Changes in the Fauna at the Upper Neosho Station, 1957 Through 1959.
The following discussion is based principally on collections made with rotenone in 1957, 1958 and 1959 (Table 12). Other supplementary data aid in understanding the changes that occurred after the resumption of normal flow at the upper Neosho station.
The population in 1957 was strongly dominated by black bullhead and young-of-the-year channel catfish. Other common species were long-eared sunfish, red shiner, yellow bullhead, orange-spotted sunfish and green sunfish. This fauna, with the exception of young-of-the-year individuals, was a fauna produced during the years of drought. Deacon and Metcalf (1961:318-321) found a similar fauna in streams of the Wakarusa River Basin that had been seriously affected by drought.
The black bullheads taken in 1957 were predominately yearlings. It is likely that by 1956 the total fish population in the upper Neosho had been decimated by drought. The ponded conditions prevalent in that year were conducive to production and survival of young black bullheads. Fig. 3 shows that this dominant 1956 year-class reached an average length of approximately 6.5 inches by August, 1959.
Reproduction by black bullheads was limited in 1957, 1958, and 1959, and slight reduction in relative abundance occurred from 1957 to 1958. The relative abundance in 1959 remained nearly stable. If stream-flow remains essentially continuous for the next few years, the number of black bullheads probably will decline as individuals of the 1956 year-class reach the end of their life-span.
Reference has been made to the large hatch of channel catfish in 1957, in a discussion of that species. Conditions for survival of young channel catfish at the upper Neosho station in 1957 were good because there was continuous flow over many gravel-rubble riffles, which were largely unoccupied by other fish, in the spring and summer of 1957.
Table 12. Percentage-composition of the Fish-fauna at the Upper Neosho Station in 1957, 1958 and 1959, as Computed from Collections Obtained by Using Rotenone.
| Species | 1957 | 1958 | 1959 |
|---|---|---|---|
| Big-mouthed Buffalo............... | ........ | T[D] | T |
| Small-mouthed Buffalo............. | ........ | ....... | T |
| River Carpsucker.................. | T | 0.8 | 1.8 |
| Golden Redhorse................... | T | 3.0 | 5.7 |
| Creek Chub........................ | ........ | T | 0.8 |
| Red-finned Shiner................. | 1.3 | 3.0 | 0.8 |
| Red Shiner........................ | 6.5 | 13.1 | 12.1 |
| Ghost Shiner...................... | T | T | ........ |
| Blunt-nosed Minnow................ | T | T | T |
| Fat-headed Minnow................. | T | T | 1.4 |
| Stoneroller....................... | 0.8 | 1.5 | 3.5 |
| Black Bullhead.................... | 40.8 | 30.5 | 32.0 |
| Yellow Bullhead................... | 5.3 | 8.8 | 2.5 |
| Channel Catfish................... | 28.4 | 15.5 | 18.5 |
| Flathead.......................... | T | T | T |
| Stonecat.......................... | T | T | 1.4 |
| Spotted Bass...................... | T | T | 0.8 |
| Largemouth........................ | T | T | T |
| Green Sunfish..................... | 3.1 | 6.8 | 6.4 |
| Long-eared Sunfish................ | 8.8 | 3.7 | 1.9 |
| Orange-spotted Sunfish............ | 3.1 | 8.9 | 2.5 |
| Bluegill.......................... | T | T | T |
| White Crappie..................... | T | ....... | T |
| Logperch......................... | T | 2.1 | 0.8 |
| Slender-headed Darter............. | 0.6 | 0.6 | 3.1 |
| Orange-throated Darter............ | ........ | T | 2.5 |
| Total number of fish.............. | 786 | 965 | 513 |
| Size of sample-area in acre-feet.. | .002 | .33 | .33 |
Channel catfish also showed a slight decline in relative abundance after 1957, resulting from mortality in the 1957 year-class. With continuous flow, channel catfish will probably remain abundant, although annual reproductive success probably will be less than in 1957.
The big-mouthed buffalo, small-mouthed buffalo, creek chub and orange-throated darter were not taken in 1957, but appeared in collections in 1958. The river carpsucker, golden redhorse, red shiner, fat-headed minnow, stoneroller, stonecat, and slender-headed darter also increased in abundance between 1957 and 1959. The increased abundance of all these species in 1958 and 1959 resulted in a more diversified fauna, with lesser predominance by any single species, than in 1957 (Table 12); this change is related to the increased, permanent flow in 1958 and 1959.