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.

Table 7.—Percentages of Fishes Taken on Crab Creek.

Table 8.—Fish Taken in Nine Pools on Upper Beaver Creek (Progressing From Downstream to Upstream).

A series of collections similar to that on Crab Creek was carried out along 1½ miles of Beaver Creek on July 22, 1956. Nine pools were sampled (Table 8) of which number nine was the uppermost point where water was found (except for farm ponds). Mainly young of Lepomis cyanellus and Ictalurus melas were found in the uppermost stations, as on Crab Creek. Only adults of Notropis lutrensis and Notropis umbratilis were taken.

In another small intermittent tributary of Grouse Creek two collections (G-14 and G-15) were made. One was from several isolated pools near the source of the creek and the other was 1½ miles upstream from the mouth. The two stations were approximately four miles apart. Table 9 indicates approximate percentages of fish taken in five seine hauls at these stations.

Table 9.—Fishes Taken in a Tributary of Grouse Creek.

At two other stations, only Lepomis cyanellus was found. One of these stations consisted of several small spring-fed pools in a dry arroyo tributary to Little Beaver Creek. Around these small "oases" rushes and smartweeds grew and blackbirds were nesting in the rushes. Although green sunfish up to eight inches in length were common in the shallow pools, no other species was found. The second station (C-17) on the East Fork Big Caney River is of special interest. The pool was isolated, had dimensions of about 25×25 feet, and had an average depth of 15 inches. The water was foul; cows had been fed fodder in a sheltered area above the pool during the preceding winter and the entire bottom was covered to a depth of 6 inches to 1 foot with a detritus of decomposing fodder, cattle feces, and leaves. The water became almost inky in consistency when the bottom was stirred and its odor was offensive. A thick gray-green bloom lay on the surface. This bloom was full of bubbles indicating gases rising from the bottom muds. One hundred fifty-three green sunfish, all less than 5 inches in length, were taken in one seine-haul at this station.