Creat &Isio N:l.luraUst 50(3), 1900, pp. 243-248 CONSERVATION STATUS OF THREATENED FISHES IN WARNER BASIN, OREGON 1 l 3 Jack E. Williams , MarkA. Stern \ Alan V. Munhall , and Cary A. Anderson"" A8S'TRACT.-Two fedemlJy listed fisbes, the Foskett speckled daceand Warnersucker, are endemic to Warner Basin in south central Oregon. The Foskett speckled dace is native only to a single spring in Coleman Valley. Anearby'spring was stocked with dace in 1979 and 1980, and now provides a second population. The present numbers ofdace probably are at their Wgbest levels since settlement ofthe region. 'The Warner sucker historically occurred throughout much of the Warner Valley, but its distribution and abundance have been reduced by construction ofreservoirs and irrigation dams and the introduction of predatory game fishes. Lentic habitats have become dominated by introduced fishes, particularly white crappie, black crappie, and brown bullhead. The largest remaining IXlPulation ofWarner suckers occurs in Hart Lake, where successful reproduction was documented but there is no evidence of recruitment to the adult population. Two threatened fishes inhabit separate val­ Deep (= Warner) Creek near Adel. The leys in Warner Basin, Oregon. In Coleman Warner sucker was listed as threatened pri­ Valley the only native fish is the Foskett marily because of fragmentation of stream speckled dace, Rhiuichthys osculus ssp., habitats by irrigation diversion dams and the which occurs in Foskett Spring along the west establishment of large populations of intro­ margin oftbe Coleman Lake bed. The lake is duced piscivorous fishes in lentic habitats dryexcept during years ofexceptional rainfall. (U.S. Fish and Wildlife Service 1985b). The dace was listed as threatened because of Long-time residents recalled that during small population size, trampling of its re­ the 1930s large numbers ofspawning Warner stricted habitat by cattle, and subsequent suckers (referred to as "redborse") ascended degradation ofthe springpool area (U.S. Fish Honey Creek far into upstream canyon areas and Wildlife Service 1985a). (Andreasen 1975). By the 1970s the species To provide a refuge population free of range was fragmented by numerous irriga­ tion diversion dams on the lower reaches of the effects of intense livestock grazing, 50 streams tributary to Pelican, Crump, and dace from Foskett Spring were transplanted Hart lakes (Andreasen 1975, Kohetich 1977, on 14 November 1979 into an unnamed spring Swensen 1978, Coombs et a1. 1979, Hayes (now known as "Dace Spring") on Bureau of 1980), which block spawning runs from the Land Management (BLM) land approxi­ lakes into streams. mately 1.5 km south of Foskett Spring. An­ Coombs et al. (1979) found that although other 50 dace were transferred into the spring habitats bad been fragmented resident stream on 26 August 1980. A reprodUcing population populations still persisted. Nearly two-thirds subsequently established in Dace Spring, and ofall adult suckers (198 of300) were captured more than 300 dace ofthree size classes were by Coombs et a1. (1979) in the canal between observed there in 1986 (BLM Lakeview Dis­ Anderson and Hart lakes, immediately north trict, unpublished data). of the Hart Lake spillway. Adult and larval The presumed historical range ofthe War­ suckers also were captured in Snyder Creek, ner sucker, Catostomus warnerensis, con­ in Honey Creek above the dam at Plusb, at sisted of the main Warner lakes (Pelican, the mouth of Honey Creek in Hart Lake, at Crump, and Hart) and other accessible lakes the south end ofWarner Valley in Twentymile and sloughs in Warner Valley, and low- to Creek between the south end of the valley moderate-gradient reaches of tributary floor and the confluence with Twelvemile streams. The species description by Snyder Creek, and in Twelvemile Creek immediately (1908) was based on specimens collected from above and below the O'Keefe Diversion Dam. IDivi$ioll ofWiJdlile and Fisheries. Bureau ofLand r.bn~tne1lt, 18th <\ C Sb'eets, N. W.• \\~biopon, D. C. 20240. :iJhe Nature Conser'vallCy• .L205 Northwest 25th ....vetlue, Portand, ~ mlO. 1Jureau of L.nd M~g(:roent.BoJIISl. Lakeview. Oregoo 97630. ~('goD DepanmentofFlsh and \'t1Idlife. 8oJI12l4, Lakeview, Oregon 97630. 243 244 J. E. WILLIAMS ET AL. [Volume 50 In 1980 Coombs and Bond (1980) sampled lakes by use oftraps, gill nets, and seines, and Z2 sites throughout the basin, capturing 46 from streams with dip nets, trap nets, elec­ Warner suckers at 4 localities: Honey Creek troshocker, kick nets, and seines. Most fishes between Hatt Lake and the datn at Plush, were identified, measured, and returned to canals ofDeep Creek at the eastend ofPelican their habitat. Voucher specimens or those ac­ Lake, the spillway immediately north ofHart cidentally killed during collecting are housed Lake, and Swamp Lake. In 1983 Smith et al. at the Wildlife and Fisheries Museum, Uni­ (1984) captured 1 adolt Warner sucker in versity of California, Davis. Opercles from Crump Lake and 2 juveniles (approximately five suckers were aged according to the meth­ 130 mm total length [TL]) in Deep Creek ods described by Scoppettone (1988). Visual between Adel and the falls. In 1987 an adult observations were made of spawning Warner Warner sucker was caught by an angler along suckers in Honey Creek. the slongh just south of Flagstaff Lake a. E. Williams, personal observation). FOSKETI SPECKLED DACE This paper summarizes the current status ofthese two threatened fishes, as determined In 1987 the BLM acquired Foskett Spring by surveys conducted from 1987 to 1989. and the surrounding 65 ha, ofwhich approxi­ Other native fishes ofWarner Valley include a mately 28 ha were fenced to exclude cattle. local rorm of redband trout (Oncorhynchus The dace population at Foskett Spring has mykiss ssp.), tui chub (Gila birolor), and the since expanded to the spring pool its outflow, common form of speckled dace (R. o.culus). and downstream marsh. Baseline water qual­ The Warner Valley redband trout largely has ity and vegetation monitoring at Foskett and been displaced by introduced trout and is Dace springs were initiated by BLM in 1987. listed as "ofspecial concern" by the American TI,e following data collected on 28 September Fisheries Society (Williams et al. 1989). 1988 from Foskett Spring and Dace Spring, respectively, exemplify the two habitat simi­ HABITAT DESCRIPTION AND SURVEY METHODS larities: air temperature 19 and 17 C, water temperature 17 and 16 C, dissolved oxygen The Warner Basin comprises 6858 sq km in 5.3 and 5.9 mg/I, conductivity 350 and 250 sonth central Oregon and small portions of mohs/cm, pH 8.1 and 8.2, alkalinity 114 and northeastern Californiaand northwestern Ne­ 99 mg/l CaC03, hardness 40.0 and 24.7 mg/l, vada (Fig. 1). Drainage is internal and is di­ and turbidity 1.4 and 1. 8 NTU. vided between Coleman Valley and the much The dace population maintains itself at larger Warner Valley. Coleman Valley is a Dace Spring despite a tendencyfor vegetation separate drainage in the southeastern part of to choke outmost open water. The introduced the basin and receives sparse runoff. Observa­ population has expanded by movementoffish tions oCthe Foskett speckled daceand its habi­ through a connecting pipe into a livestock tatin Coleman Valley were made from 1987 to watering trough just east of the spring. No 1989. Standardized transects were estab­ other fish occur in Coleman Valley. lished along Foskett Spring and its outflow to monitor vegetation recovery following cessa­ WARNER SUCKER tion of grazing, and to qnantify atnonnts of open-water habitat. Surveys on Twentymile Creek above and In Warner Valley all water flows into a se­ below the Dyke Diversion Datn located I ries of north-south oriented shallow Jakes, adult and 2 larval Warner suckers in 1988. sloughs, and potholes. During periods with Additional 1987 and 1988 surveys failed to above-average precipitation, as occurred dur­ locate Warner suckers elsewhere in Twelve­ ing the early 1980s and again in 1989, these mile Creek (including sections in Nevada and lakes fill from the south and eventually over­ Oregon upstream of the Nevada border), the flow into the northern part ofthe valley. Only canal north ofHart Lake, the slough between the three most southerly lakes, Pelican, Flagstaff Lake and Mugwump Lake, the Crump, and Hart, are permanent. Fish col­ slough between Lower Campbell and Catnp­ lections in Warner Valley were made from bell lakes, or Stone Corral Lake. In April 1987 to 1989. Samples were collected from 1989, 28 adult suckers were captured at the 1990] THREAmNED WAIlNEIlBASIN FISHES 245 OREGON Warner Basin Alldt"fJOII I. t N • HurLol!.f oeep Cr. • CnlJu,Ru.. Adell , ~Cok_1I Oregon " FOSkelt· l.llb Twelt'emile Spring -- - ---- - - -- California I Nevada Fig. 1. The Warner Ba.<;in ofsoutb central Oregon. 246 1. E. WILLIAMS ET AL. [Volume 50 T>\IJLE L Frequency offishes collected in Warner Basin during 1987-89. All collection sites are in Lake County, Oregon, unless otherwise noted. Collections made at the same habitat arc combined. -- Large- Warner Tui Speckled White Black mouth Spotted Brown Location sucker elmh dace Troue crappie crappie bass bass bullhead Twelvemile Cl\ 40,j (Washoe Co" NV) 1\velvemile CC 591 51 Dyke Diversion Canal 1 Irrigation canal along 1 I 1 1\ventymilc Cr. • Twentymile Cr. G 25 854 " 2 4 Greaser Heservoir 476 1 2 Deep Creek 400 40 Hart Lake 70 12 1620 14 1 449 lower Honey Creek 69 upper Honey Creek 19 canal north ofHart Lake 7 -" 31 30 1 Anderson Lake ", 10 1 Flagstaff Lake slough 27 107 59 40 sloul{h between Lower 82 39 Campbell and Campbell Campbell Lake :l7I 95 Stone Corral Lake 17 5 Total caught 1'9"" 649 22·69 96 2183 lOG 2 1 607 Relative catch (%) 2.5 10.7 37.4 1.6 26.0 1.7 <0,1 <0,1 IO.O "May indude nalive redband trout Jed/OJ" intmij"cod roinhow trout mouth of Honey Creek in Hart Lake, and 42 Hart Lake, or the canal immediately north of were captured along the east side of Hart the lake.