ABSTRACT. Two Mexican trout taxa are formally described (Oncorhynchus chrysogaster, and O. mykiss nelsoni), but many other congeners have long been informally recognized as likely distinct. For more than two decades, the binational Truchas Mexicanas team searched for and collected trout broadly throughout the Sierra Madre Occidental of Sonora, Chihuahua, Sinaloa and Durango. That fieldwork documented that the native range of the genus extends to the Tropic of Cancer, or ~1000 km S of El Paso, Texas, and indicates that most of Mexico's trout exist as small, isolated populations with very restricted ranges. Genetic studies of Truchas Mexicana's specimens demonstrated that the many distinctive lineages found in Mexico are at least as divergent from one another as are their much more thoroughly-studied relatives in the O. mykiss complex in the Western U.S.A. When an opportunity presented itself to list the many still undescribed Mexican forms in the IUCN Red List, as part of a large project to assess the conservation status of the entire Mexican freshwater fish fauna, the authors rapidly compiled the necessary documentation and submitted the required proposal. Once the proposal was accepted, we then worked with IUCN staff to finalize formal conservation assessments that should be published in the Red List about 1 month after this presentation is given at the 2019 meeting. We hope that this official listing of these 12 mostly undescribed Mexican endemic species, with 3 determined to be Critically Endangered (CR), 5 Endangered (EN), 3 Near Threatened (NT), and one Data Deficient (DD), will call attention to this important biodiversity asset and open doors for much-needed financial support for the conservation actions that are so desperately needed. Meanwhile, work continues on the morphologically difficult diagnoses of the new species and their descriptions.

ABSTRACT. We performed experiments in desert streams to evaluate the efficacy of environmental DNA (eDNA) sampling for two rare minnows: Spikedace, Meda fulgida, and Loach Minnow, Rhinichthys cobitis. We compared detection sensitivity of eDNA assays to traditional sampling methods (electrofishing and seining) by using both techniques at 33 sites in 7 streams. We used caged-fish experiments to estimate eDNA production rates, persistence, and travel distances, and to estimate relationships between fish density, biomass and eDNA quantity. Loach Minnow were detected at 22 sites by both eDNA and traditional sampling, were not detected by either technique at 7 sites, and detected only by eDNA at 4 sites. Spikedace were detected with both techniques at 15 sites, not detected by either technique at 8 sites, and were detected only by eDNA at 7 sites. In the Verde River and Wet Beaver Creek, both species’ eDNA was detected downstream of caged fish out to our maximum sampling distance of 500 m. Estimated eDNA production rates were greater for Spikedace than for Loach Minnow, although more Spikedace were used. Production rates for both species were greater in the Verde River than in Wet Beaver Creek. Persistence of eDNA did not differ among species, but was greater in Wet Beaver Creek than in the Verde River. In density experiments, the amount of Spikedace eDNA was positively related to the density and biomass of caged Spikedace, but the relationship differed between streams. We conclude that eDNA surveys are more sensitive than traditional methods for detecting rare minnows in desert streams. With the sensitivity to detect even a single desert fish in a 100 m reach, managers will be able to more effectively identify habitat occupied by threatened or endangered desert fish, even if a population is in decline.

ABSTRACT. The Razorback Sucker, Xyrauchen texanus, and Flannelmouth Sucker, Castostomus latipinnis, are two fish native to the Colorado River basin. Currently within the Grand Canyon, Flannelmouth Suckers are abundant while Razorbacks remain extremely rare. Flannelmouth Suckers are found in abundance throughout the flowing waters of the Colorado River, while Razorback Suckers are generally found in the still or slow moving waters of Lake Powell, Lake Mead, and their inflows. Hybridization between these species occurs in the wild, however little is known concerning physiological differences between them and their hybrids. We investigated the differences in critical swim speed of purebred and hybrids of these species. A fish’s critical swimming velocity is a measure of its sustained swimming ability, not its maximum sprint speed. Determining the critical swimming speed of these species may illuminate how water velocity affect habitat constraints of these species, and increase our understanding of future repatriation challenges for the Razorback Sucker. Flannelmouth Suckers had a higher critical swim speed than Razorback Suckers, with hybrids intermediate. The critical swim speed results of these purebred catastomid species are consistent with general flow conditions of these habitat types where they are commonly found. The slower critical swim speed of Razorback Suckers could indicate challenges to repatriation throughout the Colorado River basin. Disparities in critical swim speed may be linked to physiological differences of the two species. Wolters (2017) did not see significant differences in body shape of Razorback and Flannelmouth Suckers and their hybrids up to 140 mm in length, but differences in behavioral and/ or metabolic performance have not been explored. Both hybrid types resulted in critical swim speeds between those of their parental stocks. The parental combination had significant effects, with swimming ability most consistent with their paternal species.

ABSTRACT. The Endangered Species Act (ESA) has been a critical tool to protect desert fishes since its passage in 1973, providing badly needed protections not only for fishes' habitats but also for the water sources those habitats rely on.

The threats to desert fishes from habitat degradation and groundwater overdraft persist, and the Center for Biological Diversity is currently using the ESA to pursue protections for numerous species. Three will be highlighted here.

The Moapa dace, Moapa coriacea, is threatened by groundwater overdraft in the Upper Muddy River spring complex in Clark County, Nevada. A complex legal battle over water use in the area which has played out administratively and in the courts for decades may be coming to a denouement. Unlike the Devils Hole pupfish, the dace does not have senior water rights, so this is a test case for the power of the ESA to protect these species on its own. The White River springfish, Crenichthys baileyi baileyi, is threatened with overuse by bathers in the thermal spring in Lincoln County, Nevada that it calls home. The protections it has under the Endangered Species Act should guard against this sort of degradation of its habitat. Finally, the Amargosa Canyon population of Nevada speckled dace, Rhinichthys osculus nevadensis, in Inyo and San Bernardino Counties, California, is threatened by groundwater overdraft in the regional carbonate aquifer which feeds the springs that form its habitat. Distinct Population Segment (DPS) status under the Endangered Species Act will be sought to protect the water that this species relies upon.

Each case poses significant questions about the reach and power of the ESA to protect desert fishes, and in each case, the fate of a species may hang in the balance.

ABSTRACT. The Razorback Sucker, Xyrauchen texanus, is an endangered endemic fish of the Colorado River basin. Recovery efforts include nonnative fish removals, habitat improvements, and population augmentation. All populations are still augmented by stocking except for the Lake Mead population on the Arizona-Nevada border and the Colorado River in Grand Canyon, Arizona. Adult and larval Razorback Suckers have been detected in the Colorado River within the Grand Canyon, however recruitment has yet to be documented. The Colorado River in Grand Canyon is largely dominated by the Flannelmouth Sucker, Catostomus latipinnis, another native sucker species. We hypothesized that Razorback Sucker recruitment may be negatively affected by competition with Flannelmouth Sucker. To test this hypothesis, we conducted a competition experiment with young of year fish at different temperatures and feed levels. We had four replicates of six different treatments: Flannelmouths at high and low feed, Razorbacks at high and low feed, and both Flannelmouths and Razorbacks at high and low feed. The experiment was conducted in two phases, each eight weeks in length. The cold phase (15 C) was first followed by the warm phase (20 C) with a one week acclimation period between phases. In the experimental treatment (Flannelmouths and Razorbacks together at low food) the Razorbacks gained weight at 15 C while the Flannelmouths lost weight. We did not see this pattern at 20 C. This preliminary result suggests that the presence of Flannelmouth Sucker may not be negatively affecting Razorback Sucker recruitment (at 15 C), or that limitations on Razorback recruitment within the Grand Canyon are occurring before they reach 30mm total length in the wild.

ABSTRACT. Opportunities for multi-species native fish restoration efforts are sparse in the desert southwest and such efforts are not always successful. Native fish restoration efforts are often impeded by biotic factors that can potentially be controlled (e.g., presence of nonnative fishes), but equally important are the abiotic factors that cannot be controlled (e.g., annual discharge and flow regime). The Blue River native fish restoration project began in 2009 with the goal of increasing the abundance of existing Loach Minnow, Rhinichthys cobitis, and establishing Spikedace, Meda fulgida, and Roundtail Chub, Gila robusta. The project involved several steps including the completion of a fish barrier to exclude nonnative fish, removal of nonnative piscivores in the lower portion of the river above the barrier, stocking of native fishes, and annual monitoring. The fish community of the Blue River experienced a significant shift from roughly equal proportions of native and nonnative fish in 2012 to an exclusively native fish community dominated by the three focal species in 2018. Nonnative piscivore removal efforts were successful as Channel Catfish, Ictalurus punctatus, were last captured in 2013 and Green Sunfish, Lepomis cyanellus, in 2016. We evaluated whether relative abundance of native fish was related to a number of factors including: time since stocking, relative abundance of nonnative fishes, and several discharge metrics using generalized linear modeling. Time since stocking best explained the relative abundance of the three focal species, but discharge may also play a role. Relative abundance of pre-existing native fishes was most influenced by relative abundance of nonnative predators. The distribution of the three focal species within the mainstem increased rapidly from 2012 to 2018 and Roundtail Chub were detected several miles upstream in a major tributary in 2019. A comprehensive approach to native fish restoration resulted in the eradication of nonnative fishes and the establishment of robust populations of sensitive native species in the lower Blue River. By evaluating factors that contributed to successful establishment of focal species, we can implement future restoration efforts with a more informed approach, ultimately resulting in additional successful restoration efforts.

ABSTRACT. Red Swamp Crayfish, Procrambus clarkii, invaded the Simone Pond of the Thousand Palms Oasis Preserve in the Coachella Valley, California in the 1950s; subsequently, their destructive habits have led to the extirpation of the endangered Desert Pupfish Cyprinodon macularius. Scientific literature has demonstrated that eradicating P. clarkii is extremely difficult (Hyatt 2004). The only successful attempts have come from plans that combine multiple techniques that work synergistically (Girardet et al. 2012). Therefore, a multi-faceted eradication plan was developed and implemented to eradicate P. clarkii from the Simone Pond. This plan included physical (draining the pond, implementing vigorous trapping, and erecting barriers), electrical (utilizing an electrofishing backpack), and chemical (applying pyrethroids, a synthetic version of pyrethrin that degrades swiftly and does not bioaccumulate) to achieve complete eradication of P. clarkii. These combined efforts proved effective in eradicating this invasive species from the Simone Pond—no crayfish have been observed or captured in traps since June 26, 2019. Currently, biotic data (benthic macroinvertebrate sampling, planktonic macroinvertebrate sampling, and submerged aquatic vegetation assessment) and abiotic data (water quality measurements, water level measurements, and pesticide concentration measurements) are being collected to ensure the pond meets environmental standards for the Desert Pupfish. Desert Pupfish are projected to be reintroduced into Simone Pond in June 2020.

ABSTRACT. Fishes of the Colorado River Basin have suffered declines in abundance and genetic diversity attributable to large-scale river flow regulation that began in the early 1900s. Subsequent proliferation of non-native predators led to system-wide recruitment failures of Razorback Sucker, Xyrauchen texanus, and Bonytail, Gila elegans. A conservation plan to rear fishes in predator-free backwater habitats was proposed to facilitate recruitment. Genetic factors were considered, but uncertainties remained regarding sources of variance in reproductive success (VRS) that spoke to generality and efficacy of the backwater rearing strategy. In this study we used parent-offspring genotyping to evaluate VRS in Razorback Sucker and Bonytail. Individual VRS was higher in Razorback Sucker than Bonytail in a manner consistent with species-specific differences in life history, but neither species exhibited VRS in excess of Poisson expectation when parental contribution was greater than 50% in a given backwater. However, we observed ‘all or nothing’ recruitment events across backwaters that were presumably tied to local differences in water quality and predator regimes. Thus, as mean quality and stability of selected backwaters increases and variance in quality among backwaters decreases, fewer backwaters will be required to implement the conservation plan at proscribed levels of genetic diversity.

ABSTRACT. Restoration efforts to benefit the conservation of native fish through securing native fish from nonnatives and increasing distribution of native fish in the desert southwest has had limited success due to the establishment of nonnative and piscivorous species. During 2016, the Arizona Game and Fish Department began a project in the Red Tank Draw Drainage to remove nonnative piscivorous fish and to expand the range of native species within the drainage. Red Tank Draw is a tributary to Wet Beaver Creek on the Coconino National Forest that supports an assemblage of native fish species including Roundtail Chub, Gila robusta, Longfin Dace, Agosia chrysogaster, Desert Sucker, Catostomus clarki, and Sonora Sucker, Catostomus insignis. Red Tank Draw also supports a compliment of nonnative fishes including Green Sunfish, Lepomis cyanellus, Black Bullhead, Ameiurus melas, and Fathead Minnow, Pimephales promelas. In 2016 the Department began mechanical removal efforts of nonnative fish in Red Tank Draw. After limited initial success a comprehensive survey of the drainage (including two tributaries, Rarick Canyon and Mullican Canyon) and several stock tanks within the drainage was completed in 2017. Green Sunfish and Black Bullhead were detected in Mullican Place Tank and in downstream tinajas in the Mullican Canyon drainage. Fathead Minnow were detected in two tanks and downstream tinajas in the Rarick Canyon drainage in 2017 and Black Bullhead were detected in downstream tinajas in 2018. Mechanical removal of Black Bullhead in Rarick Canyon began in April, 2019 with eradication achieved by August, 2019 after the removal of 14 Bullhead. Removal efforts in Red Tank Draw have been ongoing since the project began in 2016. The size class structure of Green Sunfish has shifted to mostly smaller fish, and fewer Black Bullhead have been detected. A comprehensive approach to the Red Tank Draw drainage allowed for the suppression or eradication of nonnative fishes and will hopefully allow for an increase in distribution of native species. Considering the importance of upstream sources of nonnative fishes and opportunities for creating refugia for native species resulted in a successful approach for native fish conservation and will help inform future efforts.

ABSTRACT. Low probabilities of capture (<0.05), based only on physical recaptures of tagged fish, have hindered the precise estimation of survival rates for endangered Razorback Sucker, Xyrauchen texanus, in the upper Colorado River basin (UCRB). Because those populations are maintained by stocking of hatchery-reared individuals (N = 416,004 cumulatively through 2017), reliable evaluations of survival are essential to the species’ management. Since 2008, PIT tag detection antennas and ultrasonic receivers have been deployed throughout the UCRB, San Juan River Basin, and Colorado and San Juan river arms of Lake Powell to passively document tagged fish. Increased detections, along with physical captures from more intensive sampling, were used to determine if more robust estimates of survival were possible. Encounter records of 395,488 stocked Razorback Suckers from 1995 through 2017 were analyzed with the Barker model, in which passively-collected data are incorporated as “resight” events outside the physical sampling occasions. Annual capture probabilities remained low (mean: 0.05, range: 0.01–0.09), as in previous studies. Since antenna deployment began, resight probabilities increased from 0 to a high of 0.13 in 2017. Importantly, the empirical rate of physical recaptures for the entire 23-year study period was 3.9%, while rate of detections from antennas was nearly half that (1.8%) but almost entirely from just the most recent five years of antenna use, < 25% of the study period. Analyses supported previous findings that survival through the first year post-stocking was lower than subsequent years, first-year survival for fish stocked during summer (mean: 0.06, range: <0.01–0.12) was lower than other seasons (mean: 0.20, range: 0.01–0.39), and first-year survival of fish stocked in the Green River subbasin (mean: 0.27, range: 0.02–0.80) was higher than the Colorado River subbasin (mean: 0.12, range: <0.01–0.59). Both seasonal and subbasin survival rate estimates through the first year were higher and more precise than those from our previous studies using only records from 1995–2006 and 2004–2008. This analysis showed survival after the first year post-stocking increased to 0.83 (CV < 1%) and was higher and more precise than in 1995–2006 (0.75, CV = 4%). Incorporating passive detection data with physical recaptures provided more robust survival rate estimates, which are useful to evaluate hatchery stocking practices and recovery status of populations. Passive detections may also improve estimation of population parameters for other PIT-tagged fishes in large river systems where capture probabilities are low.

ABSTRACT. Captive propagation is vital to recovery and management of many imperiled fishes. With fewer than 200 fish restricted to a single pool in the Mojave Desert, the federally endangered Devils Hole Pupfish, Cyprinodon diabolis, seems a prime candidate for captive propagation. However, despite decades of attempts, propagation in aquaria has never been fully successful. While refuge populations had some success, ultimately all ended in failure. Since 2013, the Ash Meadows Fish Conservation Facility (AMFCF) has maintained a backup population of Devils Hole Pupfish. To establish the population, eggs were recovered from Devils Hole and brought to the lab at AMFCF for rearing and culturing. Herein, we discuss recent advances in captive breeding of the Devils Hole pupfish. Specifically, we highlight advances that resulted in fertilized eggs being collected from the refuge population and breeding trials in aquaria that produced fertilized eggs. Finally, we present results of a comparative analysis of eggs collected from the three sources (wild, refuge tank and lab aquaria) comparing egg production, hatching success and survival to adulthood. Understanding differences in reproduction between wild and captive fish is critical for recovery of the Devils Hole Pupfish and will help inform management of this and other species.

ABSTRACT. Yaqui Catfish, Ictalurus pricei, is an understudied species with limited data on their distribution, environment, or habitat use. Native to southwest United States, and northwest Mexico, Yaqui Catfish populations are declining, causing the species to be listed as threatened in the United States, and specially protected in Mexico. Water over-allocation, habitat degradation, invasive species introductions, and hybridization with non-native Channel Catfish, Ictalurus punctatus, have caused the declining populations in Mexico. To help better focus conservation efforts, as well as define important habitat for Yaqui Catfish we modeled the potential distribution using species distribution model MaxEnt, a machine learning program, in the Yaqui River Basin, a basin found in both the US and Mexico. Limited biologically relevant geospatial environmental data in Mexico caused us to model at a landscape scale, allowing us to determine factors that may affect the entire population. Some variables we used were elevation, landcover, temperature, precipitation, and stream order. Response curves from the model indicated relationships with stream order, riparian shrub and slope. Model results also estimated habitat suitability for Yaqui Catfish in 78% of the Yaqui Basin. Evaluations of the model suggest it was predictive as well as discriminative.

ABSTRACT. In May 2018, 290 adult Pahrump Poolfish, Empetrichthys latos, and 100 juvenile Relict Leopard Frogs, Rana onca, were released into two constructed ponds at the Las Vegas Springs Preserve in Las Vegas, Nevada. These introductions mark the first time in over sixty years that native fish and frogs have occupied the site of the historic Las Vegas springs. Once a lush oasis within an arid Mojave Desert landscape, the Las Vegas spring complex ceased flowing prior to 1962 due to increasing groundwater usage. The loss of this spring complex led to the extinction of the endemic Las Vegas Dace, Rhinichthys deaconi, around 1957. Reduced spring flows along with habitat alteration also led to the extirpation of the Vegas Valley Leopard Frog, Rana fisheri, within the Las Vegas Valley by the late 1940’s. In the following decades, the site of the Las Vegas spring complex existed solely as a well field, providing water for the growing Las Vegas community. In 1997, however, the Las Vegas Valley Water District Board of Directors approved a plan to develop a 180-acre preserve to protect and manage the natural, cultural, and water resources of the site. The Springs Preserve opened in June 2007, and by 2010 plans were made to restore some surface water habitat within the original spring complex channels. The imperiled Relict Leopard Frog and the federally endangered Pahrump Poolfish were identified as candidates to inhabit these ponds. Both species are native to Nevada and need additional refuge populations and would fill the niches of the extirpated species. The initial two ponds were completed in early 2018 and by late May, Pahrump Poolfish from an existing refuge population and captive reared Relict Leopard Frogs representing two natural populations were introduced. Surveys in October 2018 documented 4 large adult Relict Leopard Frogs (1 male and 3 females) and provided a population estimate of 386 (95% CI 278-605) Pahrump Poolfish. Several cases of Fall/Winter mortality of the Pahrump Poolfish were documented. In Spring 2019, 101 large Relict Leopard Frog tadpoles and 111 juvenile frogs were released in the ponds. A nocturnal survey in March 2019 documented 2 large adult frogs including a calling male. Numerous small Relict Leopard Frog tadpoles were observed in late April 2019, which demonstrated natural recruitment. Larval Pahrump Poolfish were observed in May 2019, and a mark-recapture survey in June provided an estimate of 173 (95% CI 131-232) adult Poolfish between the two ponds. A visual encounter survey of Relict Leopard Frogs in August 2019 documented 195 juveniles and 4 small adults. In September 2019, a survey of Pahrump Poolfish documented 130 individuals including fish under 35 mm in length, which represented new recruitment. An additional eight ponds at the Springs Preserve may eventually hold Pahrump Poolfish and Relict Leopard Frogs.

ABSTRACT. The lower Colorado River Basin encompasses an area that spans from Lee’s Ferry, Arizona, approximately 15 river miles below Glen Canyon Dam (Lake Powell), to the Gulf of California (Sea of Cortez), Mexico. Historically, the dynamic nature of river would have meandered across large flood plains, creating isolated pools, oxbow lakes, and backwater habitats, that were broken in small areas by when not bound by narrow canyons and high gradient reaches. This ecosystem was home to numerous species of fish, reptiles, plants, and invertebrates. However, in less than 100 years, a system of dams, diversions, levees, and canals has left this region as one of the most managed rivers in the world. Many scientists are currently working within the basin to better understand, conserve, and enhance endangered, threatened, and native fish populations. This report highlights some of the research, monitoring, and recovery efforts for fishes within the lower Colorado River Basin.

ABSTRACT. The Yaqui Catfish, Ictalurus pricei, is an endangered species (SEMARNAT, IUCN) due to the decline and loss of its populations in more than half of its historical distribution in Mexico and the United States. The main threat is the competition and hybridization with the Channel Catfish, I. punctatus. As part of the efforts for the conservation of the species, in 2019 began the creation of a reproductive stock in Rancho San Bernardino, Sonora, with 18 individuals morphologically similar to Yaqui Catfish collected in Arroyo Cajón Bonito, sub-basin of the Bavispe River to start the recovery of the species in Mexico. In this work, the specific identity of the catfishes captured, is being analyzed by means of the DNA barcode from the mitochondrial gene COXI, and the phylogenetic analysis of all individuals was performed with the COXI gene and the nuclear genes RAG1 and RAG2, with the objective of characterizing genetically the stock to ensure purity and reproductive success. So far 13 pure Yaqui Catfish, three Channel Catfish and two Ictalurus punctatus X pricei hybrids of the 18 initiators of the Arroyo Cajón Bonito in Sonora have been detected. This is the first genetic evidence of hybridization between these two species found in the wild in Sonora. We recommend including this information in the management of individuals in the reproductive stock in facilities of the Instituto de Acuacultura del Estado de Sonora and increase the evidence by using microsatellites to rule out possible genetic introgression.

ABSTRACT. The Moapa Warm Springs in Southern Nevada is a regional spring complex that forms the headwaters of the Muddy River. These thermal springs, and associated streams, are habitat for an endemic suite of thermophilic aquatic species that includes the federally-endangered Moapa Dace, Moapa coriacea. Currently, the Southern Nevada Water Authority (SNWA) and other stakeholders are undertaking recovery actions for the Moapa Dace and its habitat. These include construction of fish barriers, reduction in or removal of non-native and invasive species, riparian and aquatic habitat restoration, and development of an ecological model for the Moapa Dace. To facilitate recovery of the dace and other native species, SNWA purchased the 1,218-acre Warm Springs Ranch in September 2007 and designated it the Warm Springs Natural Area for conservation and environmental stewardship purposes.

In 2008, Moapa Dace numbers suddenly declined to a record low of 459 individuals. Working with the US Fish and Wildlife Service, Nevada Department of Wildlife (NDOW), and other stakeholders and researchers, SNWA is conducting stream restoration work and intensive habitat improvements to reverse the population’s decline. Following the February 2008 nadir, dace numbers improved somewhat but have yet to reach recovery levels of 6000 fish. Latest snorkel counts recorded 1317 Moapa Dace in August 2019. Since 2008, NDOW and SNWA have successfully treated the Upper Muddy River with rotenone to control the invasive and predatory Blue Tilapia, Oreochromis aureus. Furthermore, stream restoration and clearing of dense stands of invasive Tamarisk, Tamarix spp., and California Fan Palms, Washingtonia filifera, are facilitating the re-establishment of native riparian vegetation, providing prevention of future wildfires and continued improvement in Moapa Dace numbers.

In 2015, a removable fish barrier was opened that allows the dace access to its entire historical range. In 2018, additional habitat was acquired on the North Fork with a property purchase and that stream is currently being restored. In 2019, 59 Moapa Dace were translocated into the South Fork and those fish have successfully reproduced. Moapa Dace numbers are currently stable and work continues to improve dace habitat, improve stream connectivity, and to monitor for invasive species.

ABSTRACT. A long-standing objective of biogeography is to relate patterns of genetic diversity to historical and contemporary processes that influence the distribution of populations across a landscape. For some taxa, the role of human-mediated dispersal can confound the signal from natural processes and obscure our understanding of a species’ evolutionary history. The Longfin Dace, Agosia chrysogaster, is a small-bodied minnow native to the Upper Gila River basin in New Mexico. Accounts as early as the 1950’s proposed that the Longfin Dace was recently introduced into tributaries of the Mimbres River and the Rio Grande. Human-mediated dispersal was hypothesized as a mechanism for crossing the trans-continental divide, but recent molecular evidence suggests that headwater capture events may have mediated the east to west movement of other fish taxa (e.g., Pantosteus plebeius). Therefore, it is plausible that populations of the Longfin Dace found east of the trans- continental divide were established via a similar headwater capture event as P. plebeius as opposed to human-mediated dispersal. We sequenced a mitochondrial locus for 294 individuals collected across Arizona and New Mexico to examine range-wide patterns of historic population structure. Additionally, we assayed a panel of 9 microsatellite loci for 165 individuals collected in New Mexico to infer the mechanism of colonization across the trans-continental divide.

ABSTRACT. Freshwater ecosystems are undervalued and receive insufficient funding, political attention, and protection globally. In order to develop interest and funding for freshwater species conservation, the International Union for Conservation of Nature’s (IUCN) Freshwater Biodiversity Unit (FBU) is working to complete a globally comprehensive assessment of freshwater fishes by 2021. As part of this initiative, extinction risk of 536 species of Mexican freshwater fishes were evaluated against the IUCN Red List Categories and Criteria, representing the most comprehensive assessment of freshwater biodiversity in Mexico to date. The results of this highly collaborative assessment process reveal that 40% of all extant species assessed are threatened with extinction, and 18.5% are data deficient. The threats to freshwater biodiversity in Mexico are diverse, and threat is not evenly distributed across Mexico. These results can be used to help support the implementation of multilateral environmental agreements in Mexico, guide conservation planning and priority setting at the local and national levels, and will provide a baseline of conservation success in subsequent assessments of extinction risk. Recommended conservation actions include the promotion and development of an integrated Mexican freshwater fish conservation strategy, including directives to further study data deficient species, the planning and establishment of additional freshwater protected areas and environmental safeguards, establishment of species level conservation plans where necessary, identification of suitable candidate species for ex-situ conservation, and planned reevaluation of conservation status to develop a regional Red List Index.

ABSTRACT. Rock pools are important ecosystems providing rare sources of surface water in arid regions. Hydroperiod is one of the primary limiting factors for aquatic macroinvertebrates living in rock pools. Resident macroinvertebrates must complete their life cycles before pool drying, and may employ active or passive dispersal strategies to survive. Quantifying dispersal and functional feeding traits across rock pool macroinvertebrate communities in multiple regions could provide insight into how rock pool ecosystems will respond to shorter hydroperiods predicted by climate change models. We reviewed taxonomic data (26 species lists) from 24 published studies on rock pools in Africa, North America, and Australia, to assess the dispersal and feeding strategies of macroinvertebrates, and how ecosystem functions may change with shorter hydroperiods. On average, taxa lists were equally comprised of active dispersers and passive dispersers. Most active disperser taxa were predators (60%) and gatherers (33%). In contrast, passive disperser taxa were generally filterers (39%), gatherers (29%), and scrapers (21%). Climate change may reduce rock pool hydroperiods, which could reduce habitat availability for passive dispersers with weak overland dispersal abilities. If passive disperser populations decrease, their associated ecosystem functions, such as fine organic matter processing, could be disrupted. These results provide a foundation for future work investigating changes in rock pool ecosystem function due to altered hydroperiods.

ABSTRACT. The Gray Redhorse, Moxostoma congestum, is a species native to the Gulf Coastal drainages of central and west Texas, the Rio Grande and Pecos River in Texas and New Mexico, and Mexican tributaries to the Rio Grande downstream of the Big Bend region. Gray Redhorse are listed in New Mexico as endangered and the American Fisheries Society Endangered Species Committee considers this species to be threatened [Jelks et al., 2008, Fisheries 33(8):372-407]. By 2008, only two populations were known to persist in New Mexico. Fish kills resulting from blooms of toxic golden algae, Prymnesium parvum, were largely responsible for this extirpation event. Following an extensive survey effort, the New Mexico Department of Game and Fish, in cooperation with the Bureau of Land Management, initiated a reintroduction of Gray Redhorse to the Delaware River in 2012. Multiple years of habitat restoration of the Delaware River provided suitable conditions for repatriation of this species of conservation concern. Forty-four adult redhorse were captured in the Black River and translocated to the Delaware River between 2012 and 2018. These individuals were introduced to a site containing a translocated population of Texas Hornshell, Popenaias popeii. As Gray Redhorse serve as a primary host for the glochidia stage of the mussel, repopulating the Delaware River with this species is equally important to the long-term viability of Texas Hornshell. Annual monitoring of the restoration site has occurred since 2013 and multiple young-of-year Gray Redhorse were detected between 2016 and 2018. The creation of a third population reduces the risk of extirpation of Gray Redhorse and Texas Hornshell in New Mexico. Future priorities for this recovery effort include improving fish passage on the Delaware River and identifying additional restoration sites in New Mexico.

ABSTRACT. Notropis stramineus (Cope, 1865), the Sand Shiner, is a small minnow with an expansive range. It is distributed across much of the North American continent to the east of the Continental Divide, from northern Mexico (Rio San Juan and Rio Salado) to southern Canada (upper St. Lawrence River and Great Lakes drainage to the east and the Red-Assiniboine River system to the west), spanning regions commonly recognized as phylogeographic barriers. Within the southwestern U.S., N. stramineus is found in Oklahoma, New Mexico and Texas, where it is distributed in most river systems including the Rio Grande system (Pecos and Devils rivers). Despite early taxonomic work, including the recognition of two subspecies (N. s. stramineus and N. s. missuriensis), the Sand Shiner continues to be recognized as a single widespread species. To test the hypothesis that the widespread N. stramineus represents a single species, we gathered one mitochondrial gene (Cytb) and two nuclear loci (S7 and RAG1) representing the breadth of the range. Preliminary analysis of this data suggests that N. stramineus represents several genetically distinct and geographically isolated lineages. Additionally, the current subspecies designations may not accurately represent the true evolutionary history of this species complex.

ABSTRACT. Westwater Canyon on the Colorado River contains one of the five remaining populations of the endangered Humpback Chub, Gila cypha, in the Upper Colorado River Basin. Westwater Canyon also contains a large population of Roundtail Chub, Gila robusta, which are listed as a species of concern throughout their range. Recovery goals identified by the Upper Colorado Recovery and Implementation Program require maintaining several populations of Humpback Chub within the Upper Colorado River Basin. Monitoring efforts are essential to evaluate the population of Humpback Chub in Westwater Canyon and meet the recovery goals. Trammel nets, electrofishing gear, and submersible antennas were used to sample humpback and Roundtail Chubs in Westwater Canyon in 2016 and 2017. Important metrics including catch rates, size structure, and population size were calculated for Humpback and Roundtail Chub. Catch rates of Humpback Chub in 2016 and 2017 were 0.3 and 0.5 fish/hr, respectively. Catch rates of Roundtail Chub in 2016 and 2017 were 1.37 and 0.98 fish/hr, respectively. The population size of Humpback Chub in 2016 and 2017 were estimated at 2,002 (95% CI 1118-2886, SE=430, CV=0.23) and 3,656 (95% CI 1,177-6,133, SE=1,097, CV=0.30), respectively. The population size of Roundtail Chub in 2016 and 2017 were estimated at 7,916 (95% CI 6,320-9,512, SE=811, CV=0.10) and 11,300 (95% CI 8,055-14,545, SE=1,645, CV=0.15), respectively. In this presentation, I will describe recent monitoring activities of Humpback and Roundtail Chub in the context of historical data for the Westwater population.

ABSTRACT. Desert fishes in the American southwest are vulnerable to anthropogenic landscape alterations. Nearly 90% of pupfish (family Cyprinodontidae; 38 of 43 species) are listed as imperiled and many persist within freshwater protected areas (FPA). Pupfish population assessments within FPA are infrequent, in part, because of inconsistencies and few comparisons among methods. We developed density estimates for the Comanche Springs Pupfish, Cyprinodon elegans, using mark-recapture and unmarked individuals observed through visual count (VC) and minnow trap (MT) surveys at Balmorhea State Park (BSP), Texas, USA. During Spring 2019, we collected 1,328 C. elegans during three repeated VC and MT surveys at 40 locations within BSP. We fit a Schnabel estimator to the mark-recapture data and N-mixture models to VC and MT count data and assess the influence of habitat covariates and spatial autocorrelation using Akaike’s information criterion. We found N-mixture model estimates were generally greater than mark-recapture model estimates, though models agreed in some habitats. We also found differences in density estimates from VC versus MT methods, including higher densities from MT in shallow water and VC in deep water. Best-fit models included habitat covariates such as depth, water temperature, and fine sediments, though spatial autocorrelation variables were the strongest predictors. We conclude that N-mixture models fit to unmarked individuals from VC and MT methods include trade-offs in their performance depending on habitats surveyed, and that spatial contexts matter. Monitoring other fishes inhabiting other FPA using the methods described here could provide consistent and repeatable abundance indices to benefit conservation biology.

ABSTRACT. The threat that invasive fish species pose to native aquatic species is substantial. In McGee Wash, a tributary to Trout Creek in the Bill Williams River drainage, Green Sunfish, Lepomis cyanellus, pose a threat to the native aquatic species present. In 2017, the Arizona Game and Fish Department began a project to remove non-native Green Sunfish from McGee Wash to eliminate the threat to native aquatic species. McGee Wash has a 1.5 km stretch of perennial water that hosts an assemblage of native aquatic species including Roundtail Chub, Gila robusta, Desert Sucker, Catostomus clarkii, Sonora Sucker, Catostomus insignis, Lowland Leopard Frogs, Lithobates yavapaiensis, and Sonora Mud Turtles, Kinosternon sonoriense. Removal efforts have consisted of monthly single pass backpack electrofishing and minnow traps to collect and remove all Green Sunfish. Initially Green Sunfish inhabited the entire perennial reach, and various age classes were found throughout the reach. After 33 mechanical removal trips the fish assemblage in McGee Wash has changed from a non-native dominated fish assemblage to a native fish dominated assemblage and few Green Sunfish have been detected. Mechanical removals will continue until Green Sunfish are eradicated from the reach. However, suppression of Green Sunfish has allowed the native aquatic species to repopulate the stream and distribute throughout the perennial reach.

ABSTRACT. The endangered Sonoyta Mud Turtle, Kinosternon sonoriense longifemorale, is a subspecies endemic to a small portion of the Sonoyta River in Sonora, Mexico and Quitobaquito Springs in Arizona. Human development in the region and economic activities, such as agriculture, livestock production and mining, have caused overdraft of the Sonoyta aquifer and reduced flow in the river. This situation has led to a decrease in the habitat available for the Sonoyta mud turtle. Localities with Sonoyta Mud Turtles have been reduced from seven sites in 2003 to three natural and two transplanted sites in 2019, one of which is a sewage treatment lagoon. The largest natural population occurs in the Agua Dulce reach of the Sonoyta River, a roughly 2 km long reach that contracts to only pools during the dry season. From 2017-2019, we estimated the mud turtle population size of the Agua Dulce reach using the capture-recapture sampling method. Additionally, we quantified mud turtle movements based on ten individuals (5 males and 5 females) that were radio-tagged in 2017 and 2018. Thus, we estimated mud turtle seasonal home ranges by calculating the Minimum Convex Polygon (MCP) based on all locations where tagged individuals were recorded. Using the Schumacher-Eschmeyer model, we estimated a population size of 209 turtles, with a 95% confidence interval. Radio-tagged individuals had a mean seasonal home range size of 0.09 ha and travel paths with a mean length of 173 m. Females had larger mean seasonal home ranges than males (0.12 ha vs 0.04 ha) and longer mean travel paths (239 m vs 91 m). Despite their ability to survive in degraded wetlands and tolerate periodic loss of flow in the river, decreasing dry season habitat poses a serious conservation concern. If wetted areas keep decreasing in the study site due to water withdrawals and a change in the precipitation requency, then the Sonoyta River may not support a healthy turtle population in the future.

ABSTRACT. A previous study in Northern Utah suggested there is competition between large predatory Perlid stoneflies and trout (salmonidae). We examined stonefly abundance in two small Wasatch Front creeks, expecting fewer perlids to co-occur with trout. Each creek system had a trout (lower Strongs Creek and Steed Creek) and troutless (upper Strongs Creek and Davis Creek) reach. We sampled 24 pools with trout and 27 troutless pools. We electrofished each pool to confirm the presence or absence of trout and mini-Surber sampled for two common families of stoneflies: Chloroperlidae (Sweltsa) and Perlidae (Hesperolperla, Eccoptura, Neoperla). Mean number of Perlidae per pool was lower in reaches with trout than without (Strongs Creek: 0.46 ± 0.22 SE with trout, 1.80 ± 0.51 SE troutless; Davis-Steed Creek: 0.00 ± 0.00 SE with trout versus 2.75 ± 1.12 SE troutless). This fit our prediction. The opposite trend was seen with the Chloroperlidae mean numbers (Strongs Creek: 0.85 ± 0.42 with trout versus 0.30 ± 0.15 SE troutless; Davis-Steed Creek: 6.08 ± 2.04 SE with trout versus 2.94 ± 0.77 SE troutless), but their abundance difference was not statistically significant. Competition or predation by trout may limit perlid abundance, whereas chloroperlids might not compete with or be preferred food for trout because they are much smaller than perlids.

ABSTRACT. Input and output subsides link aquatic and terrestrial ecosystems. Non-native trout occur at higher densities in streams where they replace native trout and can disrupt key ecosystem functions that cross ecosystem boundaries, such as aquatic-insect emergence. The increased biomass and behavioral differences of non-native trout can influence other aquatic predators such as predatory stoneflies (Perlidae) and water striders (Gerridae), as well as riparian predators such as spiders (Tetragnathidae). Our study sites were in six streams along the northern Wasatch Front, Utah. We hypothesized three streams with non-native rainbow trout would have fewer aquatic and riparian predators than three others with native Bonneville cutthroat trout. We found mean rainbow trout biomass (598.96 ± 277.2 SE mm/m^3 ) was higher than cutthroat trout biomass (202.09 ± 87.5 SE mm/m^3 ). Water strider densities were higher in cutthroat streams than in rainbow streams (1.07 ± 1.02 SE m^3, 0.18 ± 0.13 SE m^3, respectively), as were perlid stonefly densities (0.25 ± 0.14 SE m^3, 0.12 ± 0.05 SE m^3, respectively). In contrast, tetragnathid spider horizontal-web density was lower in cutthroat streams than in rainbow streams (1.53 ± 1.20 SE m^3, 3.07 ± 1.30 SE m^3, respectively). Differences in habitat could account for some of our findings. Rainbow streams were wider with higher aerial-wood and submerged-wood biomass. Aerial wood could provide web-building sites for tetragnathid spiders and submerged wood could elevate in-stream productivity. On the other hand, cutthroat streams were deeper and had larger substrates, possibly better habitat for perlid stoneflies. In any case, evidence suggests non-native rainbow trout do interact differently with other predators compared to native Bonneville cutthroat trout.

ABSTRACT. Studies of aquatic-riparian ecosystems suggest that trout (Salmonidae) can impact associated invertebrate predators, like aquatic larvae of perlid stoneflies, water-surface dwelling water striders (Gerridae), and riparian tetragnathid spiders. We studied 100 m reaches in seven small streams along the northern Wasatch Front (Weber and Davis counties, Utah). In each stream, we counted water striders, horizontal spider webs (characteristic of tetragnathids), and used kick nets to sample perlid larvae along 10 evenly spaced transects. We also measured wetted width and water depth. We made pebble counts every 0.2 m across transects and measured all submerged and aerial branches (stem width). We sampled trout through each reach with a backpack electrofisher and calculated habitat volume as median width x median depth x reach length to calculate biomass based on trout total length. We used Pearson correlations to explore potential relationships of depth, width, substrate, submerged branch, aerial branch, and trout biomass with the densities of water striders, spider webs, and perlid larvae. We found most significantly that water-strider and spider-web density were inversely correlated with depth and spider-web density was positively correlated with median width and with submerged-branch density. Interestingly, perlid density correlated positively with trout biomass. Overall, this suggests trout abundance is not necessarily the primary driver of abundance in other aquatic or riparian predatory invertebrates and that habitat features can be important. For instance, in streams with higher productivity, multiple predator populations might increase. Also, streams with greater width may have a higher diversity of habitats, with more opportunities for different predators.

ABSTRACT. Over 1,200 native freshwater fish species occur on the North American continent, composing the largest temperate, freshwater fish fauna on Earth. The importance of freshwater fishes in North American ecosystem function, their direct value economically and as providers of ecological services, and the increasing need to conserve this fauna cannot be over emphasized. In the last 30 years, major scientific advances have been made for these fishes across disciplines of systematics, genetics, physiology, behavior, ecology, and conservation. These advances, however, are marked by increased specialization and resulting fragmentation of knowledge about the diverse North American fish fauna. Our three-volume series is the first-ever published, fully-illustrated work synthesizing the diversity, natural history, ecology, and biology of 52 families of North American freshwater fishes (including several marine families with species occurring in fresh water). The coverage includes all of Canada, the coterminous United States, and Mexico (south to about the Isthmus of Tehuantepec). Chapter authors are synthesizing information on a set of standard topic areas for each family and our emphasis is on near-comprehensive synthesis of existing information on freshwater fishes in North America. The book also covers non-taxonomic topics including evolution and ecology of fish assemblages, mating behavior, foreign fishes, fishes as models for scientific studies, and conservation overviews. Johns Hopkins University Press is the publisher, with volume 1 published in 2014 and volume 2 scheduled for publication in the spring of 2020. Volume 2 will cover 19 families (Characidae to Poeciliidae), with contributions from 38 different authors. The volume includes families of major interest to those concerned about desert fishes, including Poeciliidae, Cyprinodontidae, Fundulidae, Goodeidae, and Profundulidae.

ABSTRACT. Gila Trout, Oncorhynchus gilae, is endemic to streams above 1524 m in the Gila River basin of Arizona and New Mexico. Gila Trout were originally listed as endangered under the Endangered Species Act in 1973 and were down listed to threatened in 2006. One of the actions required to recover and delist Gila Trout is their repatriation into streams throughout their historic range. Currently, the most common way to repatriate Gila Trout is to stock Gila Trout that are 6-8 months old. This method is largely successful, but it has its disadvantages. Many Gila Trout recovery streams are remote and are difficult to access. As a result, a large amount of effort is required to carry 250 to 500 Gila Trout in to stock in a stream. One alternative to fish stocking may be the stocking of fertilized eggs into artificial redds built in the stream. We tried this approach on two Arizona Gila Trout recovery streams, Grapevine and Frye Creeks. We stocked 19,000 Gila Trout eggs at Grapevine Creek and 24,000 Gila Trout eggs at Frye Creek. Visual surveys one month after stocking found good survival of Gila Trout at Grapevine Creek, but no survival at Frye Creek. Stocking eggs may provide a method for repatriating Gila Trout eggs that requires less manpower and reduces the cost of raising fish.

ABSTRACT. Passive integrated transponder (PIT) tag technology is commonly used as a tool to track native fish stocking survival, movement, and provide population estimates in the Colorado River. As any technology, PIT tagging has changed and advanced over time. The long life span of native fish in the Colorado River Basin present an interesting problem for managers using PIT tags, as fish have survived several iterations of this technology. This study focuses on our ability to use current and past technology to detect two types of PIT tags. We tested the read range and capabilities of the three most commonly used readers (Destron/IDI, Cheeseblock (BioMark 2001F), and HPRLite) on 400 kHz and 134.2 kHz tags, and when of both types of tags were present. We found that many factors affect read range including interactions between tags, orientation of tags, model of reader, and batch number of PIT tags. The Destron/IDI had the longest read range and was able to read all 400 kHz tags, even in the presence of a 134.2 kHz tag. The other two readers had a more limited read range and were unable to pick up 400 kHz tags if a 134.2 kHz tag was present.

ABSTRACT. Recent collections of Yaqui Catfish, Ictalurus pricei, in northwest Mexico record their existence only for the Arroyo Cajón Bonito in Sonora, and the Tutuaca River in Chihuahua. Following the recent conservation interest of the species by NGOs and government agencies on both sides of the border, due to the imminent risk of extinction in which it is found, it began with the capture of Yaqui Catfish from the Cajón Bonito Stream in order to initiate a reproductive stock, between other initiatives of knowledge of the species. Twenty individuals of Yaqui Catfish were captured during 2018 and 2019, of which 16 were initially kept alive in a pond of the Area Voluntarily Dedicated to the Conservation of Cuenca Los Ojos in Rancho San Bernardino, Sonora. In the first attempt to transport these live specimens to facilities of the Centro Acuícola del Estado de Sonora (CAES) near Obregón City (Instituto de Acuacultura del Estado de Sonora, IAES), five specimens were transferred, and are currently under the technical care of the staff of the CAES. These specimens receive commercial food for catfish normally and show no signs of stress so far. The genetic identity of the 18 specimens of the reproductive stock has been analyzed using mitochondrial and nuclear genes. Two hybrids have been detected between Yaqui and Channel Catfish, Ictalurus punctatus, and are excluded from captive stock. In addition, the Oklahoma State University (OSU) has begun the study of environmental DNA (eDNA) in selected localities throughout the Yaqui River basin in order to detect potential sites of occurrence of the species not yet reported. The project has a collection license granted by the Dirección de Vida Silvestre (DVS) of the Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT) and has exercised shared funding from the University of Sonora, Desert Fishes Council, IAES, Cuenca los Ojos and OSU. The project raises the need for financing to develop all the activities, which include the use of specific microsatellites for the analysis of hybridization between these catfish, the reproduction and cultivation of Yaqui Catfish, the training for pilot cultivation of species with management and conservation purposes in Sonora.

ABSTRACT. The Sonoyta Pupfish, Cyprinodon eremus, is an endemic species of the Sonoyta River basin (Sonora) and the Quitobaquito spring (Arizona). Its current distribution is restricted by anthropogenic impacts and does not have an official conservation status. As an immediate conservation strategy in response to the imminent removal of its population in Mexico, four artificial refuges was built in Sonora, however, its establishment was without considering genetic indicators of the population of origin. The hypothesis states indicators of genetic variability changes and inbreeding in artificial refuges were caused by isolation and genetic differentiation due to bottlenecks and founder effect. The objective is to evaluate their genetic variability and inbreeding level in three artificial refuges and the wild population in Sonora, by means of ten microsatelite loci and determine parameters of genetic variability, genetic equilibrium, fixation index (Rst and Fis) and presence of bottlenecks. The results indicate that there is a high genetic variability in all populations; the population of the Centro de Estudios de Desiertos y Océanos (CEDO) has the greatest genetic diversity. All refuge and wild populations have a genetic disequilibrium caused by heterozygous deficits. Fixation indices show little genetic differentiation (Rst = 0.007) and a high inbreeding coefficient (Fis = 0.26) indicating that there is divergence among all populations due to isolation. Presence of bottleneck was detected in the artificial refuge of the Centro Ecologico de Sonora (CES). In conclusion, only the population of the CEDO is potentially useful to increase the genetic variability of the rest of the refuges, since the indicators of genetic variability agree with those of the wild population, this population could be subject of source individuals for their reintroduction in the Sonoyta River in case it is required.

ABSTRACT. Flight capability in insects is important for microhabitat colonization, this dispersion is of great reproductive importance since this maintains the genetic flow between populations, and nevertheless, the high energetic cost of flight is an impediment for insects that cross great distances looking for these habitats. In drylands non-perennial water bodies are important temporal niches and their colonization is vital for the aquatic community that lives in them, that is why the study of gene flow between these populations is critical to know the various effects that can occur in them. The El Pinacate y Gran Desierto de Altar Biosphere Reserve has many non-perennial water bodies with variable hidroperiods and are separated between arid lands, inhabitants of this water bodies include soldier flies (Stratiomys sp.) which colonization mechanisms and actual status of the population are unknown. The gene flow between populations permit to have a high degree of heterozygosity and therefore to have a great genetic variability to survive to changing conditions, in regions like El Pinacate where water scarcity is high is of great importance to know the estate of populations of aquatic insects like soldier flies that depend on the essential resource. The objective of this work is to determine the gene flow of Stratiomys sp between various water bodies in the volcanic plate of the El Pinacate Biosphere Reserve. We will use at least 10 microsatellites loci from DNA extracted from larvae collected during the rainy season, to evaluate potential dispersion between populations. This studies allow us to make inferences of the population status and extrapolate the information for the study of the aquatic communities.

ABSTRACT. The Longfin Dace, Agosia chrysogaster, is one of the endemic species that inhabits the Gila River basin (Santa Cruz and San Pedro rivers), the Colorado River in the southwestern United States of America (USA) and the Sonoyta and de la Concepcion rivers in the northwest of Sonora. Currently, the population of the Sonoyta River is virtually extirpated from its natural environment, and the remaining population of few individuals is in a refuge in the Centro de Estudios de Desiertos y Océanos (CEDO) in Puerto Peñasco, Sonora. Its current conservation status of threatened with extinction according to NOM-059-2010 also includes the historical distribution of the Mexican Longfin Dace (Agosia n sp), which makes it inoperative. Thus, it is necessary to confirm the specific identity of the population of the Longfin Dace remaining in the Sonoyta River by means of genetic criteria to recognize their specific identity, their genetic variability and phylogenetic affinity with the rest of the populations in their natural distribution. Therefore, through molecular analyzes based on the variation of mitochondrial and nuclear genes, specific identity studies (COXI) will be carried out using the DNA Barcoding technique, genetic variability (ND2) and inbreeding degree of the population in refuge, as well as phylogenetic affinity within the species (Cyt-b). The information generated in this project will serve as a basis for the recovery and management of a species in the Sonoyta River basin.

ABSTRACT. In recent years, investigations of widespread North American freshwater fishes have revealed significant levels of cryptic diversity, especially in minnows and shiners of the family Cyprinidae. The Sand Shiner, Notropis stramineus (Cope, 1865) is a small North American minnow with an expansive distribution east of the Continental Divide present abundantly in a portion of the southwestern U.S. to northern Mexico. Though N. stramineus is currently regarded as a single species, previous taxonomic authorities recognized two subspecies (N. s. stramineus and N. s. missuriensis) still recognized as valid by some authors. This two subspecies classification is based largely on minor differences in scale-row counts between individuals inhabiting tributaries to the Great Lakes, upper Mississippi and Texas gulf coast river systems (N. s. stramineus) and those inhabiting the Missouri and Arkansas River systems (N. s. missuriensis). Analysis of an unpublished, multi-locus genetic data set has revealed the presence of multiple genetically distinct lineages geographically incompatible with the aforementioned subspecies designations. These results instead suggest that N. stramineus may represent a super-species-complex, comprising multiple (4+) similar looking, yet genetically distinct species, the majority of which have yet to be formally recognized and diagnosed with phenotypic characters. To uncover morphological traits useful for distinguishing between putative members of this super-species-complex, we have analyzed geometric morphometric landmark-derived characters to investigate whether consistent phenotypic variation exists across the range of N. stramineus sensu lato and whether patterns of phenotypic variation are congruent with geography and genetic lineage membership.

ABSTRACT. The Oregon/Northern California Area Report includes activities to report to the council from the northwestern extreme of the desert region which includes several endorheic or terminal lake basins in Oregon, northeastern California, and northwestern Nevada (Fort Rock, Chewaucan, Goose, Warner, Catlow, Alvord, Malheur, Coyote lakes, and Quinn River basins). This region supports remnant fish faunas that once inhabited extensive pluvial Pleistocene lakes. In 2019, OSU and other investigators are re-evaluating the taxonomy of the Torrent Sculpin, Cottus rhotheus, across the Pacific Northwest, including parts of Oregon’s desert. There are three genetically, geographically and morphologically distinct entities within the current concept of this species, meaning the species may be split taxonomically. The lab is testing whether Cottus gulosus and Cottus perplexus are distinct species in Oregon. That means that the range of the “true” Torrent Sculpin in Oregon is less extensive than currently conceived. Lake County Umbrella Watershed Council (LCUWC) along with several partner organizations and agencies have formed the Warner Basin Aquatic Habitat Partnership to develop fish passage solutions for Warner Suckers, Catostonus wasrnerensis, Redband Trout, Oncorhynchus mykiss, and other aquatic life. The LCUWC designed, planned, and implemented projects benefiting Warner Sucker and Redband Trout. Oregon Department of Fish and Wildlife (ODFW) Lakeview District provided updated information on Redband Trout surveys conducted in the Warner and Abert lakes basins. ODFW also conducted a population estimate of Foskett Speckled Dace, Rhinichthys osculus, in 2019 and observed an estimated population change from 4,279 (95% CI 3,878 to 4,782) in 2017 to 9,493 (95% CI 9,265 to 9,740) in 2019. The Fremont-Winema National Forest, Eastside Fish Program reported completion of several aquatic habitat restoration projects on the upper Sycan, and North Fork Sprague Rivers as well as several smaller tributary streams. The Fish and Wildlife Service (FWS) proposed to remove the Borax Lake Chub, Siphateles boraxobius, from the ESA list February 26, 2019. Comments were received from peer reviewers and the public. The final decision will publish in the Federal Register approximately one year from the proposal. The FWS also finalized a rule to remove the Foskett Speckled Dace from the list on September 13, 2019.

ABSTRACT. The Mexican Roundtail Chub, Gila minacae, possess a widespread distribution in the Yaqui River basin and other adjacent southward drainages at the Sierra Madre Occidental in northwest México. However, the formal description of G. minacae was based exclusively on specimens taken from the type locality on the Papigochic River at Miñaca, in the Yaqui River basin. Therefore, all the populations currently considered part of the G. minacae lineage and inhabiting the drainages beyond the south of the Yaqui River basin have not been formally characterized in terms of their meristic and morphometric variation. We performed a morphological characterization of populations of the Gila minacae lineage inhabiting the Yaqui River basin, and the southern populations from the Fuerte, Sinaloa, and Culiacán River basins, plus other congeneric species from the Sierra Madre Occidental, Mexico. Discriminant function analysis based on 33 morphometric and six meristic characters applied to 209 Gila spp. specimens revealed 15 body characters to be significantly different (p < 0.01) among the taxa compared. Canonical variables 1 and 2 explained 76.8% of the total variation among the populations analyzed. Morphologically, the southern Gila sp. populations inhabiting the Fuerte, Sinaloa and Culiacán River basins are divergent from both the Gila minacae found in the Yaqui River basin and the other species analyzed. The southern populations of Gila sp. have a deeper body and lower numbers of gill rakers, dorsal fin rays, and lateral line scales than G. minacae from the Yaqui River basin. The morphological differences detected here among populations of G. minacae from the Yaqui River basin and the southern populations suggest the presence of at least two significant evolutionary units within the Gila minacae lineage.

ABSTRACT. I will examine how Comanche Springs Pupfish, Cyprinodon elegans, at Balmorhea State Park live. I will watch pupfish videos to see what they do. My hypothesis is that they will be moving, playing, an eating. I will record my observations and make some graphs.

ABSTRACT. San Juan River larval fish surveys have occurred annually since 1998 to monitor reproduction by federally endangered Colorado Pikeminnow, Ptychocheilus lucius, and Razorback Sucker, Xyrauchen texanus. As part of this monitoring effort, spawning periodicity of both species was back-calculated annually using growth equations developed in the Upper Colorado River basin. While back-calculated spawning dates generated from these models were assumed to be approximations, use of the equations was limited, particularly for Razorback Sucker, because older age-0 fishes produced unfeasible spawning dates. In 2017, San Juan River basin-specific growth curves were developed for Colorado Pikeminnow and Razorback Sucker, using larvae collected in the San Juan River from 2009 to 2017. These growth curves were used to estimate age in days from standard length of age-0 fish. Back-calculated age was used to calculate spawning periodicity and was compared against spawning periodicity calculated with the upper Colorado River basin equation and daily otolith ages for both species. Initial results indicated that spawning periodicity produced by San Juan River basin growth curves was significantly different from those produced by the Upper Colorado River basin growth curves but not from spawning dates calculated from otolith ages. We then used species-specific San Juan drainage growth curve equations to back-calculate spawning dates of all larval Colorado Pikeminnows and Razorback Suckers collected in the San Juan River between 2000 and 2018. Spawning periodicity from the San Juan River equations was compared against that of the Colorado basin equations using ANOVA. The San Juan River is largely a dam-regulated system with water release from Navajo Dam managed to mimic a natural flow regime. Inaccurate back-calculation of spawning dates could result in missed opportunities for water release from dams or inadvertently harm larval fishes.