED OXYGEN 
CONCENTRATIONS, AUGUST 10, 1938 
Temperature, Dissolved Oxygen, 
Dégrees F, Parts per Million 
While the deeper samples showéd depletion of oxygen, there was still sufficient 
for most of the kinds of fish found in Illinois lakes, Although the lake is protected 
11 
