Goldeye (Hiodon alosoides) and Mooneye (Hiodon tergisus) 



These two species are the only members of their genus and of their 

 family, Hiodontidae. Both species are called mooneye by fishermen, and 

 both are considered commercial species (Illinois Department of Conserva- 

 tion, 1974). Adults are up to 15 in. in length and will take lures or 

 bait and furnish good sport for anglers. 



Mooneye were taken infrequently and only from the Alton Pool until 

 1974, when one was taken from upper Peoria Pool at mile 215 (Table 8). 

 Goldeye (Table 9) were taken more frequently and ranged farther upstream 

 than their relative, the mooneye. However, in 1974 only two goldeye 

 were taken, all from one station at mile 261 in Marseilles Pool. 



Mooneye were once caught fairly regularly in the Ohio and 

 Mississippi Rivers, but mooneye populations declined prior to 1908 

 (Forbes and Richardson, 1908) . Mooneye and goldeye have unusually large 

 eyes, and the "eye shine" is caused by a reflective layer in the retina 

 which may assist vision at night or in dim light in deep water. Since 

 both species appear to be sight predators, they have probably been ad- 

 versely affected by increasing turbidity. Trautman (1957) thought that 

 goldeye were more tolerant of turbid water than mooneye. Both species 

 inhabit the swift, open water of large rivers, and spawn in flowing water 

 over rocky and gravelly bottoms. High-water levels and swift currents in 

 the years 1972-1973 may have been temporarily beneficial to mooneye and 

 goldeye. The impounding of water behind navigation dams with the at- 

 tendent reduction in current and increasing siltation has probably con- 

 tributed to the reduction in mooneye and goldeye populations. 

 Grass pickerel (Esox americanus vermiculatus) 



Grass pickerel were taken rarely by electrof ishing from the Illinois 

 River, and were never very abundant. 

 Northern pike (Esox lucius) 



Northern pike were taken by sport fishermen in the river below 

 Marseilles Dam in 1973 and were netted in Lake Chautauqua in 1973 (river 

 mile 126.0), but have never been taken by electrof ishing. Northern pike 

 were common in the river before 1908 (Starrett, 1972). In the 1870's 



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