ABSTRACT. Our aim was to review the conservation status of Headwater Catfish, Ictalurus lupus, in the United States with emphasis on Texas populations. Our status assessment included evaluating change in geographic distribution over time and measuring introgression and hybridization with Channel Catfish, Ictalurus punctatus, to inform conservation prioritization. We used machine learning methods (random forest and boosted regression tree) to construct species distribution models based on historical and contemporary presence-absence data using 13 environmental predictors based on remotely sensed stream network data. We measured introgression and hybridization with the widely introduced Channel Catfish using external morphology and molecular markers. The sub-basin (8-digit hydrologic unit code) from which collections were made was the most important predictor variable across all models. Species distribution models illustrated temporal shifts in Headwater Catfish occurrence. Historically, Headwater Catfish occurrence was higher among streams with steeper slopes, greater distances from spring outflows, broader ranges of annual precipitation, and with greater portions of the network catchment classified as water. These shifts are likely related to both range contraction of the species and temporal variation in sampling locations. Morphological and molecular data revealed four genetically pure and isolated locations where conservation of Headwater Catfish phenotypes and genotypes are likely to be most successful. Species distribution models provide critical assessments of where a species might persist, but they require careful validation and cannot account for genetic introgression. Combining targeted sampling efforts with locations highlighted by SDMs and genetic analyses can be used to promote systematic conservation planning for rare and threatened species.

ABSTRACT. The 2019 Bonneville Basin Update will focus on the following three projects:

1) Snake Valley Hydrologic Monitoring: Wetlands in Snake Valley serve as critical habitat for at least five of Utah's Species of Greatest Conservation Need, including four species threatened by groundwater withdrawal. Utah Geologic Survey has developed a network of shallow wells to document baseline hydrologic conditions in these wetlands. Utah Geologic Survey and Utah Division of Wildlife Resources are uploading and processing the 10th year of pressure transducer data and producing a final report with a summary of existing data and recommendations for the future of the monitoring network.

2) Soda ash control of Green Sunfish, Lepomis cyanellus, and restocking Least Chub, Iotichthys phlegethontis At the Desert Fishes Council meeting in 2018 the United States Geologic Survey reported on the use sodium carbonate to manipulate pH levels in aquatic habitats and kill unwanted Green Sunfish (L. cyanellus). It was reported that pH returned to normal levels within 4 days. In the late summer of 2019 Utah Division of Wildlife Resources trialed this method to remove invasive Green Sunfish from a pond in Box Elder County. Following a successful treatment, this pond will be stocked with native Least Chub. The potential and primary benefit of this method vs more traditional chemical eradication is that the pond can be restocked sooner after a sodium carbonate treatment.

3) Springsnails (Pyrgulopsis) Conservation Agreement and Strategy and the 3 Pyrgulopsis spp. Status Assessment

Mollusks (including gastropods and bivalves) are one of the most imperiled group of organisms in North America. Their taxonomy, historical and current locations, and life history traits are not well understood. Prioritizing the monitoring and conservation of the 154 species of native mollusks in Utah has become a priority in preserving and gaining knowledge of these rare and sensitive species to preclude future Endangered Species Act listings.

ABSTRACT. Despite consistent Colorado Pikeminnow, Ptychocheilus lucius, reproductive success, first year survival of larval fish remains poor in the middle Green River, Utah. In 2012, we examined potential factors impeding age-0 Colorado Pikeminnow survival in nursery backwater habitats. Presence and arrival of larval Colorado Pikeminnow was verified by drift net sampling conducted near the Split Mountain boat ramp (river mile [RM] 310) in Dinosaur National Monument and larval seining that took place in downstream backwaters. Twelve randomly selected backwaters (RM 305–273.5) were blocked off and depleted of nonnative fishes with a beach seine (≥ 90% depletion), then assigned one of three possible treatments: (1) four backwaters that were not blocked after initial depletions, (2) four backwaters blocked by 1/4" mesh block nets, and (3) four backwaters blocked by 1/2" mesh block nets. Experimental backwaters were revisited every other week on six separate occasions (10 July–25 September 2012) to monitor fish community response over time; changes in fish community composition were analyzed using a Repeated Measures ANOVA. Given that environmental conditions (i.e., dry hydrology) and deteriorating habitat quality were not conducive to Colorado Pikeminnow larval drift, arrival in nursery areas, or age-0 recruitment in 2012, other age-0 native fishes (mainly Flannelmouth Sucker, Catostomus latipinnis) provided helpful insights on the effects of our experimental design. Abundance of both native and nonnative fish (mainly small-bodied cyprinids) was greatest in 1/2" mesh blocking treatments. Moreover, native fish were completely absent from unblocked backwaters before the fourth sample period (20–22 August 2012) and nearly eliminated from 1/4" mesh blocking treatments before the fifth sample period (4–5 September 2012). Additionally, unblocked backwaters contained the lowest abundance of all species, suggesting that predation by nonnative piscivores (e.g., Smallmouth Bass, Micropterus dolomieu) coming from riverine habitats may be a significant threat to small-bodied fishes and blocking treatments can positively influence survival in nursery areas. By blocking backwater nursery areas, we created predator free habitats that benefited most species of small-bodied fishes. Despite higher abundance of small-bodied nonnatives in 1/4” and 1/2” mesh blocking treatments throughout our experiment, age-0 native fishes were also more abundant (1/2” mesh treatments containing the highest abundance). We do not discount that competition between age-0 native fishes and nonnative cyprinids can be intense in backwaters, but if we can control for predation by blocking backwaters, survival can be positively influenced despite ongoing competition for resources in nursery habitats.

ABSTRACT. Collaborative groups are often successful for developing and implementing conservation programs. However, sometimes... in official settings, efforts are influenced by the conflicting priorities, constraints and relationships of the participants' various institutions - to the detriment of the species we strive to protect. Informal working groups composed of individuals focused on common conservation interests can often explore and cultivate the synergy of individuals who bring together their shared interests, varied experience and the potential resources of their respective organizations. They may focus on species that are not currently priorities for management agencies. They can also facilitate the inclusion of diverse members of the community who may not typically have seats at the discussion. With gatherings outside the formal settings that many of us find ourselves in, the informal working group develops comradery and promotes intellectual exchange within a diverse conservation community. Examples are drawn from conservation efforts on Pacific Lamprey, Entosphenus tridentatus, pike minnows, Ptychocheilus spp., and Modoc Sucker, Catostomus microps.

ABSTRACT. Microplastics are an emerging contaminant of potential ecological concern in waterbodies across the world. One important point source of microplastic pollution is treated wastewater- after treatment this effluent is often discharged directly into streams. In southern Arizona, USA, effluent discharge supports perennial flow and riparian habitat in the Santa Cruz River but also brings microplastic pollution and its potential ecological challenges. In this project, we quantified microplastic concentrations in the water column, benthic sediment, and in Western Mosquitofish, Gambusia affinis, stomachs at 10 sites along the lower Santa Cruz River in Tucson, Arizona. We also compared microplastic concentrations before and during the monsoon season. We found four types of microplastics in the Santa Cruz River: fibers, fragments, film, and beads. Across all sites, microplastic concentration in the water column was ~33% higher during the monsoon, with the majority of pieces (≥80%) being fibers in both seasons. In benthic sediment, microplastic concentration was nearly twice as high before the monsoon season (340 ± 54 No./Kg) than during the monsoon season (153 ± 21), with fibers and fragments being the most common types of plastic found in sediment. Before the monsoon season, only three of the 200 mosquitofish sampled had ingested microplastics (100% fiber). In contrast, microplastics were found in 20 of 200 fish sampled during the monsoon season (85% fiber, 10% film, 5% fragment). This project provides the first evidence that microplastics are common in the water column and sediment of the Santa Cruz River, and that mosquitofish are more likely to ingest microplastics during the monsoon season. Future studies should assess the long-term impacts of these microplastics on the health and populations of aquatic species.

ABSTRACT. Colorado Pikeminnow, Ptychocheilus lucius, and Razorback Sucker, Xyrauchen texanus, federally endangered species, spawn annually in the San Juan River, yet a recruitment bottleneck persists between larval and juvenile life phases. The larval ontogenetic phase, though temporally short, is a period of high natural mortality and vulnerability to predation and starvation. Match/mismatch of spawning activities with larval abiotic requirements influence recruitment and survival. Age and growth of larval Colorado Pikeminnows (n = 514) and Razorback Suckers (n = 522) collected in the San Juan River from 2009 through 2017 were determined from otoliths. Daily ages of larval fish were used to calculate spawning dates and growth rates. Annual differences in adult spawning periodicity and larval fish growth rates were analyzed using ANOVA. Multiple linear regression was used to examine the relationship between abiotic variables (growing degree days (GDD), river mile, day length, and multiple parameterizations of discharge (Q) and temperature) on spawning dates and growth rates; multicollinearity was assessed for each model using variance inflation factors (VIF) and any variable with VIF>5 was removed. Colorado Pikeminnow growth rates and spawn dates were both significantly different across years (P < 0.0001). Length (SL) was predicted by age, mean July Q, river mile, water temperature on collection date, and GDD (R2= 0.72). Spawning periodicity was predicted by GDD, 7-day change in water temperature, 7-day change in discharge, and day length (R2 = 0.90). Adult Razorback Sucker spawn dates and larval fish growth rates were both significantly different across years (P < 0.0001). Length (SL) was predicted by age, mean April Q, river mile, and temperature (R2 = 0.76). Spawning periodicity was predicted by GDD, discharge, 7-day change in discharge, and day length (R2 = 0.99). Variation in Colorado Pikeminnow spawning periodicity was most impacted day length (53% of variation), whereas Razorback Sucker spawning periodicity was most impacted by GDD (76% of variation). Knowledge of spawning periodicity and growth rates, as well as the factors influencing them increases understanding of the needs of larval endangered Colorado Pikeminnow and Razorback Sucker and can help improve timing of management activities to benefit the species.

ABSTRACT. The Devils Hole Pupfish, Cyprinodon diabolis, has twice in recent years teetered at the edge of extinction with fewer than 40 animals observed during annual surveys. Establishing a captive population of these fish has proved an elusive goal for decades. Laboratory propagation in aquaria and refuge attempts in large outdoor tanks showed promise, but ultimately failed. Endeavoring to establish a lifeboat population, the Ash Meadows Fish Conservation Facility built upon earlier efforts by utilizing a two-fold approach to population establishment: laboratory rearing of wild-collected eggs through hatch and grow-out until adults were released into a 100,000-gallon refuge tank designed to mimic the challenging habitat and ecosystem of Devils Hole. Adults reared from wild-collected eggs failed to produce viable offspring in aquaria. However, adults stocked into the refuge tank began reproducing, producing successive generations within the refuge tank. Unlike wild-collected eggs, captive-produced eggs subsequently collected from the refuge tank population produced fish which spawned in aquaria and have produced entirely laboratory-reared offspring. Though successful, this approach met significant challenges in the technology required to simulate Devils Hole and to monitor the progression of a complex quasi-ecosystem, and necessitated novel approaches to pathogen and predator control and monitoring of fish and ecosystem health.

ABSTRACT. Bonytail, Gila elegans, and Razorback Sucker, Xyrauchen texanus, are two critically endangered fishes that have no known self-sustaining populations in the Colorado River. Both species have been stocked extensively throughout the basin and for Razorback Sucker this has resulted in thousands of adults persisting near several stocking centers. However, their presence is reliant on the release of tens of thousands of fish per year. For Bonytail, persistence beyond a year post-release has rarely been recorded despite large scale stocking similar in scope and numbers to Razorback Sucker. A major factor of both species failure to achieve recruitment levels that match mortality is a suite of predatory non-native fishes that have been introduced and established throughout the basin. These introduced species consume nearly all larval production by Bonytail and Razorback Sucker. They also increase post-stocking and adult mortality of both species by consuming stocked fish. Many of the introduced species are sport fish, and their wide-scale removal is not considered as a management option because states rely on revenue from anglers to support their programs. Bonytail and Razorback Sucker recovery in the Colorado River therefore depends on dramatic changes in wildlife management strategies or the discovery of novel approaches that allow large scale recruitment within the system in the presence of non-native sport fish. In the meantime, the only viable solution may be creation of aquatic environments that exclude piscivorous non-native fishes.

For the last 15 years proponents of the “backwater concept” in the lower Colorado River basin have worked to develop and test the idea that naturally recruiting populations of Bonytail and Razorback Sucker can be maintained in isolated, predator free off-channel habitat. Initial estimates of important demographic parameters have been calculated from monitoring data available through the online component of the lower Colorado River Native Fishes Database (ncreased.net). Monitoring in these backwaters includes continuous PIT scanning to track tagged individuals and annual netting efforts to capture and tag new recruits as well as recapture adults for health and growth studies. Annual adult survival of Razorback Sucker within monitored backwaters is consistently over 90%. Natural recruitment of Razorback Sucker in one backwater (Yuma Cove backwater) has resulted in a sustained population of more than 300 fish since 2013. Bonytail annual survival in backwaters typically has been less than 50%, but large recruitment events appear to maintain a relatively young population in at least one backwater (Imperial Ponds, Imperial National Wildlife Refuge). PIT scanning thus far has been less effective at tracking Bonytail populations due to the high turnover rate of these populations; most of the population is made up of untagged young fish. Results thus far are encouraging and support continued investigation toward eventual large-scale implementation of the backwater program.

ABSTRACT. The arid southwestern United States is home to many endemic freshwater fishes. The majority of these species are patchily distributed across this desert landscape and are experiencing range-wide declines due to habitat degradation, aridification through ground water depletion, and the introduction of non-native species. Though several of these desert fishes are already offered protection under the US Endangered Species Act and are relatively well-studied, many desert fishes are not yet protected at State or Federal levels and basic information that would aid conservation assessment (e.g., estimate of genetic diversity) is not currently available. This is the case for three species of freshwater fishes endemic to the lower Rio Grande drainage of south central Texas and northern Mexico: Cyprinella proserpina, Notropis megalops (Cyprinidae), and Etheostoma grahami (Percidae). We investigated levels of mitochondrial DNA diversity (multiple loci) within and between multiple TX populations (ranging from 4-6) of the three aforementioned species to provide baseline genetic data for future conservation assessment and management. Haplotype diversity (h) was generally low at sample locations for each of the three species (0-0.6786 for C. proserpina, 0.2-0.8333 for N. megalops and 0-0.6667 for E. grahami). A suite of standard conservation genetic statistics (including Pairwise Fst and AMOVA) support that idea that each of the three species comprises multiple populations that appear to be isolated from each other (though there is a lack of precise in some estimates due to small sample sizes). Low levels of genetic diversity and isolation are a bad combination but appear to be the norm for freshwater fishes of the Trans-Pecos. Additional work with nuclear markers and larger sample sizes will be needed to estimate effective population size and inbreeding coeficients for populations of each of the three species. These basic data will be important for the future conservation management of these relatively poorly studied lower Rio Grande endemic fishes.

ABSTRACT. The state of Nuevo Leon is in northern Mexico, and the Bustamante River is in the northwestern portion of this state. The area has limited rainfall and water is a vital resource for anthropocentric activities. The preservation of the rivers is very important, and the fish communities are override in this region. The study was conducted in a Priority Terrestrial Region, bordering Coahuila. This was the first study on fishes in this river, that the most of time is a close flood, is a tributary of the Salado River, for this reason, the objective was to determine the ichthyofauna, as well as conduct a zoogeographical and ecological analysis, and determine the presence of exotic and/or invasive species. Individuals were collected using seine net and electrofishing equipment, species were identified and stored in the Scientific Collection of FCB-UANL. We reported the presence of 8 native species, representing 6 families and 8 genera. There are 2 species under a status of protection laws of the country, Cyprinella cf. rutilla (Threatened) probably a new species and spotted minnow, Dionda melanops (Endangered). Zoogeographical affinity presents 4 Nearctic species and 4 Neotropical species, and two, Smallmouth Bass, Micropterus dolomieu and Tilapia probably Oreochromis sp. Indet., as exotic species were collected. It is important to continue surveys to detect species that are important for conservation.