Texas Natural History Collection - Fishes - Publications

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Ichthyological Survey of the Rio Salado, Mexico
(University of Texas at Austin, 1952-01-31) Guerra, Luciano Val
A survey of the fish fauna of the Rio Salado, which runs through the Mexican states of Tamaulipas, Nuevo Leon, and Coahuila, was selected as a suitable project for a Master's thesis after a thorough search of the scientific literature yielded very little information on the fish fauna of most of the Mexican rivers and none on the Rio Salado system. As an international dam is under construction across the Rio Grande at Falcon, Texas, I decided to make a study of the Rio Salado before introduction of exotic fishes disturbed the native fauna of this little-known stream system. I believe that a study of this nature would be of considerable value to fresh water fisheries work because all of the Mexican fish fauna native to Falcon Lake will come from the Rio Salado and its tributaries. After Falcon Dam is finished, the waters of the Rio Grande and its western tributaries, including the Rio Salado and its tributaries, will be impounded. With this impoundage of the waters, there will be some ecological changes in many of the stream systems concerned. These will be brought about mainly by the introduction of alien fish species into the lake and their subsequent migration into tributary waters, and by the effect of "backed-up" water in the lower Rio Salado and some of its tributaries. It has been the purpose of this work to study the ecological niches before they are changed so that fisheries planning concerning the waters of the lake may be based on sound scientific information and so that the present fauna may be compared with that which occurs after impoundage.
List of fishes known or expected to belong to the fauna of the Big Bend National Park
(Big Bend National History Association, 1958) Hubbs, Clark
The Heterothermic Vertebrates of the Lower Pecos River Drainage, Pecos, Crockett, Terrell and Val Verde Counties, Texas
(1979) Hillis, David
No abstract included in manuscript.
Reproductive Biology of Longfin Dace (Agosia chrysogaster) in a Sonoran Desert Stream, Arizona
(1982-05) Kepner, William G.
The longfin dace, Agosia chrysogaster Girard, is the most abundant native minnow of low elevation (< 1,500 m) streams in Arizona, parts of southwestern New Mexico, and northern Mexico. Reproductive life history of longfin dace was examined over a 12-month period (1977-78) in Aravaipa Creek, Graham and Pinal counties, Arizona. Adult males and females are sexually dimorphic, clearly distinguishable by differences in size of fins. Gravid females and tuberculate males persisted throughout the year and spawned in shallow saucer-shaped depressions in sand-bottomed backwaters and runs. Although individual spawning activity was asynchronous, populations reached peak spawning condition at least twice within the year. Peak reproductive activity was during increased discharge in spring and late summer. Fecundity was primarily a function of size. Ovary weight was highly correlated with fecundity and was the most reliable indicator of total mature ova produced.
Ciénegas - Vanishing Climax Communities of the American Southwest
(Desert Plants, 1985) Hendrickson, Dean A.; Minckley, W.L.
The term is here applied to mid-elevation (1,000-2,000 m) wetlands characterized by permanently saturated, highly organic, reducing soils. A depauperate flora dominated by low sedges highly adapted to such soils characterizes these habitats. Progression to ciénega is dependent on a complex association of factors most likely found in headwater areas. Once achieved, the community appears stable and persistent since paleoecological data indicate long periods of ciénega conditions, with infrequent cycles of incision. We hypothesize the ciénega to be an aquatic climax community. Ciénegas and other marshland habitats have decreased greatly in Arizona in the past century. Cultural impacts have been diverse and not well documented. While factors such as grazing and streambed modifications contributed to their destruction, the role of climate must also be considered. Ciénega conditions could be restored at historic sites by provision of constant water supply and amelioration of catastrophic flooding events.
An Annotated Checklist of the Freshwater Fishes of Texas, with Keys to Identification of Species
(The Texas Journal of Science, 1991) Hubbs, Clark; Edwards, Robert J.; Garrett, Gary P.
Forty-five families and 247 species of fishes are known to inhabit the freshwaters of Texas. We report on the distribution and status of these fishes and provide a key to their identification. Of the native fishes originally found in Texas, five taxa, Notropis orca (phantom shiner), Notropis simus simus (Rio Grande bluntnose shiner), Cyprinella lutrensis blairi (Maravillas red shiner), Gambusia amistadensis (Amistad gambusia) and Gambusia georgei (San Marcos gambusia) are apparently extinct, and three, Oncorhynchus clarki virginalis (Rio Grande cutthroat trout), Hybognathus amarus (Rio Grande silvery minnow) and Gambusia senilis (blotched gambusia) appear to be extirpated from the state. More than 20 percent of the remaining primary freshwater species appear to be in some need of protection.
Interim progress report on a study of the utility of data obtainable from otoliths to management of Humpback Chub (Gila cypha) in the Grand Canyon
(1993-02-05) Hendrickson, Dean A.
Daily growth increments of otoliths of fishes have been useful in many fishery applications since they have been demonstrated to provide a precise method of ageing individuals and reconstructing individual growth and, possibly, movement or habitat histories. These techniques have not been previously applied to humpback chub, but are believed to have considerable potential for providing knowledge of this difficult to sample and little-understood species. Large temperature and water quality gradients apparently traversed by individuals of this species in the Grand Canyon are of a magnitude likely to produce structural and/or chemical signals in the crystalline calcareous otoliths. If so, since otoliths grow by accretion of daily increments (much like trees develop yearly growth rings), and are stable structures, which unlike scales, are not susceptible to reabsorption except in the most extreme conditions, they retain a structural and chemical chronology of habitats occupied. If the relationships of ambient physical and chemical conditions to otolith structure and composition can be described, a chronology of habitat occupancy and growth for individuals could theoretically be reconstructed with daily precision. Such reconstructions of growth rates, birth dates, movement histories, and possibly, birth place (based on chemistry at otolith formation or during early life), could provide extremely valuable life-history information regarding timing of spawning, cohort recruitment, mortality rates, and data on other population parameters critical for management of this endangered species. The feasibility of using otoliths and opercles of humpback chub for age estimation of individuals has been preliminarily investigated by examining otoliths and opercles from a total of 47 juvenile (ages 0 through 1 +)and 43 adult (estimated ages 2- 23) specimens collected in the Little Colorado River (71 specimens) and mainstream Colorado River (19 specimens) at various places in the Grand Canyon between 1988 and 1992. Studies are continuing, and at this point, due to both sample size and numerous other limitations, and ongoing refinements of techniques, conclusions made here are highly preliminary. Structures prepared and examined included opercles of 35 specimens, one asteriscus from each of 47 specimens and a lapillus from each of 56 specimens. Seventeen specimens were evaluated using all three calcareous structures (lapillus, asteriscus and opercle). The sagitta was also examined, but found to be unsuitable for ageing purposes due to its long, delicate form and irregular increments after the larval/juvenile stage. Additional lapilli have been removed from other available specimens, and a complete inventory of specimens available for further study of calcified structures is provided. Studies of micro-spatial variation in chemical composition of selected lapilli is in progress, using the highly accurate proton probe at the Institute of Geological and Nuclear Sciences in Lower Hutt, New Zealand. This method of analysis shows great promise of overcoming what has been indicated in recent literature to be significant inaccuracies of other techniques (Energy Dispersive X-ray diffraction and Wave Length dispersive X-ray diffraction) used in many of the published studies of microspatial elemental analysis of otoliths.
Evaluation of the Razorback Sucker (Xyrauchen texanus) and Colorado Squawfish (Ptychocheilus lucius) reintroduction programs in central Arizona based on surveys of fish populations in the Salt and Verde rivers from 1986 to 1990
(Nongame and Endangered Wildlife Program, Arizona Game and Fish Department, Phoenix, Arizona, USA, 1993-09) Hendrickson, Dean A.
Between 1981 and 1990, more than 11 million hatchery-produced razorback suckers (Xyrauchen texanus) and 750,000 Colorado squawfish (Ptychocheilus lucius) were stocked to historic ranges in the Verde and Salt rivers in Arizona, where natural populations had been extirpated. Efforts to date have focused on broad-scale stockings and general fish surveys to evaluate success. Only 519 razorbacks and 444 squawfish were taken in several years of intensive electrofishing and netting surveys during all seasons throughout large segments of both rivers. Survival of razorbacks appears better in the upper Verde River than in the Salt River, while squawfish appear to fare better in the Salt River than do razorbacks. Most recaptures of either species were taken within weeks of stockings; relatively few individuals were verified to have lived more than a few months in the wild. Large populations of razor backs have not established in mainstreams, although groups have persisted in small, isolated, peripheral habitats where emigration is blocked or impeded. Despite growth to maturity of at least some razorbacks, no evidence of wild reproduction was found. The few squawfish known to have over-wintered in the wild were also taken from a habitat closed to downstream emigration. Proximate impediments to large-scale successful recruitment of stocked individuals to wild populations clearly include predation, principally by exotic flathead catfish and smallmouth bass, and coincident inability of hatcheries to produce large numbers of individuals for release at sizes large enough to escape predation. Despite limited success, it is recommended that stockings of both species continue for two reasons. Large-scale field experiments easily accomplished under the "experimental, non-essential" designation with readily available hatchery fish can elucidate mechanisms of recruitment failure for hatchery stock. These should emphasize experimental analyses of factors affecting mortality, movements and habitat use of stocked fish. Effects of fish condition, transport and stocking stress, size, stocking season, and parasites are other variables which need research. Along with experiments, continued stockings, especially in the case of razorbacks, even with low recruitment rates, appear very likely to contribute to establishment of long-lived populations, and are therefore recommended for both species. Stockings should be as extensive as possible, and focus on releases to closed, peripheral riverine and reservoir habitats (e .g. isolated backwaters), preferably with low or reduced predator populations. While direct stocking of larger individuals would likely increase survival rates in the wild, absolute numbers stocked would remain small given existing facilities . Stockings of far greater numbers of small individuals to such isolated, "wild" habitats and subsequent "wild" growth there prior to release, via either natural or artificial mechanisms, to larger, adjoining habitats, will likely prove to be the most economical and successful approach to establishing multiple, new populations oflong-lived individuals. Recommendations for immediate habitat management actions for both species include manipulations of predator populations and maximization of availability of backwater habitats. A broad-scale, annual field monitoring effort should continue, but most importantly the program should shift to emphasize experimental research. Effectiveness of the reintroduction program could be greatly improved by high-level administrative adjustments with particular attention to development of program objectives, coordination among production, research and monitoring components and frequent evaluation of progress toward objectives.
Final Project report - Interim progress report on a study of the utility of data obtainable from otoliths to management of Humpback Chub (Gila cypha) in the Grand Canyon
(1997-06-13) Hendrickson, Dean A.
This study was initiated with the objective of studying various aspects of the physical and chemical structure of otoliths of humpback chub from the Grand Canyon of Arizona, and primarily from the Little Colorado River (LCR). These studies were to shed light on the utility of otolith studies for improving knowledge of the life history of this endangered species, and to evaluate the potential application of these techniques to questions posed by resource managers. Whole fish specimens, skeletons, or preserved heads of specimens were provided to the author by a diversity of Arizona Game and Fish field crews who collected from 1989 through 1993. The author, with assistance of Dr. Ed Brothers, extracted, prepared and examined otoliths. Data analysis and reporting was the sole responsibility of the author. Specifically, the study was to obtain age estimates (years of age) from otoliths of 50 selected skeletonized adult specimens of Gila cypha collected from the Grand Canyon by Arizona Game and Fish Department in 1989 and 1990. It was also to obtain age estimates (days of age) for 100 selected young-of-the-year (y.o.y.) Gila cypha collected during the same and subsequent years. Age estimates for y.o.y. were predicated on the assumption that increments counted in the otoliths were deposited daily, and that increment counts could thus be translated to days of life since the date of first increment formation (generally within the first few days following spawning). Since that hypothesis had not been specifically tested in this species, the study also was to test the hypothesis that increments form on a daily basis, both in the field and in hatchery experiments. Since at least some humpback chub appear to move across a typically strong thermal gradient at the interface of mainstem Colorado River (MCR) waters and the discharge of the LCR, which is generally much warmer than MCR, it was hypothesized that this transition might lead to the formation of marks, both physical and chemical, in otoliths and that these marks might be used to reconstruct individual life histories with respect to timing of this inter-river movement. Though studies conducted since initiation of the present study {9017} have recently made significant contributions toward documentation of movements of adult humpback chub in the mainstem Colorado, still very little is known of movements of y.o.y. It had been hypothesized that if swept out of the LCR into the mainstem Colorado, the transition might be lethal or have other deleterious impacts on y.o.y. survival and growth. A mark in otoliths that unambiguously conveyed information about extent and timing of movements across this inter-river interface, could thus be valuable in furthering understanding of population dynamics and movements. It was thus proposed to search for such marks in otoliths and to conduct experiments to study the effects of temperature changes on otolith structure. The original study design also called for an analysis of the feasibility of determining annual growth period duration from otoliths of post young-of-the-year individuals of Gila cypha for all growth periods throughout the life of specimens. At the time of study design, there was considerable discussion and application of chemical analyses of otoliths in the literature of fishery management and stock identification. Studies at this time indicated considerable promise for the techniques, and likely applicability to reconstruction of detailed individual life histories of humpback chub. It was hypothesized that individuals that moved across the MCR-LCR temperature and water quality gradient would deposit a chemical/structural signal in their otoliths that reflected this transtion from one river to the other. Since the temporal structure of otolith deposition and specimen birth date could be recovered from the otoliths as well, the absolute date of the movement event, and fish size at the time, might be accurately recoverable as well. It was therefore proposed to carry out analyses of micro-spatial (=chronological) variation in elemental composition in otoliths of 20 selected individual Gila cypha specimens from the Grand Canyon for evaluation of the utility of such techniques for reconstruction of movement history of individuals. In addition it was hoped to compare total elemental composition among otoliths of 5 selected individual specimens of young-of-the-year Gila cypha captured in the Little Colorado River, otoliths of 5 hatchery-reared young-of-the-year Gila cypha, and otoliths of 5 selected Gila cypha suspected or known to have moved between the Little Colorado River and mainstem Colorado River in the Grand Canyon as a means of investigating the effect of these diverse environments on otolith composition. An accidental spill of isotopes into the LCR drainage {9018} was thought to potentially provide isotopic signatures in otoliths. If some of the isotopes characteristic of the spill were found in otoliths, their presence might serve as an unambiguous marker indicating time spent in the LCR. It was therefore proposed to determine the isotopic composition of a subsamplc of the same (or comparable) specimens used for microchemical composition studies. Since otolith isotopic composition had been indicated in other studies tu he highly correlated with ambient temperature, isotopic compositional changes during the temporal sequence of otolith deposition thus might also reflect inter-river transitions. Specimens from experiments designed to determine the effects of ambient temperature on otolith increment deposition were therefore to be examined for isotopic composition as well in an attempt to better understand the effect of temperature on isotopic composition of otoliths. In the course of these studies a bibliography of literature relevant to methods and problems of estimating age and growth of Gila cypha and chemical composition of otoliths as related to application of otolith chemistry to reconstruction of the environmental history of individuals was compiled and is provided with this report. Though this bibliography can hardly be claimed to he comprehensive since the literature in this field has become very extensive, it should serve as a starting point for future researchers interested in otolith studies. Finally, the appendices of this report provide an inventory of all specimens of Gila cypha from the Grand Canyon used (and not used) in this study, and the earlier interim report on early results from this study (less the bibliography, which has been updated in this report). Some questions answered in that report, such as comparisons of ageing techniques using the asteriscus and opercle, are not reiterated here, and the figures provided there amply illustrate all otolith structural features and variations discussed in this report.
A New State Record for Percina phoxocephala (Percidae) in Northeastern Texas
(1999) Dries, Laurie A.
Fishes of the Río Fuerte, Sonora, Sinaloa and Chihuahua, México
(Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, Monterrey, Nuevo León, México, 2002-11-10) Hendrickson, Dean A.; Varela Romero, Alejandro
The Rio Fuerte drains 33,835 km2.of the Sierra Madre Occidental of the Mexican states of Chihuahua, Sinaloa, Durango, and Sonora. Its tributaries pass through Barranca del Cobre (Copper Canyon) as they drop from headwaters as high as 2,808 m above sea level to the Mar de Cortes (Gulf of California). Its headwaters interdigitate closely with east-flowing tributaries of the Rio Conchos, an important tributary of the Rio Bravo (Grande), and interior drainages of Chihuahua and Durango, such as the Rio Nazas. The Fuerte shares its fish fauna with these neighboring drainages, and has no endemics. Northernmost tributaries are relatively arid, but southern tributaries drain sub-tropical areas with much higher rainfall. Dams and diversions now block movements of many marine fish species that used to move far upstream, and more are in construction or planned. Large river fish habitats at lower elevations have been converted almost entirely into canals and the natural mainstream channel now carries only minimal or highly modified discharges, often contaminated by agricultural runoff. At higher elevations, fish habitats have been severely impacted by logging and grazing. Logging development continues, recently expanding from traditional conifers to lower-elevation oaks. Exotic fishes have had, or surely will have, broad impacts on the native fauna through predation, competition and hybridization. Tilapias from Africa are widely established now, as are several centrarchids that will undoubtedly impact on the native cichlid (Cichlasoma beani), cyprinids, catostomids, poeciliids, and others. While not well studied taxonomically, the basin's native catfish, closely related to Ictalurus pricei, is now broadly hybridizing with introduced channel catfish (I. punctatus). At higher elevations, the beautiful native Mexican golden trout is very likely to hybridize with rainbow trout being widely introduced for fish culture. El Rio Fuerte drena 33,835 km2 de la Sierra Madre Occidental en los estados de Chihuahua, Sinaloa, Durango y Sonora. Sus tributarios fluyen a traves de la Barranca de! Cobre (Copper Canyon) y caen desde las cabeceras de 2,808 m sobre el nivel del mar hacia el Mar de Cortes (Gulf of California). Sus cabeceras interdigitan cercanamente con los tributarios de flujo este del Rio Conchos, un importante tributario del Rio Bravo (Grande) y drenajes interiores de Chihuahua y Durango como el Rio Nazas. El Fuerte comparte su fauna de peces con estos drenajes vecinos y no presenta endemicos. Los tributarios norteños son relativamente aridos, pero los tributarios sureños drenan areas subtropicales con mayor regimen de lluvias. Las presas y canales, que bloquean ahora el movimiento de muchas especies de peces marinos que lo usaban para remontar el rio, siguen en construcción y planeación. Los habitats de peces de rios grandes en bajas elevaciones han sido convertidos en canales y el canal principal natural ahora mantiene descargas minimas o altamente modificadas, frecuentemente contaminadas por desechos de la agricultura. A grandes elevaciones, los habitat de los peces han sido impactados severamente por la tala y el pastoreo. Los desarrollo madereros continuan y recientemente se han expandido de las tradicionales coniferas a los encinos de mas baja elevaci6n. Los peces exóticos tienen o seguramente tendran grandes impactos sobre los peces nativos a traves de la depredación, competencia e hibridación. Las tilapias de Africa estan ahora ampliamente establecidas al igual que varios centrarquidos, que indudablemente impactan sobre el ciclido nativo (Cich/asona beani), ciprinidos, catost6midos, pecilidos y otros. Aunque no esta bien estudiado taxonomicamente, el bagre nativo de la cuenca, cercanamente relacionado a Ictalurus pricei, esta ahora hibridizandose ampliamente con el bagre de canal introducido. A grandes elevaciones, la hermosa trucha dorada Mexicana nativa, es muy posible que hibridice con la trucha arcoiris, que ha sido ampliamente introducida como pez de cultivo.
Extreme Catfish
(North American Native Fish Associaton, 2004) Sneegas, Garold; Hendrickson, Dean A.
Below the city of San Antonio Texas lies a vast aquifer known as the Edwards (Balcones Fault Zone) Aquifer. Two rare and unusual catfish reside in the aquifer, Satan eurystomus, the widemouth blindcat and Trogloglanis pattersoni, the toothless blindcat. They are the only known troglobitic catfish in the United States. The only specimens of both species ever collected have come from deep (1,200' to 1,500') artesian wells within the city of San Antonio itself and parts of southern Bexar County.
Peces y Aguas Continentales del Estado de Tamaulipas, México
(Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, Monterrey, Nuevo León, México, 2004-09) Contreras-Balderas, Salvador; Lozano-Vilano, Ma. de Lourdes; García-Ramírez, María Elena; García De León, Francisco Javier; Gutiérrez Tirado, Delladira
El estado de Tamaulipas, México, cuenta con una fauna de peces nativos típicamente de agua dulce que consiste de 20 familias, 5O géneros y 85 especies, de las cuales Neárticas-Primarias 23 géneros y 49 especie, Neárticas-Secundarias cinco géneros y ocho especies, Neotropicales-Primarias, un género y dos especies, Neotropica les-Secundarias siete géneros y 19 especies, Periféricas son nueve familias, doce géneros y 16 especies. La NOM 059-ECOL-2001 categoriza en Tamaulipas 19 especies (mas l que será propuesta) debidas a diversos impactos del desarrollo, siendo tres en peligro, once amenazadas, dos de protección especial, y tres probablemente extintas. Las especies introducidas pertenecen a cuatro familias, trece géneros, y 24 especies. Siete especies son nativas en el norte de Tamaulipas, y exóticas en el sur. Las causas de riesgo son especies exóticas, reducción de hábitat, contaminación, aguas residuales, basuras, lluvia ácida, erosión acuática y terrestre, ensalitramiento, abatimiento del nivel de agua y desecado de acuíferos, ríos, lagos; alteraciones de hábitat (represamiento, canalización, desecamiento de humedales, dragado, cortes carreteros); deforestación, y algunos fenómenos naturales, como sequía, incluyendo la reducción de población de algunas especies, naturalmente raras o localizadas. Un desarrollo no sustentable está matando los ecosistemas riverinos de Tamaulipas.
Biodviersityof Mexican Trout (Teleostei: Salmonidae: Oncorhynchus): Recent findings, conservation concerns, and management recommendations
(Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, Monterrey, Nuevo León, México, 2004-09) Mayden, Richard L.
Until very recently the diversity of trout in Mexican rivers of the Sierra Madre Occidental has been very poorly understood and only the Rainbow Trout, Oncorhynchus mykiss, and the Mexican Golden Trout, 0. chrysogaster, have been recognized. Recent efforts in the last decade by a binational organization of scientists and laypersons interested in the diversity and conservation of Mexican trout, Truchas Mexicanus, have revea led considerable diversity within the river systems of the Pacific Slope south to the Rio Acaponeta . These trout forms are highly differentiated and distinctive, and are considered native to these high-elevation river systems in pine-dominated forests. The increased occurrence of trout growout facilities and hatcheries within the range of these native Oncorhynchus and the escapes from these facilities threaten the native trout diversity through both introgressive hybridization and through resource competition, end products already known to occur in other trout populations in the other areas of North America exposed to exotic hatchery trout. Other threats to the native and previously unknown trout biodiversity in Mexico include timber harvesting, some pollutions associated with these activities, and siltation of critical habitats. Recommendations are provided to aid in the safe management and protection of this diversity which center around the future use of sterile trout in growout facilities and the use of undisturbed buffer zones along streams. The divergence observed in forms of Mexican trout is equivalent to the levels of divergence found between currently recognized subspecies of trout in the Rainbow and Cutthroat trout groups. Upon review of the diversity and divergence known to exist in these groups and our current understanding of conceptualizations of species, it is argued that the recognition of subspecies within these highly diverse trout lineages is inconsistent with the natural evolutionary history of these groups. The long-term use of the Biological Species Concept for these species is argued as not only inappropriate but an inadequate and illogical characterization of diversity. The logical consequences of hanging on to this concept as the operational and theoretical framework of trout diversity would necessitate the synonymization of all Rainbow and Cutthroat trout taxa as subspecies because of the known propensity of these groups to demonstrate introgressive hybridzation in some areas. These subspecies are considered va lid evolutionary lineages that are demonstrate divergence at morphological, genetic, and ecological characters that are well known to many trout taxonomists and biologists. All of these therefore qualify as Evolutionary Species that are easily diagnosable under the Phylogenetic Species Concept and should be recognized as valid species.
Fishes of the continental waters of Tamaulipas: diversity and conservation status
(Oxford University Press, 2005) García de León, Francisco J.; Gutiérrez Tirado, D.; Hendrickson, Dean A.; Espinosa-Pérez, Héctor
With an origin dating back 400 million years, fishes represent the most ancient group of vertebrates (Helfman et al. 1997). They are also the most diverse, with more than 25,000 species. Of the more than 2200 species known from Mexico, about 500 live in freshwater. The Mexican Official Norm NOM-059-ECOL-2001 lists only 186 fish species among the 1515 vertebrates "At Risk" in Mexico (SEMARNAT 2002; see chapter 4). Fishes thus account for only 12.3% of all listed species in Mexico, compared to 30.8% for reptiles, 24.8% birds, and 19.5% mammals. Why are so few fishes listed in Mexico? The answer probably has little to do with actual conservation status and more to do with other factors. First, the great taxonomic diversity of fishes renders any comprehensive evaluation of their conservation status quite daunting. Not only are fishes more than half of all vertebrate species, but new species continue to be described every year (Helfman et al. 1997). Because fishes live only in water, they are more difficult to observe than are most other vertebrates. Finally, fishes show a high degree of intraspecific phenotypic variation that makes them highly sensitive to environmental factors and often difficult to identify (Allendorf et al. 1987; Allendorf 1988). Fishes are important to humans because they represent an important source of food. Their commercial and recreational value has led to fish farming on an industrial scale, both for easy exploitation and as a means to recover overharvested natural populations. Scientific interest in fishes is also considerable. Those species easy to manage in captivity can be used in laboratory experiments. Additionally, freshwater fishes in particular can be used as biogeographic indicators, contributing important information to our understanding of the history of river basins and serving as indicators of aquatic ecosystem health. Though their aquatic habitats perhaps make wild fish populations more difficult to study than terrestrial organisms, they clearly deserve greater emphasis in the field of biological conservation. The northern part of Mexico harbors 3 aquatic ecoregions known as the Sonoran, ChihuahuanPotosian, and Tamaulipan regions (ContrerasBalderas 1969). The Tamaulipan ecoregion is located between the Sierra Madre Oriental and the Gulf of Mexico, within the Mexican states of Coahuila, Nuevo Leon, and Tamaulipas (CONABIO 2000); the last of these states is the focus of this chapter. To the north, Tamaulipas is bounded by the Rio Grande (Rio Bravo), which marks the border with Texas. To the west, Tamaulipas is bounded by the Mexican states of Nuevo Leon and San Luis Potosi, to the east by the Gulf of Mexico, and to the south by the states of Veracruz and San Luis Potosi (fig. 7.1). The geomorphology of watersheds influences species richness (Eadie et al. 1986). For example, river discharge is a direct measure of availability of habitat for freshwater fishes (Livingstone et al. Patterns of Species Diversity and Ecological Importance of Natural Ecosystems 1982), and there is a positive correlation between species richness and surface area of a river basin (Horwitz 1978). Thus, anthropogenic alterations of a watershed can drastically reduce its associated biological diversity (Sheldon 1987). Decreases in total habitat area and habitat fragmentation (typically a result of dams) occur conjunctively, reducing not only the size of many populations but also the potential for dispersal and genetic flow (Frankham et al. 2001). Additionally, diversion canals linking once separate waterways, and the introduction of exotic species, are both leading to homogenization of aquatic faunas (Sheldon 1988). Due to the rapid increase in hu.man populations, northern Mexico has experienced major, humaninduced alterations and fragmentation of its watersheds and associated changes in the distribution of taxa and loss of biodiversity (Contreras-Balderas 1978). Clearly, any conservation effort requires an inventory of the ichthyofauna using a taxonomic and biogeographic approach, focusing on documenting and maintaining overall biodiversity, but also including the rare and endangered species. The specific objectives of the study described in this chapter were to evaluate the diversity of freshwater fishes in Tamaulipas, to characterize each watershed and analyze the status of its ichthyofauna, and to determine the level of anthropogenic impact on freshwater fish communities statewide. We begin with a description of the watersheds of Tamaulipas, then present a synthesis of the state of knowledge of taxonomy, biology, genetics, evolution, exploitation, and conservation of fishes in Tamaulipas and provide the first list of freshwater fishes assembled for the state.
Conservation of the Conchos Trout: a white paper on history of its discovery, report on its status, and an urgent plea for action
(Dean A. Hendrickson, 2006-04-13) Camarena Rosales, Faustino; Cutter, Ralph F.; De Los Santos Camarillo, Ana Belia; Espinosa Pérez, Héctor; García de León, Francisco; Hendrickson, Dean A.; Kuhajda, Bernard; Mayden, Richard L.; Neely, David A.; Pfiefer, Frank; Propst, David L.; Ruiz Campos, Gorgonio; Tomelleri, Joseph R.; Varela Romero, Alejando
A broad-scale survey of potential trout habitats in upper tributaries of the Río Conchos of Chihuahua, México resulted in the re-discovery in 2005 of a long-lost native, endemic, and now endangered, undescribed trout species that we call the “Conchos Trout.” We are currently in the process of scientifically describing this rare trout, the only native Mexican trout known from an Atlantic drainage. Our extensive field efforts to date clearly indicate that this species was formerly much more widely distributed historically. Though surveys should continue, our extensive field surveys found only one small isolated and extremely vulnerable population, leaving us less than optimistic that many other, if any, additional populations will be found. Persistence of this new critically endangered endemic Conchos Trout clearly requires rapid conservation action. Our consensus expert opinion is that we cannot over-emphasize the urgency of protection for this critically endangered population of this unique trout, and so we have produced this “white paper” in hopes that it might encourage others to join us in initiating appropriate conservation programs. The potentially viable population is restricted to a short reach of a very small stream where it and another newly discovered, undescribed fish species, a sucker (and likely another unique taxon), could be relatively easily protected, studied and managed. Additionally, adjoining arroyos where the species recently occurred offer the possibility of restoring native fish populations to them following appropriate protection and habitat restoration efforts. All members of our highly qualified and diversely specialized, binational “Truchas Mexicanas” team stand prepared to join collaborators and invest personal resources in hands-on actions to help this new species persist. We recommend immediate establishment of a small reserve centered around currently occupied habitat and adjacent streams having suitable habitat, combined with education and compensation of local residents for their cooperation with reserve management. We recognize that we are largely ignorant of the local political and cultural systems via which conservation actions will have to proceed and are limited with regard to our ability to raise funds. We thus hope that readers of this white paper will add their financial and in-kind support and additional expertise to help us conserve the Conchos Trout!
Conservation of Mexican native trout and the discovery, status, protection and recovery of the Conchos trout, the first native Oncorhynchus of the Atlantic drainage in Mexico
(Dirección de Publicaciones, Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, Monterrey, Nuevo León, México, 2007) Hendrickson, Dean A.; Neely, David A.; Mayden, Richard L.; Anderson, K.; Brooks, James E.; Camerana-Rosales, Faustino; Cutter, Ralph F.; Cutter, Lisa; De Los Santos Camarillo, Ana Belia; Ernsting, Guy W.; Espinosa-Pérez, Héctor; Findley, Lloyd T.; Garcia de León, Francisco J.; George, A. L.; Hatch, John; Kuhajda, Bernard R.; Mayden, Kyle E.; McNyset, Kristina M.; Nielsen, Jennifer L.; Pfeiffer, Frank W.; Propst, David L.; Ruiz-Campos, Gorgonio; St. Clair, E.; Tomelleri, Joseph R.; Varela-Romero, Alejandro
The Northwestern Sierra Madre Occidental of Mexico is a rugged mountain range covering portions of Sonora, Chihuahua, Durango and Sinaloa, and is drained by multiple Pacific Slope Rivers to the west and the Casas Grandes, Conchos, and Nazas to the east. The overall area is topographically, climatically and biotically diverse, ranging from endorheic basins (Casas Grandes) to mountainous areas elevations up to 3348 m, average mean temperatures from 10-20°C and precipitation from 250-1100 mm/yr. The region is also geological complex that, combined with these other variables, provides a great diversity of both aquatic and terrestrial habitats conducive to both biotic endemicity and diversity. The overall diversity of the region has contribiited to the recent listing of this region by Conservation International as one of six new high-priority biodiversity hotspots. Our understanding of the aquatic and terrestrial biodiversity of this region, however, is poor and in urgent need of rapid investigation by collaborative communities. The combination of an incredibly rugged landscape, drug and bandit activities and indigenous peoples that have not always been welcoming to visitors has resulted in a general paucity of roads in the region, and the lack of access has limited inventory studies. Recently, however, access to the region has changed dramatically and many of the areas are now accessible enough for logging, mining, and agriculture practices, all exerting extreme pressures in some areas on the biodiversity. In addition to human-induced changes to these diverse ecosystems, impacts of invasive aquatic species are becoming more and more apparent, and the potential for severely reducing population sizes of species or their extirpation or extinction is real. While several invasive or exotic species are identified as potentially destructive to these communities, the exotic Rainbow Trout (Oncorhynchus mykiss) that is derived from hatcheries or culture facilities within the region represents one of the most critical threats to the aquatic and semi-aquatic biodiversity. The native trout of mainland Mexico represent the southern- most salmonids, and are at imminent risk of introgression and/or replacement by feral Rainbow Trout, Oncorhynchus mykiss. Our recent survey efforts have expanded the known diversity and ranges of each of several distinct forms, which we feel represent valid species. We discuss our discovery of multiple new species from the Sierra Madre Occidental and focus on a new species of trout restricted to the upper Conchos drainage, the first native species of Oncorhynchus known to occupy the Atlantic Slope in Mexico. Many of these taxa are restricted to small areas of intact habitat in headwater areas of high-elevation streams, and are at risk from a suite of human-associated perturbations, emerging diseases, and introduced species. These fishes occupy unique habitats, and represent a diverse portion of the Mexican montane ichthyofauna. The habitats on which they depend support a wide range of other aquatic organisms, most of which are grossly understudied. The discovery of the Conchos Trout derived primarily by GARP niche modeling of a subset of localities of previously sampled undescribed native Mexican trout, provides only a snapshot of the biodiversity awaiting to be discovered in this region. The rugged landscape of the Sierra Madre Occidental simply precludes routine sampling at easily accesible locations of streams and most sampling locations require time-intensive access. In an effort to rapidly assess the biodiversity of rivers of this region we employed this method to aid in predicting the most suitable and highly probable Mexican trout niches in the region. This method offered highly efficient and powerful results that not only predicted the occurrence of a previously unknown trout in the upper Rio Conchos but also provided excellent predictions of available habitats in drainages where previously unknown trout have been discovered by the Truchas Mexicanas team in the last nine years. Multiple threats exist to the biodiversity of the northern Sierra Madre Occidental, including uncontrolled introductions of exotic and invasive species, emerging diseases such as whirling disease, Myxobolus cerebralis, infectious pancreatic necrosis (IPN), iridioviruses and pathogenic water mold, Saprolegnia ferax, land-use practices leading to habitat degradation via overgrazing, logging, deforestation and road construction, increasing human population growth, over-fishing or overharvesting of aquatic resources and global climate cliange reducing surface and ground water in the area and creating environments more conducive to the spread of invasive species, congregated and dense human populations, and emerging diseases. Immediate actions need to be developed to aid in public education as to the threats to these ecosystems, protection of areas, assessment of diversity, and sustainable development throughout the region that incorporates a likely highly successful ecotourism system for the region.
General Fish Surveys on Selected Texas National Guard Properties: Camp Bowie, Camp Mabry, Camp Maxey, Camp Swift and Fort Wolters
(2007-12) Hendrickson, Dean; Cohen, Adam
The Texas Natural History Collection of the Texas Natural Science Center was contracted to conduct a fish survey on five Texas Military Forces facilities in Texas, including: Camp Mabry (Travis County), Camp Swift (Bastrop county), Camp Bowie (Brown county), Camp Maxey (Lamar County), and Fort Wolters (Parker County). This is the second fish survey completed for the properties. The first was completed by the Texas Parks and Wildlife Department (TPWD) in 1995 and included a total of 27 species, representing eight families collected from the five properties. During the course of this survey, 39 species were collected, representing 10 families. New records include Aplodinotus grunniens, Carpiodes carpio, Cyprinus carpio, Esox niger, Etheostoma parvipinne, Lepisosteus oculatus, Minytrema melanops, Notropis texanus, Percina macrolepida, Percina carbonaria, Pomoxis nigromaculatus, and Pylodictis olivaris. Species which we were not able to re collect include Astyanax mexicanus and Pimephales promelas. Three species were widely distributed and collected at every base: Micropterus salmoides, Lepomis macrochirus, and Gambusia affinis. The most species-rich family was Centrarchidae and within that, Lepomis was the most species-rich genus with eight species. Consistent amongst the five bases, diversity ranked highest in perennial streams, lowest in lentic habitats, and intermediate in intermittent streams.
Status Survey of Devil´s River Minnow in Historic Range with Emphasis on Coahuila, Mexico
(Pronatura Noreste, Monterrey, Nuevo León, México, 2007-12-15) Contreras-Arquieta, Alberto; Lozano-Vilano, Ma. de Lourdes
English - A study was carried out to document the current status of the Devil's River Minnow, Dionda diaboli Hubbs and Brown, 1956, in northern Coahuila, Mexico. Three field trips were carried out with a total of 49 localities sampled, documenting presence of 49 species of the 54 species previously registered in the area, which are from 25 genera and 12 families. Six localities were previously known for this species in Mexico, and those historical records were obtained and entered into a geographic information system. The Devil's River Minnow was found in only one of the historic locations, in the Río San Juan under the bridge on the Múzquiz - Boquillas del Carmen highway, Múzquiz, Coahuila. Habitat condition, water quality, aquatic vegetation of all historic locations, as well as an analysis of the fish community, were evaluated. We observed that temperature oscillates between 23.9 and 27.8 ºC, the salinity between 0.14 and 0.17 ppm, the dissolved oxygen between 64.9 and 90%, the pH between 7.14 and 8.03, the turbidity below 30, with little organic matter, as shown by the results for nitrites, nitrates, sulfates, calcium and magnesium. It was found that the causes of the disappearance of Dionda diaboli, in the other localities, is due to the presence of exotic species, alteration of the habitat, decrease in water level and runoff, siltation by sediments and probably due to changes in the trophic structure of the fish community. Spanish - Se realizó un estudio para conocer el estado actual de la carpa diabla, Dionda diaboli Hubbs y Brown, 1956, de la región Norte del Estado de Coahuila, México. Se efectuaron 3 salidas de campo con un total de 49 localidades visitadas, de las cuales se reportan 49 especies de las 54 registradas en la zona, repartidos en 25 géneros y 12 familias. Seis localidades son registradas de esta especie en México, con los registros obtenidos y los registros históricos se elaboró un sistema de información geográfica. Solo fue posible observar a la carpa diabla en una de las localidades históricas. En Río San Juan bajo puente, carretera Múzquiz – Boquillas del Carmen. Múzquiz, Coahuila. Se evaluó la condición de hábitat, calidad de agua, vegetación acuática de las localidades históricas así como un análisis de la comunidad de peces. Entre los parámetros ambientales observamos que la temperatura oscila entre 23.9 y 27.8 ºC, la salinidad entre 0.14 y 0.17 ppm, el oxigeno disuelto entre 64.9 y 90 %, el pH entre 7.14 a 8.03, la turbidez inferior a 30, con escasa materia orgánica, como lo muestran los resultados de nitritos, nitratos, sulfatos, calcio y magnesio. Se encontró que las causas de desaparición del Dionda diaboli, en las otras localidades se debe a la presencia de especies exóticas, alteración del hábitat, disminución del nivel de agua y escorrentía, asolvamiento por sedimentos y probablemente por los cambios en la estructura trófica de la comunidad íctica.
An Annotated Checklist of the Freshwater Fishes of Texas, With Keys to Identification of Species
(Texas Academy of Science, 2008-07) Hubbs, Clark; Edwards, Robert; Garrett, Gary
Forty-nine families and 268 species of fishes are known to inhabit the freshwaters of Texas. We report on the distribution and status of these fishes and provide a key to their identification. Of the native fishes originally found in Texas, five taxa, Cyprinella lutrensis blairi (Maravillas red shiner), Notropis orca (phantom shiner), N. simus simus (Rio Grande bluntnose shiner), Gambusia amistadensis (Amistad gambusia) and G. georgei (San Marcos gambusia) are apparently extinct, and four, Hybognathus amarus (Rio Grande silvery minnow), Notropis simus pecosensis (Pecos bluntnose shiner), Oncorhynchus clarki virginalis (Rio Grande cutthroat trout) and Gambusia senilis (blotched gambusia) appear to be extirpated from the state. Over 40 percent of the remaining primary freshwater species are of conservation concern and in some need of protection.

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