Desert Fishes Council

34th Annual Meeting

San Luis Potosí, SLP, México

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During April and May of 2002, approximately ¾ mile of tamarisk was removed from the stretch of salt creek south of the trestle to the power line crossing on section 23 T8S, R11E. CDF fire crews were used on 14 crew days to cut tamarisk and place it on the bank away from the stream channel. Thirty gallons of Rodeo were applied in a cut stump method as the tamarisk was being cut. In June 2002 approximately 80% of the tamarisk had re-sprouted. The re-sprouts were treated with an additional 7.5 gallons of Rodeo as a foliar spray with an approximate 40% success rate. No pupfish were found on a subsequent sampling. On lower salt creek one pupfish was found in the fall of 2001 by USGS sampling efforts.

At Dos Palmas Refuge ponds an experiment is underway to test whether grass carp are an effective means of controlling cattail encroachment on desert ponds. In the first phase of the experiment, nine grass carp were introduced to two ponds (3 and 6 fish) at Dos Palmas in May 2002. Subsequent re-sampling of the vegetation is scheduled for October 2002. The two experimental ponds in the first phase of the experiment do not contain pupfish.

The USGS and the USFWS collected pupfish from the experimental population at Dos Palmas for use in a selenium tolerance study. Approximately 100 fish were removed to breed in laboratory tanks.

Salton Sea trapping found pupfish in a majority of marinas as well as in the main body of the Sea. Pupfish were found in Desert Shores Marina, North Shore Marina, Varner Harbor at Salton Sea State Rec Area, Corvina Estates, and an area just south of Salton City Marina. Pupfish were found at depths ranging from 1 to 3 feet and were captured near shore (5-20 feet from shore). Pupfish were also found in the main body of the Sea near the mouth of Varner Harbor. Pupfish were captured approximately 20 feet from shore; water depth was 2 feet. Pupfish were also found in a few drains at the north end of the Sea. Surveys conducted in two drains found pupfish in both; 1000+ breeding fish were observed in one of the drains.

Owens pupfish (Cyprinodon radiosus)

All 5 populations of pupfish (Marvin’s Marsh, off channel ponds at BLM Spring, Warm Spring, Mule Spring, and Well 368) are thriving.

BLM Spring channel continues to be infested with largemouth bass, but has been the focus of a joint CDFG-BLM restoration project. Much of this work was conducted by engineering intern Genevieve Park of MIT. The lower of two dams was breached and emergent vegetation was greatly reduced by mowing. Mechanical removal of bass by electrofishing and spearing was briefly successful at removing bass, which then recolonized through the failing gravel percolation barriers. A low head (~8”) fish barrier has been installed and appears to be working.

Calcareous deposits in the Mule Spring water supply pipe required clearing with a power snake.

130 small Tamarisk trees and two Russian Olive trees were removed by weed wrench from Well 368 with little regrowth.

Mohave chub (Gila mohavensis)

Mohave chub continue to inhabit Lake Tuendae and “M-C Spring” at Fort Soda in Mojave [sic] National Preserve, The Lark Seep system on China Lake Naval Air Weapons Station, and two artificial ponds at Camp Cady State Wildlife area.

The National Park Service deepened the west half of Lake Tuendae by dredging to counteract encroachment by emergent vegetation, and improve habitat for chubs and Saratoga Springs pupfish. The East half of the “lake” has previously been dredged with very desirable results. Gambusia inexplicably appeared in Lake Tuendae, coincident with an apparent major decline in abundance of Saratoga Springs pupfish at the same site. A 100% infection rate of Asian tapeworm (Bothriocephalus achelognathii) was identified in samples of Lake Tuendae tui chub by the late Dr. Boris Kuperman and Dr. Victoria Matey of San Diego State University.

An unidentified poeciliid, possible an all female clone of Gambusia affinis X holbrooki, was tentatively identified by Dr. Jeff Seigel (Los Angeles County Museum of Natural History) in samples from a fire protection reservoir adjacent to the chub ponds at Camp Cady.

Owens tui chub (Gila bicolor snyderi)

Putative pure Owens chubs exist in 6 locations: AB Spring and CD Spring at Hot Creek State Fish Hatchery, the Owens River Gorge, White Mountain Research Station, Mule Spring, and Cabin Bar Ranch.

A joint study by CDFG and UC Davis to assess taxonomic status using meristics, morphometry, and DNA approaches is in the final year. Specimens sacrificed for this study are being evaluated for fish parasites by Dr. Victoria Matey, San Diego State University, CA.

Chubs in AB Spring exhibit poor health variously exhibiting excessive intraperitoneal fluid, hypertrophied liver, lesions around anal opening, exopthalmia, red eyes, and curved spinal cord.

Many chubs at Mule Spring exhibit frayed caudal fins, attributed to fin nipping by abundant Owens pupfish.

Owens speckled dace (Rhinichthys osculus ssp)

The population known as “Long Valley dace” known only from Whitmore Pond remains abundant but has a high infection rate of both the monogenean Gyrodactylus sp and trematode Clinostomum sp.

Recovery goals for the large river endangered fishes of the Colorado River Basin were finalized this summer and the notice of their availability will be posted shortly in the Federal Register. Flow recommendations are being developed for the two tributaries to the Green River, the White and Duchesne Rivers. Negotiations between the Fish and Wildlife Service and the Upper Basin Recovery Program continue on the Gunnison River flow recommendations. The Bureau of Reclamation will have a draft Environmental Impact Statement regarding the reoperation of Flaming Gorge Dam in September. The reoperation is based on Green River flow recommendations provided by the Upper Basin Recovery Implementation Program. Population estimates of Colorado Pikeminnow in the Green River have been obtained for the entire Green River system for two complete years. The initial estimate was encouraging, estimates for the second year have not been calculated at this time. In addition, population estimates for three consecutive years were also completed for humpback chub Gila cypha in Black Rocks, Westwater and Yampa canyons. The Upper Basin experienced a severe drought in 2002, and nonnatives, particularly smallmouth bass Micropterus dolomieu numbers seem to be increasing in the Yampa River. Northern pike Esox lucius removal efforts are continuing in the Green and Yampa Rivers. Fewer numbers of northern pike were observed in the Green River, while no difference was observed in the Yampa River. Some encouraging experimental results were observed in applying the ‘reset’ approach to management of off-channel wetlands to enhance survival of larval and juvenile razorback sucker and bonytail G. elegans. Experimental pens were stocked with nonnative densities consistent with expected numbers following initial connection of the river. Larval razorback sucker and bonytail were stocked with nonnatives and survival was encouraging.

Harvest of hatchery-produced razorback sucker from grow-out ponds in Grand Junction has begun. About 3,000 fish (300 + mm TL) have been stocked to date in the Upper Colorado River. An additional 7,000 fish will be harvested and stocked this fall. Stocking plans call for three stocking sites — Colorado River near Rulison, Gunnison River near Delta, and Colorado River near Grand Junction. Because the first two sites are upstream from large diversion canals taking most of the river flow, all fish have been stocked near Grand Junction to prevent their entrainment in the canals. Larval razorback sucker were collected this spring and are believed to be offspring of stocked fish.

In the San Juan River, augmentation of Colorado pikeminnow and razorback sucker is continuing and results to date are very encouraging. The San Juan River Recovery Implementation Program continues to make significant progress towards recovery.known only from Whitmore Pond remains abundant but has a high infection rate of both the monogenean Gyrodactylus sp and trematode Clinostomum sp.

In the Virgin River basin, a five-year effort to repatriate Virgin spinedace Lepidomeda mollispinis mollispinis in upper Beaver Dam Wash in Nevada does not appear to have been successful and additional repatriation alternatives are being considered.

In the Virgin River, spring and fall sampling by the Virgin River Recovery Team at three sites in Nevada produced no woundfin Plagopterus argentissimus and only a single Virgin River chub Gila seminuda, at the Bunkerville Diversion in fall. Mask and snorkel surveys were completed along several mainstem Virgin River segments in Arizona and Nevada to provide baseline inventories for chub. In Arizona, the July survey counted 33 adults and 147 juvenile chub. In Nevada no chub were recorded during the August survey. Most striking was the high number of large channel catfish Ictalurus punctatus found throughout the mainstem river. In all 2002 surveys, Tilapia Tilapia sp.. the most recent nonnative to invade, was not found along any of the reaches until September 25 when small numbers were found at Halfway Wash. Upstream, red shiner Cyprinella lutrensis was found above Washington Fields Diversion in the only area of the river previously free of this species. They are thought to have come from a bait pond. Efforts to propagate woundfin at Utah’s Wahweap Hatchery have met with setbacks, but stocks still are held at Dexter National Fish Hatchery.

In the Little Colorado River basin, drought conditions forced salvage operations for Little Colorado spinedace Lepidomeda vittata in Yeager, Leonard, and West Leonard Canyons in the East Clear Creek drainage. Less than 46 spinedace (8 from Yeager, 38 from Dines Tank in Leonard Canyon) were placed into the refugia pond at the Flagstaff Arboretum. From West Leonard Canyon, 363 spinedace were captured, of which 200 were placed at the Arboretum and 57 were stocked into Dane Canyon in the East Clear Creek watershed.

No reports were received regarding the Bill Williams River basin. No reports were received regarding the upper Gila River basin in New Mexico.

Within the Gila River basin work has been conducted for a variety of species.

It was a big year for Gila chub Gila intermedia. The species was proposed for listing as endangered with critical habitat on August 9, 2002. O’Donnell Creek, a tributary of the Babocomari River in southern Arizona was successfully renovated with antimycin in June 2002 to remove green sunfish Lepomis cyanellus. Gila chub and desert sucker Pantosteus clarki were restocked in August. Sabino Canyon, a Gila chub habitat was successfully renovated for green sunfish in 1999, reached critically low water levels in lower canyon pools in July 2002. Gila chub were salvaged and held at the Forest Service Ranger Station. A September 2002 survey of Turkey Creek, in the Babocomari River basin failed to find Gila chub, which have not been seen there since 1991, but other surveys confirmed continued existence of Gila chub at Williamson Valley Wash in the upper Verde basin and found new locations in two Verde mid-basin tributaries.

A status report for roundtail chub Gila robusta and headwater chub Gila nigra was completed and a final report issued in January 2002. That report finds that there are significant declines in both species and substantial threats to most of their habitat.

For spikedace Meda fulgida and loach minnow Tiaroga cobitis, a survey of Verde River tributaries specifically looking for loach minnow failed to find any remnant populations. Construction plans, site investigations, and planning documents are under way for a fish barrier on the lower Blue River in eastern Arizona. Construction is scheduled to begin in September 2003. The Blue River, which has been identified by the Forest Service for native fish restoration, supports loach minnow and several other native fishes and frogs, is critical habitat for spikedace, and historic habitat for Gila chub.

The recent appearance of Asian tapeworm Bothriocephalus acheilognathi in the Verde River has been documented during research that is ongoing on native and nonnative species interactions.

For longfin dace Agosia chrysogaster a repatriation stocking was conducted in Martinez Canyon, a tributary of the middle Gila River near Florence. An ongoing crayfish removal project is also taking place in Martinez Canyon by a couple of dedicated volunteers.

Stocking of razorback sucker Xyrauchen texanus into the Verde River continues. No successful recruitment has yet been documented from this 15-year program.

A new population of desert pupfish Cyprindon maculariuswas initiated in Lousy Canyon, a tributary of the Agua Fria River. That stocking occurred in October 2001 and appears to have been succesful.

The first sighting of Gila topminnow Poeciliopsis occidentalis since 1994 in Sonoita Creek above Patagonia Lake occurred in July 2002. At Sharp Spring on the upper Santa Cruz River, fall surveys found Gila topminnow to still persist, although only 1 topminnow was found to 397 mosquitofish Gambusia affinis. In the Redrock Canyon drainage near Patagonia, an additional exclosure to livestock grazing was built to restore Gila topminnow habitat in Oak Grove Canyon. Original exclosure plans included habitat below and above a barrier, with repopulation to occur naturally below the barrier from movement from the main canyon. Above the barrier, repopulation would require stocking. The exclosure as-built does not include any below-barrier habitat, thus substantially reducing recovery value. The Forest Service has declined to rebuild the exclosure.

For Apache trout Oncorhynchus apache a renovation project to remove nonnative trouts was conducted in October 2002 on Snake Creek on the Apache-Sitgreaves National Forest.

In the Rio Sonoyta basin, verbal reports indicate the Rio Sonoyta had very little water this summer. Apparently staff of the Pinacate Biosphere Preserve conducted a salvage operation for the Quitobaquito pupfish Cyprinodon eremus to hold pending better water conditions.

At Quitobaquito Springs, the fall survey of Quitobaquito pupfish showed that population to be doing well. In this year’s survey 2,100 individuals were sampled. The mean of this 10-year effort is 2,280 individuals. Water level is down at the pond, but not enough to cause concern. Of more concern is the increasingly heavy traffic of illegal immigration at Quitobaquito, where even the border fence walk-through has been crushed by vehicle traffic.

In the lower Colorado River itself, a number of efforts are ongoing.

Efforts to rear bonytail chub at Niland Fish Hatchery have been temporarily suspended due to lack of success and severe infestation of the nonnative parasitic anchor worm Lernea cyprinacea. Efforts are concentrated at Achii Hanyo Hatchery near Parker. Achii Hanyo success rates have been good and parasite problems have been negligible. As of August 13, 2002, 7,728 bonytail chub have been augmented into Lake Havasu. Ongoing stocking efforts have also placed 30,000 razorack sucker into Lake Havasu.

Giant salvinia Salvinia molesta continues to be present in the lower Colorado River and irrigation canals downstream of Blythe. Efforts to eradicate it have been limited.

Beal Lake along the lower Colorado, was treated with rotenone in December 2001 to remove a variety of nonnative fish. It was restocked with 10,000 razorback sucker in April 2002. Mosquitofish Gambusia affinis were recently discovered to have either survived the treatment or reinvaded from nearby waters. Another 40 acres, at the Imperial Duck Ponds, was renovated in October 2002. Restocking of razorbacks has not yet occurred, but 5,000 are planned.

Recent population census on Lake Mohave estimate a razorback sucker population of 3,000 to 4,000 fish. That is compared to the 6-figure estimates of 20-30 years ago.

Research continues in the Imperial Division of the lower Colorado on habitat selection and overlap between razorback sucker and flathead catfish. Razorback sucker have been found to use off-channel backwaters newly reconnected as part of restoration activities. Flathead catfish Pylodictus olivarus, on the other hand, have been found to inhabit main and side-channel habitats and rarely co-occur with razorback sucker. Collection of razorback larvae in Senator Wash has begun with a purpose of quantifying reproduction, determining if it has led to recruitment, and how predation affects that particular area.

Gizzard shad Dorosoma cepediianum have now been confirmed as an established population in Lake Powell. This nonnative species was introduced as a contaminant in a shipment of sport fish from Inks Dam National Fish Hatchery to an upstream site on the Navajo Indian Reservation.

The USGS Branch of Biological Survey Fish Control Lab in LaCrosse, Wisconsin has undertaken a major study, through Central Arizona Project mitigation funding, to research and develop innovative techniques and integrated management for nonnative fish control in the Gila basin.

The distribution and recapture rate of approximately 2,000 subadult/adult razorback sucker (>250 mm) stocked directly into the river between 1997 and 2001 were compared with fish that were stocked as age-1 fingerlings (~ 100 mm) in a natural wetland in the spring of 1999 and accessed the Green River the following spring (approximately 1,100 fish in excess of 300 mm). The entire reach of the Green River between Split Mountain Canyon (rkm 352) and the confluence with the Colorado River was sampled with electrofishing boats during the spring of 2001. Three complete passes were made. Despite the fewer fish accessing the river from the floodplain, nearly three times (74) as many acclimated fish (i.e., floodplain stocked fish) were recaptured than those stocked into the river directly from the hatchery (29). Despite the differences in apparent capture rates the distribution of fish downstream from the stocking area was approximately equal between the two groups. As expected, the majority of post-stocking movement occurred downstream of the stocking site.

Larval razorback sucker were stocked into two 0.1 hectare pens with adult nonnative fishes. The numbers of nonnative fishes were similar to those observed during the first year of inundation following complete drying of the wetland. Each pen was stocked with a different density of larvae (~60,000 = low density, and 450,000 = high density). Larvae and nonnative adult fishes were stocked May and harvested in August. Zooplankton and water chemistry were monitored through out the study period. Following harvesting, 359 and 1,709 age-0 razorback sucker were harvested averaging 70mm and 58mm, respectively from the high and low density ponds. In addition to razorback sucker survival, large numbers of age-0 nonnative fishes were present in the study pens. Although survival was low, the potential for razorback sucker in offchannel wetlands following drought conditions offers management options that may improve natural recruitment.

During the study, two significant flood events impacted the San Marcos River and three affected the Comal River; these events resulted in significant short-term reductions in vegetation coverage and density. In both rivers, the vegetation types that provide the greatest habitat for fountain darters were generally the most significantly impacted; however, the impact to fountain darters differed between rivers. In the San Marcos River, estimates of fountain darter abundance decreased in the two reaches after each event. In the Comal system, estimates of fountain darter abundance did not differ dramatically before and after flooding in most instances. This suggests that fountain darters in the Comal River may have a greater “buffering” capacity to flooding effects than populations in the San Marcos River. One significant factor is the substantial area in the impounded headwaters of the Comal River (Landa Lake) compared to the remaining portion of the range in that system. Fountain darters are numerous in this habitat and it was virtually unimpacted from intense flooding. There is a similar protected pool in the headwaters of the San Marcos River (Spring Lake) which was not sampled using the same methods, but which visually appeared unimpacted following flooding. Snorkeling has shown that fountain darter densities are extremely high in Spring Lake, however, the lake constitutes a much smaller portion of the fountain darter range in the San Marcos River than Landa Lake in the Comal River. Recovery of vegetation following each flood event was rapid and suggests that flushing flows followed by a recovery period does not effectively reduce fountain darter habitat, and may stimulate growth and increase overall habitat availability.

Norogachi se localiza en la Sierra Madre Occidental, por su posicion geografica contiene elementos nearticos y neotropicales, que se conjugan con una topografia muy accidentada que va desde la zona desertica hasta el bosque de pino-encino, con elevaciones entre 200 y 3,000 msnm. Estos factores dan como resultado una diversidad biológica con características unicas, especialmente en los dos principales sistemas hidricos de la region: el rio Fuerte y el rio Conchos. Paradojicamente, esta es una de las regiones menos estudiadas del pais desde el punto de vista biologico, no obstante que la dinamica economica del area ha causado altos niveles de deterioro ambiental, al igual que el cambio climatico caracterizado por largas sequias. Con el proposito de hacer un reconocimiento de la diversidad de la ictiofauna, dentro de esta region prioritaria terrestre y dulceacuicola, se desarrolla un inventario por medio de un proyecto con la CONABIO, en el cual se han realizado recolectas y se trabaja en la revision critica de las bases de datos de las colecciones, donde se ha depositado material ictico de la region. Hasta el momento se tienen como resultados, la presencia de 14 familias, 28 géneros y 46 especies. Destacan por su abundancia las familias Cyprinidae con 15 especies, Poeciliidae con ocho e Ictaluridae con cinco. Ademas de los impactos reconocidos en la zona, se ha identificado la presencia de cinco especies introducidas.

Research activities for the 2001-2002 study year were conducted as lake elevation was declining to levels not encountered since the late 1970's. Reservoir elevations decreased 20 feet during the 2001-2002 study year, 31 feet since the beginning of the study in October 1996, and 55 feet since the highest elevation was reached during the study in October 1998. Numbers of larval razorback sucker captured at the Echo Bay and Las Vegas Bay study areas were similar to previous years; however, razorback sucker at Echo Bay utilized a new spawning area because of decreased lake levels. Spawning at Las Vegas Bay probably occurred at a location similar to previous years because of the increased depths at this location. No razorback sucker larvae were collected during spring sampling at the Colorado River inflow area.

Four sonic tagged, impoundment reared, razorback sucker were released at the Colorado River inflow area with the anticipation that these fish would lead us to wild spawning razorback sucker in the area. After nearly two months of tracking these tagged razorback sucker, they apparently left the area and were not relocated either up-river in the lower 40 miles of the Grand Canyon or down-lake in Gregg or Virgin Basin. The migration of these fish out of the Colorado River inflow area, combined with the fact that no razorback sucker larvae were found in the area this year, suggests that decreasing lake levels negatively affected spawning in this area and may have caused wild razorback sucker to move out of this vicinity.

An additional eighteen razorback sucker were aged during the 2001-2002 study year. These fish had ages ranging from six years, for a juvenile razorback sucker, to 35+ years for the oldest razorback sucker that we have aged during the study. Comparing the years spawned for all aged razorback sucker to historical Lake Mead water elevations provides some evidence that a combination of small annual lake level fluctuations, and larger multi-year changes in lake elevation may influence razorback sucker recruitment. The long tern lake level changes may promote the growth of litoral vegetation which could provide increased habitat for larval and juvenile razorback sucker, resulting in the limited recruitment documented in Lake Mead.

The distribution and recapture rate of approximately 2,000 subadult/adult razorback sucker (>250 mm) stocked directly into the river between 1997 and 2001 were compared with fish that were stocked as age-1 fingerlings (~ 100 mm) in a natural wetland in the spring of 1999 and accessed the Green River the following spring (approximately 1,100 fish in excess of 300 mm). The entire reach of the Green River between Split Mountain Canyon (rkm 352) and the confluence with the Colorado River was sampled with electrofishing boats during the spring of 2001. Three complete passes were made. Despite the fewer fish accessing the river from the floodplain, nearly three times (74) as many acclimated fish (i.e., floodplain stocked fish) were recaptured than those stocked into the river directly from the hatchery (29). Despite the differences in apparent capture rates the distribution of fish downstream from the stocking area was approximately equal between the two groups. As expected, the majority of post-stocking movement occurred downstream of the stocking site.

Larval razorback sucker were stocked into two 0.1 hectare pens with adult nonnative fishes. The numbers of nonnative fishes were similar to those observed during the first year of inundation following complete drying of the wetland. Each pen was stocked with a different density of larvae (~60,000 = low density, and 450,000 = high density). Larvae and nonnative adult fishes were stocked May and harvested in August. Zooplankton and water chemistry were monitored through out the study period. Following harvesting, 359 and 1,709 age-0 razorback sucker were harvested averaging 70mm and 58mm, respectively from the high and low density ponds. In addition to razorback sucker survival, large numbers of age-0 nonnative fishes were present in the study pens. Although survival was low, the potential for razorback sucker in offchannel wetlands following drought conditions offers management options that may improve natural recruitment.

A proposal to remove trout populations from the Sixth and Seventh lake complex to benefit native fauna was incorporated into a California Department of Fish and Game resurce management plan for the Big Pine Creek Basin and was accomplished using only intensive gill netting and electrofishing techniques. Approximately 10,000 trout were removed from 1999 through 2001. During this time amphibian numbers increased dramatically, and successful Rana muscosa reproduction was documented in both Sixth and Seventh lakes in 2002.

All three reaches represented distinct fish communities with different factors most likely affecting each reach. The San Acacia Reach fish community was most distinct, with highest Rio Grande silvery minnow densities. Red shiner, Cyprinella lutrensis, was also abundant in this reach, accounting for 23.7% of fish collected. Isleta Reach had the highest fish community stability with a majority of individuals represented by non-fluvial species red shiner, western mosquitofish, Gambusia affinis, and fathead minnow, Pimephales promelas. Angostura Reach had low fish community and flow regime stability and was dominated by white sucker, Catostomus commersoni. Non-fluvial species thrived in all three reaches while fluvial species such as Rio Grande silvery minnow, flathead chub, Platygobio gracilis, and longnose dace, Rhinichthys cataractae, declined.