To appraise conservation status of the Yaqui catfish Ictalurus pricei, we reviewed literature and unpublished records on a captive stock, examined voucher specimens at museums, re-sampled historical localities in the Yaqui, Mayo, and Fuerte river basins, and we surveyed rivers further south. A total of 72 specimens of native Ictalurus was collected in the Yaqui, Fuerte, Sinaloa, Culiacán, and San Lorenzo river basins. No native Ictalurus was collected in the Mayo Basin. Distribution of the Yaqui catfish appears restricted to the Yaqui, Mayo and Fuerte river basins, all of which now harbor nonnative blue (I. furcatus) and channel (I. punctatus) catfishes. The nonnative black bullhead (Ameiurus melas) is now known from the Yaqui Basin and the flathead catfish (Pylodictis olivaris) has been recorded anecdotally in the Yaqui Basin. Threats to the Yaqui catfish have increased in recent years and hybridization with the channel catfish now appears widespread. We conclude that the Yaqui catfish should be considered endangered throughout its range and that status of native populations of Ictalurus in the United States and Mexico should be reviewed and management intensified. Para evaluar el estatus de conservación del bagre de Yaqui Ictalurus pricei, revisamos la literatura y registros no publicados de una línea cautiva, examinamos ejemplares de referencia de museos, muestreamos nuevamente las localidades históricas en las cuencas de los ríos Yaqui, Mayo, y Fuerte y muestreamos los ríos más al sur. Recolectamos un total de 72 ejemplares de Ictalurus nativos en las cuencas de los ríos Yaqui, Fuerte, Sinaloa, Culiacán, y San Lorenzo. No recolectamos ejemplares de Ictalurus nativos en la cuenca del Mayo. La distribución del bagre de Yaqui parece estar restringida a las cuencas de los ríos Yaqui, Mayo, y Fuerte, las cuales albergan actualmente los bagres no-nativos I. furcatus y I. punctatus. El bagre no-nativo Ameiurus melas se conoce para la cuenca del Yaqui y el bagre Pylodictis olivaris se registra anecdóticamente para la cuenca del Yaqui. Las amenazas para el bagre Yaqui se han incrementado en años recientes y la hibridación con I. punctatus se ha extendido. Concluimos que el bagre de Yaqui deberá considerarse como en peligro de extinción a lo largo de su distribución y que el estatus de las poblaciones remanentes de Ictalurus en los Estados Unidos y México deberá revisarse e intensificar su manejo.

1. Exotic species threaten native species worldwide, but their impacts are difficult to predict. 2. Stable isotope analysis was combined with field competition experiments to predict how an invasive African cichlid fish, Hemichromis guttatus, might affect native fish in the desert springs of Cuatro Ciénegas, Mexico. 3. Stable isotope analysis suggested diet overlap between the invader and juvenile endemic cichlids, and field experiments verified that the invader reduces growth rates of the juvenile endemics through competition, but has smaller effects on adults. 4. Competition between juvenile endemic cichlids and the invader was asymmetric, with the exotic out-competing the native, suggesting the potential for competitive exclusion if the invasion is not stopped. 5. These results suggest that exotic removal programmes in Cuatro Ciénegas should focus on removing/reducing populations of the exotic cichlid in habitats where juvenile native cichlids are concentrated. 6. This approach could help focus efforts to manage exotic species before populations of native species have crashed, when it is too late to intervene. Copyright © 2011 John Wiley & Sons, Ltd.

Full text here: "This important book is basically about fishes of Arizona and very small areas of adjacent U.S. states, as well as all of the Mexican states of Baja California (North and South) and Sonora, and a very small piece of westernmost Chihuahua. After a short introduction (five pages), the first 17 pages of Chapter 2 provide background on topography, as well as geologic, climatologic, and vegetation history relevant to ecology and evolution of the natural aquatic ecosystems of a much broader region—all major North American deserts. The next 24 pages are an overview of the extensive recent human alterations of aquatic systems in the hydrologically defined focal area. Conservation issues are mentioned in Chapter 2, but Chapter 3 focuses on that and although short (4.5 pages), it is anything but sweet, strongly criticizing the political system and management agencies for failure to apply sound science and allowing the long, continual decline of native fishes to go unchecked. Chapter 4 (203 pages) contains brief guides to anatomy and identification, family and species keys, and very well-done, comprehensive species accounts for 173 species (75 native, including four undescribed). Content covering northwest Mexico is noticeably lighter than for Arizona. All species ever recorded are included, whether or not they have self-sustaining populations. A very strong point is the book's comprehensive (72 pages) Literature Cited section, including substantial “gray” literature that previously had been underutilized and hard to find. I would have liked to have seen more citation of “raw” data (e.g., museum catalog numbers for key records) and was a bit surprised to see illustrations ranging from many very simple line drawings (little more than outlines) through occasional black-and-white photographs, but there are also many higher quality line drawings with greater detail and 47 nice color plate illustrations. Dot and shaded maps are provided for native species only. I found very few errors, all minor, and overall found this to be an authoritative and valuable contribution on this important and very much imperiled fauna and the complex issues that imperil it."

The mission of the Desert Fishes Council is to preserve the biological integrity of North America's desert aquatic ecosystems and their associated life forms, to hold symposia to report related research and management endeavors, and to effect rapid dissemination of information concerning activities of the Council and its members.

The mission of the Desert Fishes Council is to preserve the biological integrity of North America's desert aquatic ecosystems and their associated life forms, to hold symposia to report related research and management endeavors, and to effect rapid dissemination of information concerning activities of the Council and its members.

The mission of the Desert Fishes Council is to preserve the biological integrity of North America's desert aquatic ecosystems and their associated life forms, to hold symposia to report related research and management endeavors, and to effect rapid dissemination of information concerning activities of the Council and its members.

The mission of the Desert Fishes Council is to preserve the biological integrity of North America's desert aquatic ecosystems and their associated life forms, to hold symposia to report related research and management endeavors, and to effect rapid dissemination of information concerning activities of the Council and its members.

The trout species of Mexico‘s Sierra Madre Occidental (SMO) range have been essentially ignored in science except for the efforts of Needham and Gard (1959) in the mid-20th century. Even after their work documenting the existence of the Mexican Golden Trout Oncorhynchus chrysogaster no focused efforts to study the diversity in the SMO south of the USA were initiated until 1997. Sampling in the Sierra Madre Occidental is extremely difficult, but our efforts since that year have revealed that all of Mexico‘s SMO trout are native (except for hatchery-reared) to the Río Yaqui system southward to the Río Acaponeta, and in the Río Conchos drainage. Morphological and genetic studies of the populations from these rivers support the hypothesis of multiple divergent lineages that we argue are distinct evolutionary species. Conservation and protection of these lineages are critical and should constitute a coordinated effort involving governmental agencies, private organizations, nonprofit groups, and individuals. More inventory work is warranted to better understand the distributions of the native trout and efforts should be made to eliminate the introduction of ―hatchery rainbow trout‖ Oncorhynchus mykiss into grow-out facilities in these mountains, instead replaced with propagation efforts on the different native species within their respective drainages. The diversity of wildlife and natural features across the SMO could, with proper planning and maintenance, serve as a fundamental, environmentally sound, sustainable resource for the region via ecotourism.

Collections of 231 catfish from 34 localities were surveyed for mtDNA (399 base pairs of cytochrome b) and morphological evidence of headwater catfish Ictalurus lupus in areas of historical occurrence in Texas and New Mexico. The species is of concern for conservation managers, primarily because of the potential for population losses from competition and hybridization with channel catfish I. punctatus. For cytochrome b, there were two deeply divergent (4.8–6.1%) groups, a channel catfish clade of 14 haplotypes (0.8% to 1.3% divergence) and a headwater catfish clade of two haplotypes (1.0% divergence), associated with morphotypes of channel catfish and headwater catfish, respectively. Morphotypes were based on field identification and a canonical discriminant function utilizing external morphology. All specimens from the Nueces River and the main-stem Rio Grande and the Pecos River conformed to morphological and mtDNA expectations for channel catfish. Apparently pure populations of headwater catfish were found only in two relatively isolated situations (Rocky Arroyo, New Mexico, and San Solomon Spring, Texas). Additional genetic evidence of headwater catfish was restricted to four populations in streams that are direct tributaries of either the Pecos River or the Rio Grande. Two of these populations (Independence Creek and Dolan Creek—Devils River) were morphologically distinct from, but shifted toward, the morphotype of channel catfish. A third population (Pinto Creek) was morphologically indistinguishable from channel catfish, and individuals from the fourth population (Delaware River) had morphotypes consistent with both species. The Pinto Creek, Independence Creek, and Delaware River populations exhibited mtDNA haplotypes from both species, whereas the Dolan Creek—Devils River population was fixed for a haplotype from the headwater catfish clade. A survey of early collection records tentatively suggests that hybridization between headwater catfish and channel catfish might be a result of relatively recent introduction of the latter to the Rio Grande basin.

In 2010, the Great Plains LCC funded a project that compiled and standardized more than 76,000 existing data records from natural history museums. Led by Dean Hendrickson, Curator of Ichthyology at the University of Texas Austin, the researchers compiled extensive, high quality data sets on occurrences of fishes, aquatic reptiles and amphibians, freshwater mussels, and cave invertebrates from the Texas, New Mexico, Colorado and Oklahoma portions of the GPLCC region. Much of the wealth of information stored in natural history collections requires substantial investment in order to make it accessible and useful to natural resource managers and researchers. Over 55 percent of the records provided by this project are georeferenced and in a format suitable for immediate use in climate models and conservation planning. “This project provides essential data to our partners throughout the region,” says GPLCC Science Coordinator James Broska. “Sharing data and making it easily accessible is a primary function of LCCs.” As part of the project, researchers demonstrated how this type of occurrence data can be effectively combined in computer models with various environmental data in ways that greatly facilitate planning at the landscape level. Using fish occurrence data for Texas, they applied it in rigorous modeling, climate change and conservation network planning exercises. The models incorporated recent occurrence records and climate data and were validated to be powerful predictors of actual occurrences under current conditions. The team then replaced the current climate data with predicted future climate data and computed how species’ distributions would shift if those climate predictions were realized. While the demonstration was done statewide for Texas, it used species that occur in, and are of particular interest to, the Great Plains LCC. In the final report, the researchers describe the use of the ConsNet conservation planning program to produce a portfolio of priority area sets for conservation network planning. Initial results from ConsNet used the models described above to integrate a great diversity of biological knowledge, summarizing it into a baseline starting set of priority areas for management actions based strictly on maximization of representation of biodiversity. Managers and policy makers can then continue analysis and prioritization in Consnet, adding additional factors to the biology-based starting scenario, such as habitat impaction and socioeconomic or ecosystem service cost-benefit parameters. ConsNet can easily and interactively produce large numbers of variations based on diverse criteria, thus providing a large variety of alternatives to consider for potential implementation. “This project has begun to compile the basic historic, current and future species occurrence and environmental data sets the Great Plains LCC will need to perform such analyses for its own geographic scope, perhaps applying the same methodologies, data sets and tools we developed and provided in this project,” says Hendrickson. “We look forward to continuing our work with the Great Plains LCC to build and improve its data resources and tool set to help address the complex issues it will face as it strives to attain its long-term conservation and sustainability objectives.”

Sprawling across a cactus-studded valley in México's Chihuahuan Desert is a place like no other on the planet. . It's called Cuatrociénegas, and it is a crunchy expanse of land isolated in a basin ringed by mountains like salt on the rim of a margarita glass. The seemingly dry, desert area, however, is best known for its life-giving waters—pools, wetlands and rivers filled to the brim with an amazing assortment of unique species. "This is an incredibly diverse area for this part of the world, with more endemic species per area than the Galápagos Islands," says Dean Hendrickson, curator of ichthyology at the Texas Natural Science Center. But Cuatrociénegas is not immune to change, and its rare ecosystems are under increasing pressure from climate change, invasive species and agriculture. Hendrickson, who has been visiting the area since 1979, now finds himself working with others to forge a sustainable future for the region. "My vision is to get a big interdisciplinary, international project going and try to find solutions that we can propose to the local community," he says. He has established a permanent research station in town, and he hopes this will encourage more researchers from other fields to begin projects there. "There are very complex issues here that go way beyond simple biology and conservation and get into sociology and economics," he says.

Researchers at the University of Texas at Austin are studying the biology and hydrology of Cuatrocienegas, a rare and endangered desert oasis in northern Mexico. Covers research of Dean Hendrickson and Brad Wolaver.

México is the southernmost country in North America, and extends into Central America, south of the Isthmus of Tehuantepec. The northern half of México is located on the Temperate belt and is arid in character (Nearctic), while the rest is within the Tropical belt (Neotropical). Climate varies from extremely temperate desert in the north, to tropical humid in the south. México has more than 500 freshwater fish species, about 271 of them country endemics, and approximately 48 endemics from binational basins. There are still some 30–40 fish species not yet described. There are 563 fish species colonizing coastal flood plain species. In addition to the numbers of colonizing fishes, the burden of introduced exotics has also been growing. In 1904, only 4 species were recognized as exotics; by 1997 the number had increased to 94, and by 2008 to 115. The main fish collections in Mexico are at IPN, UNAM, and UANL and are the most representative, being national in scope, although concentrated in the tropics, central region, and general in coverage, respectively. The decline of the native fish fauna has been in focus in recent years, usually as trend-in-time comparisons, where the loss of native forms and increase of exotics and/or colonizer species is evident in many basins, mainly in Río Balsas, Río Grande, and Río Lerma-Santiago. As a result, the numbers of species reported at some degree of risk have been increasing also, from 17 in 1963 to 192 in 2005. The trends in colonizers, exotics, and species at risk among Mexican fishes are parallel. The Index of Biological Integrity (IBI), in either its geographical, or historical form (IBIh), has been applied to the Rio Grande/Río Bravo basin, USA and México. IBIh values go between 0–91 (average 31). Alien species are regarded as detrimental. Overall, the IBI trends have been similar in all regions, starting from 70–95% in upper reaches, decreasing to less than 0–35% in the lower reaches of West central basins, and then down to 15% or less near the Lower Rio Grande delta. Several alien species of plecos have been recognized in the rivers Balsas, Grijalva-Río Usumacinta complex, and, also, one in the Rio Grande. Mexican rivers are notoriously dewatered in the northern half of the country. Until 1962, the Rio Grande had an average runoff of 12,000+ millions of cubic meters/year; however by 2002 it was less than 2% of that value. The river went nearly dry along the Big Bend region and was dry for months in the delta region, both in 2002 and 2004. The Rio Grande is mostly dry north of the Río Conchos junction, its main Mexican tributary, and other tributaries provide now between 1% (Río San Juan) and 20% (Río Conchos) of pre-1960 runoff. A modified Index of Biological Integrity for Rio Grande resulted in grades from 70 to 95% of the baseline in upper reaches, less than 35% in lower reaches, to less than 15% near the coast. The Texan version of the IBI was not representative as it suppresses data on euryhaline fishes. The reports of total toxics were masked, since the sum should have included both organics and heavy metals exceeding USA regulations to the total count, but only one of the two was included.

This is the third compilation of imperiled (i.e., endangered, threatened, vulnerable) plus extinct freshwater and diadromous fishes of North America prepared by the American Fisheries Society's Endangered Species Committee. Since the last revision in 1989, imperilment of inland fishes has increased substantially. This list includes 700 extant taxa representing 133 genera and 36 families, a 92% increase over the 364 listed in 1989. The increase reflects the addition of distinct populations, previously non-imperiled fishes, and recently described or discovered taxa. Approximately 39% of described fish species of the continent are imperiled. There are 230 vulnerable, 190 threatened, and 280 endangered extant taxa, and 61 taxa presumed extinct or extirpated from nature. Of those that were imperiled in 1989, most (89%) are the same or worse in conservation status; only 6% have improved in status, and 5% were delisted for various reasons. Habitat degradation and nonindigenous species are the main threats to at-risk fishes, many of which are restricted to small ranges. Documenting the diversity and status of rare fishes is a critical step in identifying and implementing appropriate actions necessary for their protection and management.

The variation and composition of Mexican wild trout mitochondrial DNA haplotypes throughout northwestern Mexico was determined by means of polymerase chain reaction-restriction fragment polymorphism analysis (PCR-RFLP), of one region of mitochondrial DNA between cytochrome b and the D-loop. This analysis was based on 261 specimens taken in 12 basins and four hatcheries from northwestern Mexico. From 23 haplotypes, 15 wild trout haplotypes were identified and classified in four groups: (1) one restricted to Nelson's trout (Oncorhynchus mykiss nelsoni), (2) four restricted to R¡o Mayo and R¡oYaqui trout (O. mykiss sspp.), (3) six to Mexican golden trout (O. chrysogaster) with two subgroups, and (4) one exclusive to R¡o Piaxtla trout. Distributions of native haplotypes broadly overlap the distribution of non-native hatchery rainbow trout reflecting the historical management of introductions of exotic rainbow trout and the artificial transference of these trout among basins.

We examined foraging behavior (microhabitat use and feeding behavior) in a trophically polymorphic cichlid fish, Herichthys minckleyi, to address several questions regarding resource partitioning in this threatened species. These include: (1) do morphotypes demonstrate different foraging behaviors? (2) do individuals within a morphotype vary in their foraging behavior (e.g. are some individuals specialists, only using a subset of available resources, while other are generalists)? (3) do foraging behaviors vary between isolated pools? (4) do foraging behaviors vary across seasons? We quantified microhabitat use and feeding behavior for over 100 individuals (of two morphotypes) feeding freely in two isolated pools (populations) and across two seasons (winter and summer). We found differences in foraging behavior between morphotypes and individual specializations within morphotypes; i.e. some individuals specialize on certain food resources by using a few feeding behaviors within a subset of microhabitats, whereas others employ a range feeding behaviors across many microhabitats. Foraging behavior also varied between pools and across seasons. This spatial and temporal variation in foraging behavior and resource use may serve to maintain this polymorphism, as the relative fitness of the each morph may vary over space and time

The evolutionary viability of an endangered species depends upon gene flow among subpopulations and the degree of habitat patch connectivity. Contrasting population connectivity over ecological and evolutionary timescales may provide novel insight into what maintains genetic diversity within threatened species. We employed this integrative approach to evaluating dispersal in the critically endangered Coahuilan box turtle (Terrapene coahuila) that inhabits isolated wetlands in the desert-spring ecosystem of Cuatro Ciénegas, Mexico. Recent wetland habitat loss has altered the spatial distribution and connectivity of habitat patches; and we therefore predicted that T. coahuila would exhibit limited movement relative to estimates of historic gene flow. To evaluate contemporary dispersal patterns, we employed mark-recapture techniques at both local (wetland complex) and regional (inter-complex) spatial scales. Gene flow estimates were obtained by surveying genetic variation at nine microsatellite loci in seven subpopulations located across the species' geographic range. The mark-recapture results at the local spatial scale reveal frequent movement among wetlands that was unaffected by inter-wetland distance. At the regional spatial scale, dispersal events were relatively less frequent between wetland complexes. The complementary analysis of population genetic substructure indicates strong historic gene flow (global FST = 0.01). However, a relationship of genetic isolation by distance across the geographic range suggests that dispersal limitation exists at the regional scale. Our approach of contrasting direct and indirect estimates of dispersal at multiple spatial scales in T. coahuila conveys a sustainable evolutionary trajectory of the species pending preservation of threatened wetland habitats and a range-wide network of corridors.