(DRAFT) - Taxonomy
                                   Species CUI-UI
                                Species Id ESIS251024
                                   Date 14 MAR 96



TAXONOMY

NAME - CUI-UI OTHER COMMON NAMES - CUI-UI; SUCKER, LAKE+, CUI-UI; LAKESUCKER and CUI-UI ELEMENT CODE - CATEGORY - Fish PHYLUM AND SUBPHYLUM - CHORDATA, CLASS AND SUBCLASS - OSTEICHTHYES, ORDER AND SUBORDER - CYPRINIFORMES, FAMILY AND SUBFAMILY - CATOSTOMIDAE, GENUS AND SUBGENUS - CHASMISTES, SPECIES AND SSP - CUJUS, SCIENTIFIC NAME - CHASMISTES CUJUS AUTHORITY - TAXONOMY REFERENCES - COMMENTS ON TAXONOMY - Cui-ui Chasmistes cujus Cope, 1883 KINGDOM: Animal GROUP: Fish PHYLUM: Chordata CLASS: Osteichthyes ORDER: Cypriniformes FAMILY: Catostomidae The cui-ui is a plump, robust sucker (01,06,07,10). The head is very large, wide and somewhat round in cross-section with proportionately small eyes. Its mouth is unsuckerlike being in a ventro-terminal position. Lips are thin and obscurely papillose. The lower lip is somewhat pendant as characterized by the genus and divided by a wide median notch (illustration in Miller and Smith, 1981; 06). Cui-ui are coarsely scaled, with counts of 13-14 above the lateral line, 59-66 along the lateral series and 22-26 around the caudal peduncle. Total body length is 9 times that of the dorsal fin base. Fin ray counts are: dorsal, 10-12; anal, 7; and caudal, 8 or less. The caudal fin is weak to moderately forked and the caudal peduncle is thick, least depth about 12 times body standard length. Pharyngeal teeth are delicate, the last pharyngeal arch bears a row of more than 10 comb-like teeth confined to a single row. Gill rakers are numerous, 44 on first left arch, and branched like broccoli Taxonomy - 1 (DRAFT) - Taxonomy Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 (illustration, 06). The swim bladder is two-celled and the peritoneum nearly black. Both sexes are generally black or brown above, more broken laterally, fading into flat white on the venter. Breeding males develop a reddish to brassy color on the sides as well as nuptial tubercles on their fins. Females have a more bluish cast than males, attain greater length and weight than males, are more stocky in appearance, and have proportionally shorter fins. Also, during the spawning season the vent of females becomes swollen and extended. Diagnostic characters useful in identifying larval and early juvenile cui-ui from other syntopic suckers include differences in pigmentation, size at onset of specific developmental events, and gut and mouth morphologies (02). Taxonomy of the cui-ui is completely stable. With its restricted distribution and distinctive appearance, it is unlikely this species would be confused with any other fish or that individuals would attempt its taxonomic subdivision based on trivial characters (01). Cope 1883: 149 is the taxonomic author for Chasmistes cujus (03). The holotype (ANSP 20523) is a 360 mm standard length specimen in very poor condition (06). The only synonyms proposed for this genus and species are Lipomyzon for C. brevirostris (03) and the subgeneric Pithecomyzon applied by Fowler (04) to Chasmistes cujus. Locations of additional specimens in collections are given in Miller and Smith (06). Other common names used in referring to this fish includes cui-ui lake sucker and cui-ui lakesucker. Photographs of adult cui-ui appear in references 01, 06, 09, and 28 and drawings are in references 01, 07, and 08. Drawings of larval and juvenile cui-ui are included in references 02, 06, 26, and 30. Taxonomy - 2
                                  (DRAFT) - Status
                                   Species CUI-UI
                                Species Id ESIS251024
                                   Date 14 MAR 96



STATUS

Coded Status E: Federal Endangered Commercial/consumption COMMENTS ON STATUS - U.S. STATUSES AND LAWS: The cui-ui (Chasmistes cujus) has been designated as Endangered pursuant to the Endangered Species Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as amended. The species has this status wherever found including the State of Nevada. This species is protected by the Lacey Act (P.L. 97-79, as amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import, export, transport, sell, receive, acquire, or purchase any wild animal (alive or dead including parts, products, eggs, or offspring): (1) in interstate or foreign commerce if taken, possessed, transported or sold in violation of any State law or regulation, or foreign law; or (2) if taken or possessed in violation of any U.S. law, treaty, or regulation or in violation of Indian tribal law. It is also unlawful to possess any wild animal (alive or dead including parts, products, eggs, and offspring) within the U.S. territorial or special maritime jurisdiction (as defined in 18 U.S.C. 7) that is taken, possessed, transported, or sold in violation of any State law or regulation, foreign law, or Indian tribal law. RESPONSIBLE FEDERAL AGENCIES: USFWS -Responsible for the management/recovery, listing, and law enforcement/protection of this species. BIA -Responsible for the law enforcement/protection of this species with applicable State and Federal laws on public lands under their control. Also responsible for management/recovery on Bureau of Indian Affairs lands. All Federal agencies have responsibility to ensure that any action authorized, funded, or carried out by that agency is not likely to jeopardize the continued existence of the species or result in the destruction or adverse modification of Critical Habitat (50 CFR 402), and to utilize their authorities to carry out programs for the conservation of the species. STATE STATUSES AND LAWS: Status - 1 (DRAFT) - Status Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 STATE: Nevada DESIGNATED STATUS: Endangered ADMINISTRATIVE AGENCY: Nevada Dept. of Wildlife STATE STATUTE: Nev. Admin. Code, Sec. 503.015 to 503.080, Dec. 21, 1981. INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS: This species is listed as Endangered by the IUCN Red Data Book (1977) and by the 1986 IUCN Red List of Threatened Animals. This species is also listed in Appendix I of CITES and by the U.S. in the Annex to the Convention on Nature Protection and Wildlife Preservation in the Western Hemisphere (1970). ECONOMIC STATUSES: This fish has some value as food for human consumption. 67/03/11:32 FR 4001 - Final rule, Endangered 79/01/17:44 FR 03636/03654 - Notice of review 79/05/21:44 FR 29566/29577 - Notice of review 85/07/22:50 FR 29901/29909 - Notice of review 87/07/07:52 FR 25522/25525 - Notice of 5-year review Status - 2
     

HABITAT ASSOCIATIONS

HABITAT - AQUATIC INLAND AQUATIC LAND USE - Cropland and Pasture Deciduous Forest Land Streams and Canals Lakes Reservoirs NATIONAL WETLAND INVENTORY CODES NWI NWICLS NWIMOD NWISPEC Riverine, upper perennial UB3 3UB Riverine, upper perennial UB1 Riverine, upper perennial SB3 Riverine, upper perennial SB2 Riverine, upper perennial SB1 Riverine, upper perennial OW0 Riverine, lower perennial UB3 Riverine, lower perennial UB2 Riverine, lower perennial UB1 Riverine, lower perennial SB3 Riverine, lower perennial SB2 2SB Riverine, lower perennial OW0 Lacustrine, littoral UB3 Lacustrine, littoral UB2 Lacustrine, littoral UB1 Lacustrine, littoral RB2 Lacustrine, littoral OW0 Lacustrine, limnetic UB3 Lacustrine, limnetic UB2 Lacustrine, limnetic UB1 Lacustrine, limnetic RB2 Lacustrine, limnetic OW0 COMMENTS ON HABITAT ASSOCIATIONS - Cui-ui are obligate lacustrine suckers with a very restricted distribution, occurring only in Pyramid Lake, Nevada. Adults migrate from Pyramid Lake up the lower Truckee River in spring to reproduce and return to Pyramid Lake immediately following spawning. Larvae emigrate to Pyramid Lake shortly after hatching (01,08,10,14). Habitat of adults in Pyramid Lake is the inshore benthic region. Over 90 percent of gill net catches of adults have been from water 0-15 m depth and none have been captured deeper than 46 m (15). Dominant substrate in this zone of Pyramid Lake are: clay-silt-fine sand, 47 percent; medium sand, 33 percent; tufa boulders and outcrops, 13 percent; and coarse non-tufa material (mostly gravel, rubble and boulders), 6 percent (16). The 0 to 15 m depth approximates the epilimnion in monomictic Pyramid Lake where maximum summer water temperatures in the limnetic zone seldom exceed 23 degrees Celsius (09). Few juveniles cui-ui have been collected from Pyramid Lake and most were collected at depths less than 20 m (17). No published information on larval habitat associations in Pyramid Lake is available. Habitat Associations - 1 Adult cui-ui spawn in Truckee River over predominately gravel substrate at water depths ranging from 21 to 110 cm, with most spawning occurring at depths of 71 to 80 cm (08). Stream velocities range from 27 to 140 cm/s and near bed velocities 21-90 cm/s. Most spawning was reported at stream velocities of 101 to 110 cm/s and near bed velocities of 71 to 80 cm/s (08). Stream velocity preferences of larval cui-ui are not known. Cui-ui spawning has also been reported in Pyramid Lake at the entrance of freshwater streams on fine to coarse gravel (18,27) and in the Marble Bluff fishway where the substrate is predominately compacted soil (08). Upstream migrating prespawning adults require pool environments, typically log jam pools, as refugia during the day (28). Koch (19) recommended a safe maximum temperature for adult cui-ui of 20.0-21.6 degrees Celsius (C); stress was reported at temperatures of 21.7 to 23.9 degrees C and the upper incipient lethal temperature range was 25.0 to 29.9 degrees C. Safe maxima for juvenile cui-ui 5 to 18 months old ranged from 23.9 to 25.6 degrees C, stress level 26.2 to 28.0 degrees C and upper incipient level 29.9 to 32.0 degrees C. Koch (20) found 13.9 degrees C was the optimum incubation temperature for cui-ui eggs; 40 percent mortality occurred at 17.8 degrees C and 70 percent mortality at 21.7 degrees C. Mortality of cui-ui eggs fertilized and water hardened in about 775 ohms/cm fresh water was nearly complete when incubated in Pyramid Lake water at salinities of 5.2 to 5.9 g/L (10,21,22). Decreasing mortality following transfer of developing cui-ui embryos to Pyramid Lake water was observed with progressively longer periods of incubation in fresh water, until 4 days when differences in mortality were not significant. By three days post-hatch cui-ui larvae could tolerate 5.8 g/L Pyramid Lake water with less than 10 percent mortality (10,22). Cui-ui juveniles showed reduced survival over 180-day chronic bioassays at Pyramid Lake salinities ranging from 3.6 to 5.2 g/L (10,22). Adult and juvenile cui-ui appear to tolerate the salinity and chemical composition of Pyramid Lake water (pH = 9.2, total alkalinity = 23 meq/L, sodium = 1.7 and chloride = 2.0 g/L, (09). No information is known about oxygen requirements of egg, larval, juvenile or adult life history stages of cui-ui. Levels of unionized ammonia (NH3-N) 1.35 mg/L and higher were reported lethal to cui-ui egg development and larval development has been retarded at ammonia concentrations of 0.15 mg/L and higher (23). Nitrite concentrations as high as 43.7 mg/L NO2-N had no effect on fertilized egg incubation or hatching, but growth of larval cui-ui was retarded at concentrations 22.0 mg/L NO2-N and greater (23). Nitrate had little noticeable effect on cui-ui embryonic development or hatching success at concentrations less than 56 mg/L NO3-N and no effect on larval growth has been detected at nitrate concentrations up to about 82 mg/L (23). The two previous channelization projects administered by the Corps of Engineers on the lower Truckee River, resulted in widening of the channel and the loss of protective cover, leaving many areas exposed to direct sunlight and solar heating. Gone were the deep pools and the shade that had kept water temperatures cool enough to support the fish (18). Where livestock have unlimited access, all of the readily available forage had been removed, leaving the barren ground subject to unlimited erosion during high runoff. Here again, no undergrowth or protective canopy is developing, only the few old willows and cottonwoods have survived, and these periodically topple over into the river when undercut by high runoff, causing mass erosion. Thousands of cottonwood seedlings covered the ground in early summer, but by fall, very few could be found. It is obvious that livestock grazing is having a very detrimental effect on new growth, and has prevented Habitat Associations - 2 the re-establishment of needed protective bank cover in many areas (18). Habitat Associations - 3
                                (DRAFT) - Food Habits
                                   Species CUI-UI
                                Species Id ESIS251024
                                   Date 14 MAR 96



FOOD HABITS

TROPHIC LEVEL - OMNIVORE LIFESTAGE FOOD FOOD PART General Phytoplankton General Diatoms General Algae General Zooplankton General Arthropods Food Habits - 1
                         (DRAFT) - Environment Associations
                                   Species CUI-UI
                                Species Id ESIS251024
                                   Date 14 MAR 96



ENVIRONMENTAL ASSOCIATIONS

G = General A = Adult LIM = Limiting RA = Resting Adult J = Juvenile FA = Feeding Adult RJ = Resting Juvenile BA = Breeding Adult FJ = Feeding Juvenile P = Pupae L = Larvae E = Egg RL = Resting Larvae FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS G Inland wetlands: swamp G Aquatic Features: Pool areas Environment Associations - 1
                               (DRAFT) - Life History
                                   Species CUI-UI
                                Species Id ESIS251024
                                   Date 14 MAR 96



LIFE HISTORY

FOOD HABITS: Food habits and diet of cui-ui are not well known. Most fish captured from Pyramid Lake have been pre-spawning adults which do not appear to feed (07,18). Adults captured at other seasons feed primarily on zooplankton, filamentous algae and aquatic insects (01, 24). In terms of energy content (carbon) zooplankton, primarily cladocerans and copepods, made-up over 90 percent of gut contents of yearling (104-120 mm long) cui-ui from Mud Lake Slough. Chironomid larvae comprised 7 percent, with diatoms and filamentous green and blue-green algae of negligible importance (08). The few juvenile cui-ui collected from Pyramid Lake in 1986 had eaten ostracods and the copepod Cyclops almost exclusively (25). Juvenile cui-ui reared in hatchery raceways have been observed feeding on periphyton along the sides of tanks (10). Larval cui-ui (12-28 mm long) from a natural side channel alongside the Truckee River consumed primarily chironomid larvae (56 percent stomach carbon), following by copepods, cladocerans and ostracods in order of decreasing importance (08). When placed in aquariums containing Pyramid Lake water, larval cui-ui readily consume zooplankton, and selected cladocerans over copepods (26). The large number and highly dissected structure of cui-ui gill rakers (06) and subterminal rather than inferior mouth position (01) indicates this fish is efficient at straining plankton from the water column. This feeding morphology, plus its inshore benthic rather than limnetic distribution (15), suggests juvenile and adult cui-ui in Pyramid Lake feed primarily on benthic zooplankton, although it is likely they feed further off the bottom than species of suckers with ventral mouths (10). HOME RANGE/TERRITORY: There is no evidence that cui-ui are territorial during any life-stage (01,08,10). PERIODICITY: No information is available on diel periodicity of cui-ui in Pyramid Lake. Spawning runs of cui-ui up the Truckee River or Marble Bluff fishway are heaviest in late afternoon and evening, when daily water temperatures are highest (08). Adult spawning in Truckee River occurs primarily at night (2000-0600 hours) followed by nocturnal downstream movement of adults (14). Downstream movement of hatched larval cui-ui is almost exclusively at night primarily between 2200 and 0600 hours (08). Seasonal activity of cui-ui in Pyramid Lake, as evidenced from gill net catches, peaks during late winter and spring (Feb. - May) when fish congregate at the south end of Pyramid Lake to ascend the Truckee River to spawn (10). MIGRATION PATTERNS: The only migratory behavior reported for cui-ui involves adults ascending the Truckee River from Pyramid Lake to spawn, their return to the Lake and downstream migration of hatched larvae (01,08,10,14). Adult cui-ui migrate to the south end of Pyramid Lake from late winter to early spring (Feb. - May) where pre-spawning adults congregate off Life History - 1 (DRAFT) - Life History Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 the mouth of the river (10,15,29). Fish ascend the river or fishway primarily between April through June (01,07,08,14,28) with peak upstream movement usually occurring in May and cued by water temperature and photoperiod (08,11). Diel upstream movements of pre-spawning cui-ui also appear to be temperture related, peaking in late afternoon and early evening and tapering off at night (11). Radio tagged males remained in the Truckee River between 6.5 to 16.5 days and females for 4.0 to 10.5 days before returning to Pyramid Lake (08). Young cui-ui migrate downstream shortly after hatching, primarily from mid-May through mid-July, usually within about one month of peak adult migration (08). Historically cui-ui migrated up the Truckee River as far as Reno, Nevada (about 100 km upstream of Pyramid Lake, (01)), until construction of Derby Dam in 1905 limited their upstream movements to 62 km (01,10,14). Most cui-ui presently migrate only as far upstream as 15-20 km (08,10,14). COVER/SHELTER REQUIREMENTS: It is not known if larval, juvenile, or adult cui-ui require cover or shelter in Pyramid Lake. Upstream migrating pre-spawning adults require pool environments, typically log jam pools, as refugia during the day (28). Migration of larval cui-ui from Truckee River to Pyramid Lake occurs immediately following hatching (08,11) and it is not known what, if any, cover is utilized. Channelization of the lower river by Corps of Engineers resulted in widening the channel and the loss of protective cover, leaving many areas exposed to direct sunlight and solar heating (18). REPRODUCTIVE SITE REQUIREMENTS: Reproductive site requirements are described in detail by Scoppettone et al. (08,14,28). Cui-ui spawn primarily over gravel substrate in water 20 to 110 cm deep often at the head of gravel bars where flow is rapid and relatively free of silt (10). Stream velocities where cui-ui spawning has been observed ranged from 27 to 140 cm/s, with most spawning occurring at velocities of 101 to 110 cm/s. Near-bed velocities ranged from 21 to 90 cm/s, with most spawning occurring at near-bed velocities between 71 and 80 cm/s. Truckee River water temperatures during which peak spawning migrations have occurred range from 9 to 17 degrees Celsius (C), with daily means of 12 to 15 degrees C. Peak migration occurred when minimum mean daily water temperatures reached 12 to 13 degrees C (11). Temperature requirements for incubating cui-ui eggs are described under heading HABITAT ASSOCIATIONS. Koch (19) recommended a safe maximum temperature for adult cui-ui of 20.0-21.6 degrees C, stress was reported at temperatures of 21.7 to 23.9 degrees C and the upper incipient lethal temperature range was 25.0 to 29.9 degrees C. Safe maxima for juvenile cui-ui 5 to 18 months old ranged from 23.9 to 25.6 degrees C, stress level 26.2 to 28.0 degrees C and upper incipient level 29.9 to 32.0 degrees C. Koch (20) found 13.9 degrees C was the optimum incubation temperature for cui-ui eggs; 40 percent mortality occurred at 17.8 degrees C and 70 percent mortality at 21.7 degrees C. REPRODUCTIVE CHARACTERISTICS: Life History - 2 (DRAFT) - Life History Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 Cui-ui first enter the spawning run at 5 to 6 years of age and lengths of 380-420 mm and fish as old as 41 years have been collected from spawning runs (08). Fecundity ranges from 24,000 eggs (432 mm female) to 196,000 eggs (657 mm female) (08). There is one reproductive period per year primarily between April and late June, spawning migrations peaking in May (01,07,08,10). Timing of spawning migration is dependent on temperature and flow characteristics of Truckee River (08,10,11,14). Scoppettone (14) described in detail spawning behavior of cui-ui in Truckee River. Spawning occurs primarily at night (2000-0600 hours) in clusters of 2 to 7 fish, most frequently with a female flanked on either side by a male. No nest is constructed and the demersal, adhesive eggs and sperm are broadcast over a large area (14,27). Males and females spawn repeatedly, often over 100 times, each spawning act lasting 3-6 seconds. Males spawn actively over 4-5 days and females 2.5 to 4 days. There is no aggression among spawners and females spawn with different combinations of males (promiscuity) (14). Length of incubation is temperature dependent. At 13 degrees C in the laboratory incubation to hatching occurred at 9 days (10). Incubation time for hatchery incubated eggs was 13 days at 10 degrees Celsius, 11 days at 13 degrees C, and 6 days at 15.5 degrees C (26). Hatching was first observed in Truckee River channels 7 days after spawning had begun (14). PARENTAL CARE: No parental care occurs for cui-ui. Embryological development has been described by Koch (26), and Bres (30). POPULATION BIOLOGY: Information on the population biology of cui-ui has been developed largely from analysis of spawning adults. Estimated numbers of cui-ui in the pre-spawning aggregation in Pyramid Lake were 187,065 (151,270 to 236,451, 95 percent CI) for 1982 and 103,407 (82,270 to 134,161 95 percent CI) for 1983 (08). Male to female sex ratios in the spawning run from Marble Bluff Fish Facility have been highly variable from 1978 through 1985, ranging between 1.0:0.2 to 1.0:2.5 (11). Variable access to the fishway due to design constraints and flow characteristics are considered the primary cause for these year-to-year differences. Sampling the offshore spawning population in 1985 yielded a sex ratio of 1.0:1.8 males to females (11). Age of cui-ui determined from opercules indicates they are an extremely long-lived fish, 28-41 years, and 97 percent of the 1983 spawning population was from the 1969 year class (08). The major factor limiting cui-ui populations is reproductive success due to restricted access to the lower Truckee River (01,08,10,14). Several years of high Truckee River discharge to Pyramid Lake in the early 1980's resulted in production of sizeable new year classes as evidenced by capture of juvenile cui-ui in Pyramid Lake (08,25,31). No population density objective for recovery of cui-ui has been established (32). However, recovery potential of a stable naturally reproducing cui-ui population appears good if adequate Truckee River flows of (14 degrees Celsius water are provided for spawning from early April through June (10), access of spawning adults to the lower Truckee River at the Life History - 3 (DRAFT) - Life History Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 Marble Bluff Fish Facility is improved (08,11), river water quality is enhanced (10,13,28), water level of Pyramid Lake is stabilized (10), and nutrient loading to Pyramid Lake is not increased (10,13). SPECIES INTERRELATIONSHIPS: Little information on interactions between cui-ui and other species is available. Cui-ui have not been recorded in the diet of Lahontan cutthroat trout (Salmo clarki henshawni). White pelicans Pelecanus erythrorhynchos) has been reported taking cui-ui (08), but this is probably insignificant (34,35). Extensive predation by Lahontan redsides (Richardsonius egregius) on cui-ui eggs in Truckee River occurs during diurnal spawning. Diet and habitat use by cui-ui in Pyramid Lake suggest they may interact with Tahoe suckers (Catostomus tahoensis) and tui chubs (Gila bicolor) although competition has not been demonstrated. Effects of parasites on cui-ui are unknown (10). OTHER LIFE HISTORY DESCRIPTORS: None. Life History - 4
                           (DRAFT) - Management Practices
                                   Species CUI-UI
                                Species Id ESIS251024
                                   Date 14 MAR 96



MANAGEMENT PRACTICES

RESULT MANAGEMENT PRACTICE Beneficial Restricting/regulating human disturbance of populations Beneficial Developing fishways Beneficial Regulating Water Temperature Beneficial Maintaining/Controlling Water Flow Beneficial Beneficial Controlling pollution [thermal, chemical, physical] Beneficial Reforestation Beneficial Stocking captive-reared wild-strain animals Beneficial Restricting Poaching Beneficial Controlling/Restricting Noncommercial Harvest Adverse Predation Existing Predation Adverse Water Temperature Alteration Existing Water Temperature Alteration Adverse Salinity alteration Existing Salinity alteration Adverse Water Level Fluctuation Existing Water Level Fluctuation Adverse Irrigating Existing Irrigating Adverse Reservoirs Existing Reservoirs Adverse Migration barriers Existing Migration barriers Adverse Erosion Existing Erosion Adverse Grazing Existing Grazing COMMENTS ON MANAGEMENT PRACTICES - The primary cause for decline of the Pyramid Lake cui-ui population was disruption of its reproductive cycle (08). Spawning adults have had only restricted access to Truckee River, the only permanent tributary to Pyramid Lake, during the past 50 years (08). Construction of Derby Dam on the Truckee River in 1905 began the transbasin diversion of Truckee River to the Carson River system. In 1915 Lahontan Reservoir was constructed to receive diverted Truckee River water. Except during high water years, nearly half the total annual flow of Truckee River has been diverted from Pyramid Lake (08, 10). Because of droughts and diversion the water level of Pyramid Lake declined over 24 m between 1905 and 1968. As a result an extensive and shallow delta formed at the mouth of the Truckee River in the 1930's and has been a barrier to migrating adults in most years since then (08). A secondary impediment to cui-ui spawning migrations in the past was the physical barrier of dams to passage by migrating cui-ui. Numana Dam (19 km upstream from Pyramid Lake) was reconstructed and a fish ladder installed in the late 1970's; it is no longer a barrier to upstream cui-ui migration. Derby Dam remains the Management Practices - 1 (DRAFT) - Management Practices Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 only barrier to passage by cui-ui to their historical spawning range. Marble Bluff Dam and Pyramid Lake Fishway were constructed in 1976 to enable migrating fish to bypass the delta (08) and they become funtional for cui-ui passage in 1978 (11). Additionally, portions of water stored in an upstream reservoir are reserved to augment water flows required for cui-ui spawning. Recent high river discharge years (1982-1986) have increased the water level of Pyramid Lake nearly 10 m (12) and migrating cui-ui now can ascend the Truckee River directly to Marble Bluff Dam rather than use the Pyramid Lake Fishway. Nevertheless, only a small percentage of adults from the pre-spawning aggregate in Pyramid Lake ascend Truckee River and the number of cui-ui presently passed at Marble Bluff Dam do not appear adequate to recover the species (11). Major attention to facility improvements or construction of a new facility have been recommended (11). Salinity increase of Pyramid Lake as a result of declining lake level has resulted in early 1980's salinity levels (5.0-5.5 g/L) being at or above the optimum for cui-ui (10). High water temperatures have also been suggested as a factor contributing to observed low survival of cui-ui eggs in the lower Truckee River (28). Extensive predation by Lahontan redsides (Richardonius egregius) on cui-ui eggs in Truckee River occurs during diurnal spawning. Diet and habitat use by cui-ui in Pyramid Lake suggest they may interact with Tahoe suckers (Catostomus tahoensis) and tui chubs (Gila bicolor) although competition has not been demonstrated. Factors perceived as future threats to this species include upstream passage of migrating adults over Marble Bluff Dam, adequate Truckee River flows for migrating adults and larvae, proper river water temperatures for incubating embryos and out-migrating larvae, stream bank and channel erosion, increases in Pyramid Lake salinity and Truckee River water quality and nutrient loading to Pyramid Lake (10,11,13). The two previous channelization projects administered by the Corps of Engineers on the lower Truckee River, resulted in widening of the channel and the loss of protective cover, leaving many areas exposed to direct sunlight and solar heating (18). Where livestock have unlimited access, all of the readily available forage has been removed, leaving the barren ground subject to unlimited erosion during high runoff. Here again, no undergrowth or protective canopy is developing, only the few old willows and cottonwoods have survived, and these periodically topple over into the river when undercut by high runoff, causing mass erosion. Thousands of cottonwood seedlings covered the ground in early summer, but by fall, very few could be found. It is obvious that livestock grazing is having a very detrimental effect on new growth, and has prevented the re-establishment of needed protective bank cover in many areas (18). APPROVED PLAN: U.S. Fish and Wildlife Service. 1983. Cui-ui Recovery Plan. First Revision. U.S. Fish and Wildl. Serv., Portland, OR. 25 pp. The primary objective in the cui-ui recovery plan is to restore Management Practices - 2 (DRAFT) - Management Practices Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 and maintain an optimal, self-sustaining population in the Truckee River-Pyramid Lake system. Attainment of an optimal, self-sustaining population in sufficient, secure habitat may allow declassifying to threatened status and perhaps delisting the species. The recovery activities necessary to achieve the primary objective are: 1) Determine biology of the cui-ui (life history and population dynamics); 2) Determine habitat requirements, i.e., migration stimuli, spawning habitat, water quality, water chemistry, and lake habitat; 3) Rehabilitate the Truckee River and Pyramid Lake habitat by determining limiting factors, determining how to accomplish tasks, and mitigating detrimental water management actions; 4) Stabilize the lower Truckee River in a natural course to reduce bank erosion and river's velocity by eliminating shoreline and bank vegetation removal; 5) Restore river canopy by maintaining the shoreline and bank naturally without using channelization which leads to erosion; 6) Identify and manage self-sustaining populations (develop and implement management plans which include determining river flow regimes, monitoring species composition, censusing, and augmenting through hatchery production); 7) Operate hatchery for fish release at preselected sites; 8) Install fish screens and ladders to aid in fish movement; 9) Control illegal dredge and fill in the lower Truckee River under Sec. 404 of the Clean Water Act; 10) Enforce water quality standards to protect cui-ui habitat; 11) Secure and maintain the flow regime required to maintain cui-ui habitat; 12) Improve and maintain fishery facilities to help in fish movement to spawning sites; 13) Protect cui-ui populations by providing interagency cooperation and enforcing laws and regulations against recreational consumption and take; 14) Regulate water temperature through habitat revegetation which will ensure proper shading from solar heating; 15) maintaining and controlling water salinity; and 16) Implement public information and education program. Management Practices - 3
                                   (DRAFT) - References
                                      Species CUI-UI
                                  Species Id ESIS251024
                                      Date 14 MAR 96



     

References

***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE ***** 01 LaRivers, I. 1962. Fishes and fisheries of Nevada. State Fish and Game Comm., Carson City, NV. 02 Snyder, D.E. 1983. Identification of catastomid larvae in Pyramid Lake and the Truckee River, Nevada. Transactions of the Amer. Fish. Soc. 112:33-348. 03 Cope, E.D. 1883. On the fishes of the recent and Pliocene lakes of the western part of the Great Basin and of the Idaho Pliocene lake. Proceedings Philadelphia Acad. Nat. Sci. 1883:134-166. 04 Fowler, H.W. 1913. Notes on catostomid fishes. Proceedings Philadelphia Acad. Nat. Sci. 65:45-60. 05 Cope, E.D. 1879. The fishes of Klamath Lake, Oregon. Amer. Nat. 13:784-785. 06 Miller, R.R., and G.R. Smith. 1981. Distribution and evolution of Chasmistes (Pisces: Catostomidae) in western North America. Occasional Papers of the Mus. of Zool., Univ. of Mich. 696:1-46. 07 Snyder, J.O. 1917. The fishes of the Lahontan system of Nevada and northeastern California. U.S. Bur. of Fish. Bull. 35(1915-1916):31-86. 08 Scoppettone, G.G., M. Coleman, G.A. Wedemeyer. 1986. Life history and status of the endangered cui-ui of Pyramid Lake, Nevada. Fish and Wildl. Res. 1. U.S. Fish and Wildl.Serv., Wash., D.C. 09 Galat, D.L., E.L. Lider, S. Vigg, S.R. Robertso. 1981. Limnology of a large, deep, North American terminal lake, Pyramid Lake, Nevada, USA. Hydrobiologia 82:281-317. 10 Sigler, W.F., S. Vigg, M. Bres. 1985. Life history of the cui-ui, Chasmistes cujus Cope, in Pyramid Lake,Nevada: A review. The Great Basin Nat. 45:571-603. 11 Coleman, M.E. 1986. Evaluation of spawning runs at the Marble Bluff Fish Facility Nixon, Nevada 1978 to 1985. U.S. Fish and Wildl. Serv., Rept. FR1/FAO-86-11. U.S. Fish and Wildl. Serv., Reno, NV. 12 U.S. Geological Survey. 1980-1986. Water resources data, Nevada. Water data rept. NM-80-1 through NV-86-1. Water Resour. Div., U.S. Geological Survey, Carson City, NV. 13 Galat, D.L. 1983. Study concepts paper. Sewage effluent in the lower Truckee River Pyramid Lake: toxicity to fish and biostimulation to aquatic plants. Colo. Coop. Fishery Unit. Colo. State Univ., Ft. Collins. 14 Scoppettone, G.G., G.A. Wedemeyer, M. Coleman, H. Burge. 1983. Reproduction by the endangered cui-ui in the lower Truckee River. Transactions of the Amer. Fisheries Soc. 112:788-793. 15 Vigg, S. 1980. Seasonal benthic distribution of adult fish in Pyramid Lake, Nevada. Calif. Fish and Game 66:49-58. 16 Galat, D.L. 1986. Organic carbon flux to a large salt lake: Pyramid Lake, Nevada, USA. Internationale Revue der Gesamten Hydrobiologie 71:621-654. 17 Carlson, L. Pers. comm. Resour. Dept., Pyramid Lake Fisheries. 18 Koch, D.L. 1972. Life history information on the cui-ui lakesucker (Chasmistes cujus, Cope 1883) endemic to Pyramid Lake, References - 1 (DRAFT) - References Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 Washoe County, Nevada. Ph.D. diss. Univ. of NV, Reno. 343 pp. 19 Koch, D.L. 1982. Temperature tolerance evaluation of various life phases of the cui-ui. Rept. to Pyramid Lake Indian Tribal Enter. Koch and Assoc. Reno, NV. 20 Koch, D.L. 1981. Temperature tolerance evaluations of cui-ui (Chasmistes cujus) fertilized eggs and larvae to swim-up stage. Rept. to Pyramid Lake Indian Tribal Enterprises. Koch and Assoc. Reno, NV. 21 Chatto, D.A. 1979. Effects of salinity on hatching success of the cui-ui. The Progressive Fish-Culturist 41:81-85. 22 Lockheed Ocean Science Labs. 1982. Investigation on the effect of total dissolved solids on the principal components of the Pyramid Lake food chain. Lockheed Ocean Sci. Labs., San Diego, CA. 23 Koch, D.L., E.L. Lider, S.R. Robertson. 1979. Toxic effect evaluation of ammonia, nitrite, and nitrate on cui-ui (Chasmistes cujus). Bioresour. Center, Publ. No. 50011, Desert Res. Instit. Univ. of Nev. System, Reno, NV. 24 Nevada Fish and Game Commission. 1958. Fisheries management report: Pyramid Lake. Lakes Walker, Pyramid and Tahoe investigations, Dingell-Johnson project FAF-4-R. Nev. Fish and Game Comm., Carson City, NV. 25 Pyramid Lake Fisheries. 1986. Pyramid Lake fisheries fishery restoration program. Annual Rept. for FY-86. Pyramid Lake Fish., Sutcliffe, NV. 26 Koch, D.L. 1986. Life history information on the cui-ui lakesucker (Chasmistes cujus, Cope 1883) in Pyramid Lake, Nevada. Biol. Soc. of Nev. Occasional Papers 40:1-12. 27 Koch, D.L. 1973. Reproductive characteristics of the cui-ui lakesuker (Chasmistes cujus Cope) and its spawning behavior in Pyramid Lake, Nevada. Transactions of the Amer. Fish. Soc. 102:145-149. 28 Scoppettone, G.G., M. Coleman, H. Burge, G. Wedemeyer. 1981. Cui-ui life history: river phase. U.S. Fish and Wildl. Serv., an annual rept. Natl. Fish. Res. Cntr., Seattle, Wash., and Fish. Assist. Office, Reno, NV. 29 Sonnevil, G.M. 1981. Evaluation of the cui-ui restoration program: 1977-1980. U.S. Fish and Wildl. Serv., Fish. Assist. Office, special rept., Endangered Species Program. U.S. Fish and Wildl. Serv., Reno, NV. 30 Bres, M. 1978. The embryonic development of the cui-ui Chasmistes cujus (Teleostei, Catostomidae). Master's thesis. Univ. of Nev., Reno. 31 U.S. Fish and Wildlife Service. 1978. Cui-ui Recovery Plan. Cui-ui Recovery Team, Endangered Species Program, Region 1. U.S. Fish and Wildl. Serv., Portland, OR. 32 Pyramid Lake Fisheries. 1985. Pyramid Lake fisheries fishery restoration program. Annual rept. for FY-85. Pyramid Lake Fish., Sutcliffe, NV. 33 Sigler, W.F., W.T. Helm, P.A. Kucera, S. Vigg, G.W. Workman. 1983. Life history of the Lahontan cutthroat, Salmo clarki henshawi, in Pyramid Lake, Nevada. Great Basin Nat. 43:1-29. 34 Knopf, F.L., and J.L. Kennedy. 1980. Foraging sites of white pelicans nesting at Pyramid Lake, Nevada. Western Birds References - 2 (DRAFT) - References Species CUI-UI Species Id ESIS251024 Date 14 MAR 96 11:175-180. 35 Knopf, F.L., and J.L. Kennedy. 1981. Differential predation by two species of piscivorous birds. Wilson Bull. 93:554-556. ***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY ***** 01 Sigler, W.F., S. Vigg, M. Bres. 1985. Life history of the Chamistes cujus Cope, in Pyramid Lake, Nevada: a review. The Great Basin Naturalist 45:571-603. 02 Scoppettone, G.G., M. Coleman, G.A. Wedemeyer. 1986. Life history and status of the endangered cui-ui of Pyramid Lake, Nevada. Fish and Wildl. Res. 1. U.S. Fish and Wildl. Serv., Wash., D.C. 03 Scoppettone, G.G., G.A. Wedemeyer, M. Coleman, H. Burge. 1983. Reproduction by the endangered cui-ui in the lower Truckee River. Transactions of the American Fisheries Society 112:788-793. 04 LaRivers, I. 1962. Fishes and fisheries of Nevada. State Fish and Game Commission, Carson City, NV. 05 Kock, D.L. 1972. Life history information on the cui-ui lakesucker (Chasmistes cujus, Cope 1883) endemic to Pyramid Lake, Washoe County, Nevada. Ph.D. diss. Univ. of NV, Reno. 343 pp. 06 Snyder, J.O. 1917. The fishes of the Lahontan system of Nevada and northeastern California. Bull. U.S. Bur. of Fisheries 35(1915-1916):31-86. References - 3