though the soft parts of the animals had been digested away. Although the results are not 

 strictly representative, it is possible to compare the stomach contents of the different 

 fish from month to month because these fish remained in the nets for similar lengths of 

 time. 



Two criteria can be used to express the degree of feeding: (1) the amount of food in 

 the stomachs and (2) the percentage of empty stomachs. These are shown in table 14. 

 Since the bass has a larger mouth than the bluegill and swallows larger animals which take 

 a longer time to digest, it feeds at irregular intervals and is represented by a greater 

 percentage of empty stomachs. 



TABLE 14.— FEEDING ACTIVITY OF 299 BASS AND 671 BLUBGILLS TAKEN 

 FROM FORK LAKE, 1939, AS DETERIUNED BY STOMACH ANALYSIS. 



Spawning activity in the bluegills, and warm water resulting in a rapid rate of di- 

 gestion, may accovmt for a high percentage of empty stomachs found in these fish during 

 summer. About the same percentages of empty bass stomachs were found throughout the 

 growing season. 



In tables 15 and 16, important food items are shown as percentages of total weight 

 of stomach contents of the 1938 broods of largemouth bass and bluegills. During some 

 months there are indications of food competition; dioring others the important foods overlap 

 but little. 



This study of stomach contents suggests the following conclusions: 



1. Crayfish of the year must have been exterminated early because none were found in 

 bass stomachs after July. 



2. The higher percentage of plants eaten by old bluegills may mean that the old fish 

 were less active than the yearling fish in seeking animal foods and that they 

 used plants as stuffing. 



3. Bluegills and bass compete for insects wher fish are not available for the bass; 

 however, bass eat more flying insects, and bluegills more immature aquatic Insects. 



4. The poor growth of bass during 1939 was due to a shortage of fish in their diet, 



5. The most important groups of aquatic insects used for food in Fork Lake are the 

 Diptera, Odonata and Hemiptera. Of these, the Dlptera are consistently Important 

 as bluegill food and the Odonata as bass food. 



HOOK-AND-LINE CATCH IN RELATION TO WATER TRANSPARENCY 



Hook-and-line fishing began in March and ended in September, with a total of 55.2 

 man-hours. Fishing in Fork Lake was considered ordinarily good, although most of the bass 

 caught were under legal length. Table 17 describes this hook-and-llne catch. 



The catch per man-hour varied from zero to 8.0, and the average catch for all dates 

 combined was 4.37 fish per man-hour. 



19 



