carp, river carpsucker, and white crappie. The 

 remaining major species, not in order of abun- 

 dance, were shovelnose sturgeon, shortnose gar, 

 smallmouth buffalo, channel catfisn, black 

 crappie, sauger, and freshwater drum . The 

 following species disappeared or were rare in 

 the reservoir in 1962: pallid sturgeon, paddlefish, 

 longnose gar, rainbow trout, blue sucker, white 

 sucker, blue catfish, stonecat, black bullhead, 

 northern pike, burbot, green sunfish, and orange - 

 spotted sunfish. 



It is assumed that the number of each 

 species of fish captured each year, based on the 

 amount of fishing effort expended, was related 

 to their actual abundance. Only those sizes of 

 fish vulnerable to capture by the fishing gear 

 were included . It is realized that both gill nets 

 and frame nets were selective to both size and 

 species of fish captured and that abundance esti- 

 mates derived from their use must be viewed 

 with caution. Validity of tlie method used to 

 estimate relative species abundance is dependent 

 upon similar fish behavior within and between 

 years. Behavior is influenced by changes in the 

 reservoir environment such as water level fluctu- 

 ation, turbidity, wind, and available food. De- 

 spite these limitations, and because the annual 

 catch data were obtained in a reasonably con- 

 sistant manner, they constitute a useful index of 

 species abundance. 



Frame nets and gill nets were not equally 

 efficient in fish capture (tables 3 and 4) and it 

 was necessary to adjust the fishing effort of 

 these gears to a standard unit. Relative annual 

 abundance of each species was determined by 

 comparison of the average catch per unit of 

 effort of each type of fishing gear. From this 

 comparison, the relative efficiency of the frame 

 net to the gill net in the capture of the various 

 species was determined. The number of gill 

 net sets was multiplied by an efficiency factor 

 to obtain total effort in frame net units (adjusted 

 effort). Total catch was divided by adjusted 

 effort to obtain the adjusted catch per unit of 

 effort in each year. Adjusted catch per unit of 

 effort in each year was compared with that in 

 1956, and relative abundance in relation to 1956 

 was determined. This procedure was followed 

 to determine the relative annual abundance of 



each major species, and is, illustrated for the 

 river carpsucker in table 5. 



Apparent abundance of most fishes declined 

 between 1956 and 1962 (table 6). Marked de- 

 creases were suggested for shovelnose sturgeon, 

 carp, and black crappie. Both white crappie 

 and black crappie experienced wide fluctuations 

 in abundance and in 1962 were at a relatively 

 low level. Black crappie predominated over 

 white crappie in 1957 but this relationship was 

 gradually reversed in the period between 1958 

 and 1962. The abundance of shortnose gar, 

 smallmouth buffalo, and river carpsucker re- 

 mained rather stable after 1957. Sauger a - 

 bundance has increased since the early years 

 of impoundment, and freshwater drum abundance 

 increased in 1962 compared with that of previous 

 years . 



Shoreline seining was conducted to determine 

 the relative abundance of fishes vulnerable to 

 capture by this gear (table 7). The silvery 

 minnow, which was most abundant following 

 formation of the reservoir, declined to a low 

 level and the emerald shiner became the dominant 

 cyprinid species. Gizzard shad, relatively rare 

 prior to impoundment, became the most abundant 

 forage species. Similar changes in shad a- 

 bundance were noted by Martin and Campbell 

 (1953) in Clearwater Lake . 



LIFE-HISTORY OBSERVATIONS 



General life -history studies were con- 

 ducted on fishes collected, to determine (1) age 

 and rate of growth, (2) age -class composition, 

 (3) habitat preference, (4) period of spawning, 

 and (5) reproduction success. All fish lengths 

 reported are total lengths in inches . Scaled 

 fishes were aged by conventional methods 

 (Lagler, 1952). Aging of nonscaled fish, which 

 was begun in 1962 , was from study of spine or 

 fin ray cross -sections and branchiostegals . 

 Average calculated lengths at each annulus were 

 determined by assuming a straight-line relation. 

 Habitat preference was determined from location 

 of fish capture within the reservoir . Period of 

 spawning was determined from gross obser- 

 vation of gonads . Shoreline seining (table 7) 

 was used to indicate reproductive success. 



