Scientific Name: Catostomus discobolus yarrowi Common Name: Zuni bluehead sucker BISON No.: 010496

Legal Status: ¾ Arizona, Species of ¾ ESA, Proposed ¾ New Mexico-WCA, Special Concern Threatened Threatened ¾ ESA, Endangered ¾ ESA, Threatened ¾ USFS-Region 3, ¾ ESA, Proposed ¾ New Mexico-WCA, Sensitive Endangered Endangered ¾ None

Distribution: ¾ Endemic to Arizona ¾ Southern Limit of Range ¾ Endemic to Arizona and ¾ Western Limit of Range New Mexico ¾ Eastern Limit of Range ¾ Endemic to New Mexico ¾ Very Local ¾ Not Restricted to Arizona or New Mexico ¾ Northern Limit of Range

Major River Drainages: ¾ Dry Cimmaron River ¾ Rio Yaqui Basin ¾ Canadian River ¾ Wilcox Playa ¾ Southern High Plains ¾ Rio Magdalena Basin ¾ Pecos River ¾ Rio Sonoita Basin ¾ Estancia Basin ¾ Little Colorado River ¾ Tularosa Basin ¾ Mainstream Colorado River ¾ Salt Basin ¾ Virgin River Basin ¾ Rio Grande ¾ Hualapai Lake ¾ Rio Mimbres ¾ Bill Williams Basin ¾ Zuni River ¾ Gila River

Status/Trends/Threats (narrative): Federal: FWS Species of concern, USFS Sensitive: Region 3, State AZ: Species of concern, State NM: Endangered. Status The Zuni bluehead sucker was once common in the Little Colorado River and Zuni River drainages, but its historic range has been reduced by approximately 50% (Propst and Hobbs 1996) and its numbers by about 90% in the last 25 years (NMDGF 2000). The Zuni bluehead sucker currently inhabits less then 10% of its probable historic range, and within its current range, its distribution is fragmented, and its status in Arizona is uncertain (Propst 1999). Merkel (1979) reported that on July 21 1971, a sizable population of Zuni Mountain suckers was discovered deep in the Nutria Box where water was flowing. Biologist had assumed that the suckers had been extirpated as a result of fish eradication efforts in the 1960's. On May 13, 1972, population of Zuni Mountain suckers was located in a small tributary of Tampico Draw that originates on the property of Steve Radosevich. This sucker population originated from an introduction made by Radosevich in the 1930's (Merkel 1979). Fish eradication efforts in the 1960s eliminated the subspecies from portions of the Zuni River drainage in New Mexico. It no longer occurs in Zuni River and only incidentally in Rio Pescado and lower Rio Nutria, a range reduction of about 90% in New Mexico. Reduction of range to ca. 15 km of Rio Nutria headwaters, limited connectivity among remnant populations, and restriction of each to short permanently-watered reaches (< 2 km ) make persistence of Zuni bluehead sucker tenuous (Propst et al 2001). The Rio Pescado, Nutria, and Radosevich populations are relatively secure, although reproductive success is extremely limited in the former stream (Sublette et al 1990). Recent collecting efforts indicate that the sucker has declined dramatically in the Rio Pescado and it is absent in several formerly inhabited reaches of the Rio Nutria (Hobbes and Propst 1995). The Zuni bluehead sucker no longer occurs in Zuni River and only incidentally in Rio Pescado and lower Rio Nutria, a range reduction of about 90% in New Mexico (Propst et al 2001). Trend On July 22, 1975, representatives of USFWS, NMDGF and Zuni Tribe transferred Zuni Mountain suckers from Radosevich Creek to four other streams. The purpose of this transfer was to reintroduce the suckers into waters where they formally occurred or were thought to have occurred (Merkel 1979). Threats Much of the Colorado system today is composed of large reservoirs with cold, clear tail water, and along with water diversions, have had a pronounced negative effect on the native fish fauna (Holden and Stalnaker 1975). The Zuni bluehead sucker has become imperiled in the last 100 years due to adverse affects of poor watershed management activities including: logging, road construction, over-grazing by livestock, reservoir construction, irrigation withdrawals, and stocking of exotic fishes (Propst and Hobbs 1996, NMDGF 2000). Habitat degradation, mainly excessive siltation of streams, is the primary threat to the species (NMDGF 2000). Natural events (e.g., drought or scouring floods), land-use practices causing elevated sediment deposition, or introduction of piscivorous nonnative fish species could eliminate any remnant population (Propst et al 2001). Fine sediments reduce or prevent production of algae, the primary food of the species, and these fine sediments, if mobilized during the spawning season, may smother recently spawned eggs (Propst and Hobbs 1996). Loss of food (diatoms and algae) as a result of sediment deposition poses a threat to extant populations of Zuni bluehead sucker (Propst 1999). It has been suggested that the Zuni bluehead sucker has evolved from introgressive hybridization between bluehead sucker and the Rio Grande sucker with the latter species having gained access to the headwaters of the Zuni River (Colorado River drainage) from Rio San Jose (Rio Grande drainage) by a Pliocene stream capture (Smith 1966, Hobbes and Propst 1995) (Sublette et al 1990).

Distribution (narrative): Cope and Yarrow (1875) reported the first two specimens of this species were obtained by the expedition of 1873 in the Zuni River, a tributary of the Colorado River. The paucity of collections makes accurate characterization of the historical distribution of Zuni bluehead sucker problematic (Propst et al 2001). Zuni bluehead sucker historically (pre-1975) occurred in headwaters of much of the Little Colorado River drainage upstream of Grand Falls, Arizona (Propst et al 2001). The Zuni mountain sucker is endemic to headwater streams of the Zuni River drainage in west-central New Mexico and east-central Arizona, and there, the species occurs mainly in the Rios Pescado and Nutria and Radosevich and Dean creeks in New Mexico and Kin Li Chee Creek in Arizona (Sublette et al. 1990, Propst and Hobbes, 1996, Propst et al 2001). The Zuni bluehead sucker, which is restricted to the upper Zuni drainage is confined to the Little Colorado River basin in Rios Pescado and Nutria along with Radosevich and Dean creeks, all upstream of Zuni, New Mexico and in Kin Li Chee, Arizona (Sublette et al 1990). In New Mexico, its historical distribution was documented in the Zuni River downstream and upstream of the Pueblo of Zuni and moderate numbers were collected in the two principal tributaries, the Rios Pescado (Hobbes and Propst 1995). The Zuni bluehead persists mainly in small, semi-isolated populations in upper Rio Nutria and its headwaters (Propst et al 2001). Fish eradication efforts in the 1960s eliminated the subspecies from portions of the Zuni River drainage in New Mexico (Propst et al 2001).

Key Distribution/Abundance/Management Areas: Panel key distribution/abundance/management areas:

Breeding (narrative):

Habitat (narrative): The distribution of the Zuni bluehead suckers corresponds to the relative rocky substrate in the various areas, and is usually collected over rocky bottom and was common in riffles (Holden and Stalnaker 1975, Hobbes and Propst 1995). Holden and Stalnaker (1975) collected the Zuni bluehead sucker in the sandy bottom reaches in clear water of the study area only over a few rocky areas created by talus slopes extending into the river. While this species occupies a variety of habitats from headwater streams to large rivers, it is almost always moderate to fast flowing water above rubble-rock substrate (Sublette et al 1990). Propst and Hobbes (1996) found the subspecies mainly in pool-runs (0.5 to 1.0 m deep) with water velocity <10.0 cm/sec. These habitats mainly had bedrock, boulder, and large cobble substrates. Propst et al (2001) reported the Zuni bluehead sucker was found most commonly in shaded pools and pool-runs (0.3 to 0.5 m deep) with water velocity < 10 cm/sec where the substrate varied from gravel, cobble, and boulders to bedrock. The Zuni bluehead sucker was rare or absent where the substrate was predominantly sand and silt (Propst 1999, Propst et al 2001).

Breeding Season: ¾ January ¾ June ¾ October ¾ February ¾ July ¾ November ¾ March ¾ August ¾ December ¾ April ¾ September ¾ May

Panel breeding season comments:

Aquatic Habitats: Large Scale: Small Scale: ¾ Rivers ¾ Runs ¾ Streams ¾ Riffles ¾ Springs ¾ Pools ¾ Spring runs ¾ Open Water ¾ Lakes ¾ Shorelines ¾ Ponds ¾ Sinkholes ¾ Cienegas ¾ Unknown ¾ Variable

Panel comments on aquatic habitats:

Important Habitat Features (Water characteristics): Current Gradient Water Depth ¾ Fast (> 75 cm/sec) ¾ High gradient (>1%) ¾ Very Deep (> 1 m) ¾ Intermediate (10-75 ¾ Intermediate Gradient ¾ Deep (0.25-1 m) cm/sec) (0.25-1%) ¾ Intermediate (0.1-0.25 ¾ Slow (< 10 cm/sec) ¾ Low Gradient m) ¾ None (<0.25%) ¾ Shallow (< 0.1 m) ¾ Unknown ¾ None ¾ Unknown ¾ Variable ¾ Unknown ¾ Variable ¾ Variable

Panel comments on water characteristics:

Important Habitat Features (Water Chemistry) Temperature (general) Turbidity Conductivity ¾ Cold Water (4-15°C) ¾ High ¾ Very High (> 2000 ¾ Cool Water (10-21°C) ¾ Intermediate μS/cm) ¾ Warm Water (15- ¾ Low ¾ High (750-2000 27°C) ¾ Unknown μS/cm) ¾ Unknown ¾ Variable ¾ Intermediate (250-750 ¾ Variable μS/cm) ¾ Low (< 250 μS/cm) ¾ Unknown ¾ Variable Panel comments on water chemistry:

Important Habitat Features (Structural elements): Substrate Cover ¾ Bedrock ¾ Rocks, boulders ¾ Silt/Clay ¾ Undercut banks ¾ Detritus ¾ Woody debris ¾ Sand ¾ Aquatic vegetation ¾ Gravel ¾ Rootwads ¾ Cobble ¾ Not important ¾ Boulders ¾ Overhanging ¾ Unknown vegetation ¾ Variable ¾ Unknown ¾ Variable

Panel comments on structural elements:

Diet (narrative): Zuni bluehead suckers feeds by scrapping diatoms and algae from bedrock, boulders, and cobble in its pool and pool-run habitats (Propst 1999, Sublette et al 1990). Periphytic and perilithic algae was generally abundant in reaches where Zuni bluehead sucker was common (Sublette et al 1990). Bluehead suckers feed on aufwachs assemblage of rubble and gravel as do other members of the subgenus. Finer interstitial sediments are sometimes ingested along with the organisms consumed (Sublette et al 1990).

Diet category (list): ¾ Planktivore ¾ Herbivore ¾ Insectivore ¾ Piscivore (Fish) ¾ Omnivore ¾ Detritivore

Grazing Effects (narrative): Timber harvest and livestock overgrazing have been the primary causes of watershed destabilization and resulting alteration of stream habitats mainly through erosion caused by livestock concentrating in flood plains (Propst 1990). Propst (1999) reported the habitat in these areas is relatively unimpacted by current human-associated activities, however, livestock grazing causes local disturbance of habitats such as bank chiseling and increased sediment loading. Livestock overgrazing increases soil erosion in the watershed, thus diminishing fish habitat quality. Livestock grazing is much of the upper Rio Nutria water shed contributes to sedimentation of occupied habitats (Propst 1990, 1999). Livestock grazing in riparian zones has been found to negatively affect water quality and seasonal quantity, stream channel morphology, hydrology, riparian zone soils, instream and streambank vegetation, and aquatic and riparian wildlife (Belsky et al 1999). In June and July, 1978 the Forest Service fenced off a section of Radosevich Creek on the Cibola National Forest to protect the stream from adverse cattle impacts. Cattle had been polluting the water and breaking down the stream banks. A healthy population of Zuni Mountain suckers is found in this portion of the stream (Merkel 1979).

Panel limiting habitat component relative to grazing and comments:

Panel assessment: Is this species a priority for selecting a grazing strategy? Throughout the species’ distribution in New Mexico and Arizona YES NO UNKNOWN In key management area(s) YES NO UNKNOWN

Principle Mechanisms Through Which Grazing Impacts This Species (list): **May be Revised** ¾ Alteration of bank ¾ Altered bank ¾ Increased turbidity structures vegetation structure ¾ Other biotic factors ¾ Alteration of substrate ¾ Change in food ¾ Parasites or pathogens ¾ Alteration of water availability ¾ Population genetic regimes ¾ Change in water structure loss ¾ Altered stream channel temperature ¾ Range improvements characteristics ¾ Change in water ¾ Trampling, scratching ¾ Altered aquatic quality ¾ Unknown vegetation composition ¾ Habitat fragmentation

Panel causal mechanisms comments:

Authors • Draft: Magaña, H.A. • GP 2001: • GP 2002: • Revision:

Bibliography:

Belsky, A.J., Matzke, A., and Uselman, S. 1999. Survey of livestock influences on stream and riparian ecosystems in the western United States. Journal of soil and water conservation 54 (1): 419-431.

Cope, E.D. and Yarrow, H.C. 1875. Report upon the collections of fishes made in portions of Nevada, Utah, California, Colorado, New Mexico, and Arizona during the years 1871- 1974 by Prof. E.D. Cope and H.C. Yarrow. Zoology of the Wheeler Survey west of the 100th meridian, 1875. Washington D.C. 1875.

Hobbes, A.L., Propst, D.L. 1995. Status and Distribution of Zuni bluehead sucker in the Zuni River drainage, New Mexico. Proceedings of the Desert Fishes Council. Death Valley National Park Furnace Creek, California, U.S.A. Nov. 17-20, 1994.

Holden, P.B. and Stalnaker, C.B. 1975. Distribution and abundance of mainstream fishes of the middle and upper Colorado River Basins, 1967-1973. Transactions of the American Fisheries Society 104 (2): 217-231.

Merkel, T.J. 1979. Fishery activities affecting the Zuni Mountain sucker Catostomus dicobolus yarrowi. U.S. Fish and Wildlife Service, Albuquerque, NM.

New Mexico Dept. Game and Fish. 2000. Zuni bluehead sucker, Catostomus discobolus yarrowi In: Threatened and endangered species of New Mexico Biennial review and recommendations. Santa Fe, NM.

Propst, D.L. 1990. Life History and Status of the Zuni Mountain Sucker in the Zuni River Drainage, New Mexico. NMDFG study plan. Albuquerque, NM.

Propst, D.L. 1999. Threatened and endangered fishes of New Mexico. New Mexico Game and Fish Technical Report 1. Santa Fe, New Mexico. 84 pp.

Propst D.L. and Hobbes A.L. 1996. Distribution, status, and notes on the biology of Zuni bluehead sucker, Catostomus discobolus yarrowi, in the Zuni drainage, New Mexico. Project completion report (E-25), New Mexico Dept. of Fish and Game, Santa Fe, New Mexico.

Propst L., D., Hobbes L., A., Stroh L. T. 2001. Distribution and Notes on the Biology of Zuni Bluehead Sucker, Catostomus Discobolus Yarrowl, in New Mexico. The Southwestern Naturalist 46 (2): 158-170.

Smith, G.R. 1966. Distribution and evolution of the North American catastomid fishes of the subgenus Pantosteus, genus Catostomus. Miscellaneous publications of he Museum of Zoology, University of Michigan 129.

Sublette, J. E., M. D. Hatch, and M. Sublette. 1990. The fishes of New Mexico. University of New Mexico Press, Albuquerque, NM.