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<br />390
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<br />vol. 26, no.
<br />FIG. i.-The White River drainage, C entah County, Utah, showing locations of sampling sites
<br />(after Baumann et al., 1975).
<br />moving current and backwater areas. During normal and low flow conditions. a combination of
<br />seining and electrofishing also was used along a 300-m length of shoreline at each station. An
<br />electrofishing boat was used to sample all habitat suitable for shocking in the lower 39 kin of river
<br />in July and September 1978 and in the upper 67 km of river in Nlay and June 1979. All captured
<br />fish were identified to species and counted.
<br />November 1981 Lanigan and Berry-White River Fish Distribution 391
<br />TABLE I.-Total number of fish collected in three sections of the White River, Utah, 7978-79.1
<br />Percentage of total number captured is given in parentheses.
<br />River section
<br />Upper Middle Lower Total fish
<br />(station 1-4) (station5-II) (nation 12-15) e,ipwred
<br />RESULTS.-A total of 19,695 fish, divided among 12 species and two
<br />hybrids, was collected during the study (Table 1). The red shiner was the
<br />most abundant species (62.5% of the total number), followed by rouncitail
<br />chub (11..2%), flannelmouth sucker (8.6%D), speckled dace (8.4 0), fathead min-
<br />now (5.5%), carp (2.6%), and channel catfish (0.6%D). Bluehead sucker, black
<br />bullheads, green sunfish, brown trout, and Colorado squawfish each made
<br />up less than 0.5% of the total fish collected.
<br />Six adult squawfish were captured in the lower 19.6 km of the White
<br />River in 1978-three on 11 July and three on 28 September. Seven other
<br />squawfish were observed during, electrofishing in this section of the river but
<br />could not be captured. Two other squawfish were captured 55 km and 78 1
<br />km above the confluence of the Green River in 1979, on 5 May and 6 June,
<br />respectively. The eight captured fish ranged in length from 444 to 630 mm
<br />and in weight from 590 to 1250 g. The fish were probably 8 to 12 years old
<br />(Seethaler, 1978). Sex of the squawfish could not be determined by external
<br />features or by attempts to express sex products.
<br />Two fish believed to be hybrids of species endemic to the Colorado River
<br />Basin were collected. The first was collected 1 km above the confluence the Green River on 11 July 1978. The fish was morphologically similar to-=
<br />Gila elegans, but may have been an intergrade between G. elegans and G.
<br />cypha (Holden and Stalnaker, 1970). Measurements made on a picture of the
<br />specimen showed that the peduncle depth:head length ratio was less than
<br />that of a pure G. elegans (Minckley, 1973). Positive identification could not
<br />be made because of 1) the unresolved taxonomy of the two species (Holden
<br />and Stalnaker, 1970) and 2) the specimen was released. The specimen was
<br />234 mm in length and bright red in color ventrally. The second hybrid, a
<br />}'?drmtc
<br />Bluehead sucker 19(.8) 16(*) 16(*) 51(*)
<br />Caio.stomus discobolus)
<br />Colorado squawfish I(•) 7(*) 8(*)
<br />111%, hochellus lucius)
<br />Flannehnouth sucker 302(13.1) 732(7.8) 681(8.5) 1715(8.7)
<br />Catostomus latipinnis)
<br />Roundtail chub 441(19.2) 1087(11.5) 639(8.0) 2167(11.0)
<br />(;tla robusta)
<br />speckled dace 190(21.3) 949(10.1) 226(2.8) 1665(8.4)
<br />R hoo('lttlivs osculus)
<br />i 0I kL ENDEMIC 1252(54.5) 2785(29.6) 1569(19.6) 5606(28.5)
<br />'•rtrndwed
<br />Isla, k bullhead 15(.6) 9(*) 27(*) 51(*)
<br />11 tahtrus melas)
<br />_11 1) 63(2.7) 179(1.9) 278(3.5) 520(2.6)
<br />(:I'prmuscarpio)
<br />(.h.mnel catfish 5(*) 22(*) 960.2) 123(.6)
<br />1,ta4uus punctatus)
<br />Rnhcad minnow 60(2.6) 394(4.2) 632(7.9) 1086(5.5)
<br />l'tmephales promelas)
<br />(.rern sunfish 2(*) I(•) 3(*)
<br />L.rpomis Cvanellus)
<br />Red shiner 885(38.5) 6019(64.1) 5399(67.5) 12303(62.5)
<br />otropis lutrensis)
<br />u1 U. INTRODUCED 1028(44.7) 6625(70-4) 6433(80.4) 14086(71.5)
<br />U, FISH 2280(100) 9410(100) 8002(100) 19692(1011)
<br />I!" 1.Iblr excludes one bn)un it. one Gila elegans hybrid and one humpback ticker X Ilannelnxnuh xlckrr h0o,
<br />ctcorback sucker (Xyrauchen texanus) X flannelmouth sucker, was captured
<br />Ih km above the confluence of the Green River on 12 July 1979. This com-
<br />Ilnation has been well documented by Hubbs and :Miller (1953). Identifica-
<br />'Itm was based on body shape, coloration, number of scales, and number of
<br />lorsal and anal fin rays (Minckley, 1973). This fish was a ripe male, 465 mm
<br />.n length, with tubercles on the anal and caudal fins.
<br />DISCUSSION.-Native fishes made up 54.5% of the fish fauna at stations I to
<br />l in the upper Utah portion of the White River. In the middle and lower
<br />sections of the river (Stations to 5 to 15), introduced species were dominant,
<br />making up 80.4% of the fish fauna (Lanigan and Berry, 1979). During 1974-
<br />Crosby (1975) found endemic fishes more abundant at all but two of the
<br />'-IKht stations in the middle and lower section of the river. During the 5-year
<br />Interval between these two studies, introduced species obviously have been
<br />(''Placing endemic species. This pattern of endemic fish displacement is sim-
<br />lar to that found in several other western rivers and streams (McAda et al.,
<br />19811; Holden and Irvine, 1975; Deacon and Bradley, 1972: Cross, 1976). Hab-
<br />`f:It deterioration and reduced diversity generally have coincided with expan-
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