DISTRIBUTIONAL VARIATIONS WITHIN THE SAME STREAM

An analysis of faunal variations in different parts of the same stream system was made for Big Caney River and Grouse Creek. Collecting was more extensive in these streams, and sampling was done over a wider range of habitat, than in the Arkansas and Walnut rivers.

The fish taken in the first five seine hauls at each station were counted and the number of each species was recorded as a percentage of the total number of fish taken. These percentages were calculated for the main stream and for each tributary in an attempt to discern possible intra-stream faunal patterns. In Table 6 lower, middle, and upper segments of each stream have been segregated and the average of all stations within each segment is shown.

The results are subject to several sources of error, some of which are discussed below:

(1) Seining techniques could not be entirely standardized. One station might present a series of long narrow riffles and narrow, shallow pools in which only a small seine could be used effectively; another station might consist of a large, deep, isolated pool in which a larger seine was needed for effective sampling. In practice, the five seine hauls were made with any of several seines ranging from ten to twenty feet in length.

(2) Seines are species-selective, due partly to the preference of certain fishes for special habitat niches. Fishes that are often found under stones or in weedy pools require special collecting techniques and frequently were not represented in the initial five hauls. If work subsequent to the first five hauls indicated that such fish were a prominent part of the fauna at a particular station, these results were considered before percentages were calculated.

(3) Temporal variations occur in populations at the same station. There were both seasonal and diurnal differences in relative numbers of species taken in these collections. This was noted especially at station C-5 where collecting was done both at night and by day. Spawning by certain species during the course of the study complicated estimates of their relative abundance.

(4) In tabulating percentages of fishes obtained an arbitrary element is often unavoidable in deciding whether a station, especially a station on a tributary, should be considered as part of the lower, middle, or upper segment of a river system.

Despite these disadvantages it is felt that table 6 has factual basis permitting some reliable interpretation.

Table 6.—Relative Abundance in Per Cent of Fishes in Collections From Three Stream Segments.

Big Caney RiverGrouse Creek

LowerMiddleUpperLowerMiddleUpper

L. osseus .7 .5 .6 .02

D. cepedianum .3 .02

Carpiodes carpio .06 1.0

I. bubalus .6 .45 1.4

I. cyprinella .1

I. niger .01

M. erythrurum .2 1.1 1.0 .03 .5 1.1

M. melanops .1 .01 .1

Cyprinus carpio .7 1.3 .2

C. anomalum .6 5.9 18.0 .1

N. boops .6 .6 5.1 1.3

N. buchanani .01

N. camurus 6.4 5.5 .4

N. lutrensis 8.8 1.0 .5 6.4 11.4 15.2

N. percobromus 1.1

N. rubellus .4 1.4 3.9

N. umbratilis 17.6 28.3 15.4 2.5 3.9 5.5

N. volucellus .3 .4 .3

P. mirabilis .3

P. notatus 3.5 5.7 13.0 .9 6.6

P. vigilax .8

P. promelas 2.9

P. tenellus .7 .5 .01

G. affinis 14.6 .4 .4 20.8 10.2 1.0

F. notatus .1 6.6 17.2 1.4

I. melas .9 2.2 2.4 5.6 2.3 18.0

I. natalis .5 .5 .8

P. olivaris .01 .01

I. punctatus .3 .4

E. spectabile 1.9 4.9 18.0 .4 .3 .3

P. copelandi .8 .1 .01

P. phoxocephala .1 .1

P. caprodes .4 .6 .2 .2 .2 .4

M. salmoides .06 1.1 .3

M. punctulatus .5 1.7 .4

P. annularis 3.9 .8 2.9 4.2 .3

L. cyanellus 3.4 .8 6.6 5.2 1.8 30.5

L. humilis 10.6 13.1 1.8 31.4 17.7 14.8

L. megalotis 12.4 22.3 12.0 3.6 14.0 1.7

L. macrochirus .3 .2 1.3

A. grunniens .1

L. sicculus 7.1 1.6 .4 7.7 10.2

Big Caney River

The "lower segment" of Big Caney River is immediately upstream from Hulah Reservoir, and is not the lowermost portion of the entire river basin, but merely the lower part of the river in the area studied. A conspicuous characteristic of the lower segment was the general restriction of the deep-bodied suckers and the carp to this part of the stream. Other fishes that were most common in the lower section were Pimephales vigilax, Percina phoxocephala, Gambusia affinis, and Aplodinotus grunniens. Labidesthes sicculus and Lepisosteus osseus ranged into the middle section of the stream, but were present in larger numbers downstream. Ictalurus punctatus, Pomoxis annularis, and Lepomis macrochirus were taken chiefly in downstream habitats; however, stocking has confused the distributional pattern of these species. Notropis lutrensis, although found throughout the system, progressively declined in numbers taken in the middle and upper sections. Approximately 18 species were usually taken in downstream collections.

No species were found exclusively in the middle section of the Big Caney system. Micropterus punctulatus, Notropis umbratilis, and Lepomis megalotis tended to be most common in the middle section of the main stream. These three species were taken together at stations C-5, C-6, C-8, and C-10.

The upper section yielded no species that did not occur also in another section. Fishes most abundant in the upper section included: Campostoma anomalum, Etheostoma spectabile, Notropis boops, Notropis rubellus, Pimephales notatus, and Lepomis cyanellus. Ictalurus natalis also seemed more common upstream than in lower parts of the basin.

Campostoma anomalum was one of the most common fishes taken at many of the stations on small upland tributaries. In downstream collections its relative abundance was less, although it was often concentrated on riffles.

In the Big Caney system as a whole Notropis umbratilis was the most abundant species. Several species were present throughout the system in proportions varying, sometimes greatly, from station to station. Lepomis megalotis and Lepomis humilis were erratic in occurrence, and the numbers of Notropis camurus and Ictalurus melas varied without pattern.

Grouse Creek

The fauna of the main stream of Grouse Creek fluctuated more in number and kinds of fish from station to station than did the fauna of Big Caney River. Again, the deep-bodied suckers showed downstream proclivities. In addition, Notropis buchanani, Pimephales tenellus, Percina copelandi, Percina phoxocephala, Notropis percobromus and Pylodictis olivaris were taken only at the lowermost station (G-1). At stations G-2 and G-3 the creek is sluggish and often turbid, meandering between high mud banks in a flood plain. At these stations Fundulus notatus, Gambusia affinis, Labidesthes sicculus, Ictalurus melas, and Lepomis humilis were the most common fishes. Shiners (Notropis spp.) and Lepomis megalotis were rarely taken. Hall (1953:36) states that Gambusia affinis, Fundulus notatus, and Labidesthes sicculus are usually associated with overflow pools, oxbows, and vegetated backwaters.

Those fishes mentioned in the preceding paragraph remained common in the middle section of the stream. In addition Notropis lutrensis, Notropis umbratilis, and Lepomis megalotis were important members of the fauna.

In the uppermost section shiners (Notropis spp.) were common. In the few upstream stations that were still in good condition with clear flowing water, the fauna resembled that of the upstream stations on Big Caney River. Most upstream stations on Grouse Creek were located on highly intermittent streams that are treated below.