Because of severe, protracted drought, most of the streams studied had
ceased to flow by the close of the survey period. However, the duration
of intermittency varied greatly in different streams, as did its effect
in terms of the number and sizes of residual pools, water temperatures,
pollution, and turbidity. Crab Creek, Beaver Creek, and a small unnamed
tributary of Grouse Creek were severely affected by intermittency. Their
faunas are discussed below.
In Crab Creek six collections were made from points near the mouth to
the uppermost pool in which water was found. Pools near the mouth were
as large as thirty feet in width and ninety feet in length, while those
that were uppermost were shallow puddles averaging ten feet in length
and five feet in width. The uppermost station was situated in bluestem
pasture without benefit of shade from trees.
The species taken and their relative abundances based on five seine
hauls at each station are shown in Table 7. At the uppermost pool (G-17)
only small green sunfish were found. At G-16, next downstream, this
species was joined by large numbers of black bullheads and a few redfin
shiners and red shiners. G-13 was similar to G-16, but two additional
species occurred there. G-12 was a clear, deep pool much larger than any
at the stations upstream. Here, seven species were added to the fauna,
and the percentages of _Ictalurus melas_ and _Lepomis cyanellus_ were
much less. At G-10 _Fundulus notatus_, _Labidesthes sicculus_, and
_Minytrema melanops_ appeared. Nevertheless, fewer species (10) were
captured here than at station G-12 upstream.