Ichthyology

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An Alternative Shelving Arrangement for Natural History Collection Objects to Optimize Space and Task Efficiency
(Allen Press, 2019-09-01) Cohen, Adam; Hendrickson, Dean; Casarez, Melissa
A taxonomic and alphabetic arrangement (TAA) of objects on shelves has prevailed in fluid-preserved natural history collections while they were managed by scientists for their own research. Now most collections are databased and internet-accessible to facilitate very different forms of research accomplished remotely by researchers who require less physical access to specimens. The collections staff who make those data available struggle to manage collection growth with limited space and budgets, while demands on them are increasing, necessitating task and space-efficient collection management solutions. We describe an alternative arrangement of objects based on their size and catalog number (OCA) that capitalizes on modern databases. Our partial implementation of this system facilitated pragmatic between-system comparisons of space use and staff time required for routine tasks. Our OCA allows 17% more jars to be stored in a given space than a TAA (not counting spaces left for growth), but adjusting vertical spacing of shelves could increase that to 115%. Ten of 15 staff tasks were more efficiently accomplished in the OCA section of the collection, and we propose ways to improve efficiency for three of the four tasks for which the TAA outperformed the OCA.
American Eel in Texas – what we do, don’t, and need to, know
(2016-01-22) Hendrickson, Dean A.; Cohen, Adam E.; Labay, Ben; Garrett, Gary P.; Casarez, Melissa; Martin, F. Douglas
American Eel is undoubtedly one of the most studied freshwater fishes of North America. Many recent discoveries have added new insights that re-write important aspects of the “text book” knowledge of the species’ complex life history in ways that could have significant impacts on management. Despite all of this new information, debate about the species’ conservation status continues, and new threats, such as continued habitat loss and major clandestine fisheries driven by extremely high value in the global market, have further complicated management. Though USFWS recently decided that the species does not merit listing as “Endangered,” in 2012 Canada changed that country’s assessment of the species’ status from “Special Concern” (since 2006) to “Threatened” and IUCN upped its classification in 2013 to “Endangered.” Ontario has considered it “Endangered” since 2007. All U.S. Atlantic states vowed to work together to produce, in 1999, the American Eel Benchmark Stock Assessment, which mandated each state conduct standardized monitoring of recruitment and later, mandatory catch and effort monitoring. Given all that activity and data generation, it is remarkable that still so little is known about the populations of the Gulf of Mexico (GOM) and its tributary rivers that making any management decisions in that large, neglected part of the species’ range is virtually impossible. The Fishes of Texas Project team has been collating and improving the limited and scattered data on occurrences of the species in the region and concludes it important to promote a broad scale (Gulf of Mexico) collaborative community effort to acquire and share data and carefully curated specimens and, hopefully, develop a GOM-wide collaborative research and management plan like that implemented by Atlantic states. Here we’ll review the literature and state of knowledge about the species in Texas and GOM, and suggest ways to begin work toward such an effort.
American Eels in Texas – a review of what is known, what is being done to learn more, and how you can help
(2017-11-08) Hendrickson, Dean A.
This presentation reviews the current status of knowledge about the American Eel, its conservation status and distribution in Texas, and work in progress to learn more about the species in Texas.
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.
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.
Aquatic Ecology: Coleto Creek Project
(Central Power and Light Company, 1976-10) Murray, Scott; Jinnette, Scott; Moseley, Frank
No formal abstract in this document. The report includes data from 1975 to 1976 collected from six sites on Coleto Creek in DeWitt, Goliad and Victoria Counties in Texas. Biological data are included in tables and include mostly fish, but also arthropods.
Assessing Historical Fish Community Composition Using Surveys, Historical Collection Data, and Species Distribution Models
(Public Library of Science, 2011-09-22) Labay, Ben J.; Cohen, Adam E.; Sissel, Blake; Hendrickson, Dean A.; Martin, F. Douglas; Sarkar, Sahotra
Accurate establishment of baseline conditions is critical to successful management and habitat restoration. We demonstrate the ability to robustly estimate historical fish community composition and assess the current status of the urbanized Barton Creek watershed in central Texas, U.S.A. Fish species were surveyed in 2008 and the resulting data compared to three sources of fish occurrence information: (i) historical records from a museum specimen database and literature searches; (ii) a nearly identical survey conducted 15 years earlier; and (iii) a modeled historical community constructed with species distribution models (SDMs). This holistic approach, and especially the application of SDMs, allowed us to discover that the fish community in Barton Creek was more diverse than the historical data and survey methods alone indicated. Sixteen native species with high modeled probability of occurrence within the watershed were not found in the 2008 survey, seven of these were not found in either survey or in any of the historical collection records. Our approach allowed us to more rigorously establish the true baseline for the pre-development fish fauna and then to more accurately assess trends and develop hypotheses regarding factors driving current fish community composition to better inform management decisions and future restoration efforts. Smaller, urbanized freshwater systems, like Barton Creek, typically have a relatively poor historical biodiversity inventory coupled with long histories of alteration, and thus there is a propensity for land managers and researchers to apply inaccurate baseline standards. Our methods provide a way around that limitation by using SDMs derived from larger and richer biodiversity databases of a broader geographic scope. Broadly applied, we propose that this technique has potential to overcome limitations of popular bioassessment metrics (e.g., IBI) to become a versatile and robust management tool for determining status of freshwater biotic communities.
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.
Biogeography of Cyprinodon across the Great Plains-Chihuahuan Desert region and adjacent areas
(Desert Fishes Council, 2021) Hoagstrom, Christopher; Osborne, Megan
Cyprinodon is renowned for localized endemism across the North American desert. Competing molecular studies have made elucidating timing of diversification across the desert controversial. Debate has focused on Mojave Desert species, with limited evaluation of other evidence. However, the Great Plains and Chihuahuan Desert harbor more taxonomic diversity and are geographically positioned between the Gulf of México (place of origin for the genus) and Mojave Desert, making them central to understanding the evolution of all desert Cyprinodon. This study is a detailed assessment of evidence from literature spanning geomorphology, climate, and biogeography vis à vis the mtDNA phylogeny for Cyprinodon. Conclusions of Late Miocene-Early Pleistocene diversification are supported across all major clades. Future studies that could improve understanding and address ongoing dilemmas are identified. Importantly, the geography of each clade corresponds to drainage configurations and their evolution through the proposed period of diversification. Eight hypotheses are presented to address major evolutionary events, with emphasis on exploring interpretive challenges within the phylogeny. Broadly, aridity within the Late Miocene apparently facilitated inland invasion of coastal Cyprinodon along the ancestral Brazos River and Río Grande. The following Pliocene warm, wet period enabled survival and range expansion through aridland drainages and into adjacent ones. Mio-Pliocene development of the Río Grande Rift and Gila River drainages, causing inter-drainage transfers, was crucial to range expansion. Development of other Gulf of California drainages (Colorado River, Río Yaqui) played peripheral roles. Climatic cooling in the Quaternary Period evidently caused range contractions for populations living at higher latitudes and elevations. Living Cyprinodon of the desert represent an incredible legacy of Pliocene range expansion memorialized by subsequent persistence of tenacious endemic populations. Human impacts now threaten this legacy.
Changes in fish populations in the Lower Canyons of the Rio Grande
(Chihuahuan Desert Research Institute, 2014) Garrett, Gary P.; Edwards, Robert J.
The Lower Canyons of the Rio Grande suffer from environmental degradation that has negatively impacted native fish populations and their distributions. Macrhybopsis aestivalis (speckled chub), Notropis jemezanus (Rio Grande shiner), Rhinichthys cataractae (longnose dace) and Cycleptus elongatus (blue sucker) populations appear to have suffered recent declines. Although diminished water quantity is likely an important factor in these declines, related changes in channel morphology precipitated by massive stands of Arundo donax (giant reed) and Tamarix sp. (salt cedar) may also be responsible. These invasive exotics have essentially channelized the river, disrupted normal sediment distribution and reduced shallow, low-velocity habitats. Much of the Lower Canyons of the Rio Grande are devoid of sandy sediment and most riffles are now composed of gravel and cobble.
Checklist and Images Documenting the Biodiversity of Johnston Atoll National Wildlife Refuge
(2020-03-21) Rash, Ryan
Included are five pdf files documenting biodiversity on Johnston Atoll National Wildlife Refuge in the Pacific Ocean from June of 2019 through December of 2019. Most images are taken by Ryan Rash, but some were provided to him by others there cohabitating the island at the time. He, and a crew of 4 others were employed to work on the island by the United States Fish and Wildlife Service in an effort to control and document the spread/containment of invasive yellow crazy ants (Anoplolepis gracilipes) and document their effects on native wildlife. The images here were taken by him during his off-time, as a side-project while working on the island. They were compiled and produced into the files provided here in the months after his deployment. The project aimed to record every species of animal and plant, preferably with a photograph sufficient for species determination, but in some cases, as indicated in the included checklist, species were noted without a photograph. In addition to the checklist, images were organized into a collection of four taxonomic presentations: (1) Fish; (2) Birds; (3) Plants; and (4) Herps, Inverts, and Mammals. Within each file, species are sorted alphabetically within their higher taxa, which are also sorted alphabetically for easy perusing. Johnston has a lengthy military history beginning in the early 1930s. Nuclear radiation and harmful chemicals like agent orange were stored there and have leaked out into the environment. These have since been remediated, but sometime in the early 2000s after the military left in 2004, yellow crazy ants infiltrated the island via driftwood—or more likely as incidental passengers on personal vessels hopping between the Pacific remote islands. The crazy ants quickly took over the island, proving especially detrimental for the resident red-tailed tropicbirds (Phaethon rubricauda) that nest on the ground. The ants began swarming the nesting tropicbirds and their chicks, spraying them with formic acid expelled through their acidopores. Tropicbirds, after being sprayed repeatedly in the eyes, were blinded and eventually perished only to be consumed by the ants. In 2010, U.S. Fish and Wildlife Service researchers visited Johnston and discovered the infestation. They ended up creating a treatment plan later that year and sent out the first Crazy Ant Strike Team (CAST), and ever since there has been a crew of ~5 people on the island at all times (apart from hurricane evacuations). Thankfully, the pesticide treatment worked and yellow crazy ants haven’t been detected since December of 2017, but extensive monitoring has continued in order to be completely sure of their eradication. The last step in deeming the island free from crazy ants is bringing scent dogs out to survey for the formic acid scent trail, as the ants could have possibly taken up residence in underground plumbing and electrical conduit. This will hopefully occur at the end of this year. If everything goes to plan, the dogs won’t find anything and our confidence in eradication will be more well-founded. Johnston Atoll at the time of the infestation was home to the largest red-tailed tropicbird colony in the world with over 5,000 active nests. The entire island was just surveyed a month ago and that number has increased to over 10,800 active nests! It was important to save this atoll from the infestation, as it’s the only landmass for over 800,000 square miles of ocean and is one of the, if not the most, isolated landmasses in the world, and a key nesting/stopover point for many bird species.
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.
Clark Hubbs and the Fishes of Texas
(0000-00-00) Unknown
The Clark Hubbs Professorship in Zoology
(0000-00-00) University of Texas at Austin
Clark Hubbs Student Research Award: A Synoptic Vita of his Lifetime Achievements in Fisheries Biology for Which this Award is Honored
(2005-01) Texas Chapter of the American Fisheries Society
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.
Conservation of Texas freshwater fish diversity: selection of Species of Greatest Conservation Need
(Texas Parks and Wildlife Dept, 2020) Birdsong, Timothy; Garrett, Gary; Bean, Megan; Bean, Preston; Curtis, Stephen; Fleming, Paul; Grubh, Archis; Lutz-Carrillo, Dijar; Mayes, Kevin; Robertson, Clint; Robertson, Sarah; Schlechte, Warren; Smith, Nathan
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 status assessment of the endangered Mexican Blindcat, Prietella phreatophila
(2017-07-15) Dugan, Laura E.; Hendrickson, Dean A.; Hernández-Espriú, Antonio; Garrett, Gary P.; Cohen, Adam E.; Wolaver, Brad; Smith, Ryan
Discovery of the Mexican blindcat, Prietella phreatophila, in Texas in 2016 generated interest in the species, which had previously only been known from Mexico but is listed as a foreign endangered species in the US. Consequently, an effort was undertaken to conduct a conservation status assessment of the fish using standardized methods developed by NatureServe. These assessments aim to determine the extinction risk of species and produce conservation ranks, which can be used to inform listing statuses and policy decisions and to determine conservation priorities. The rank is determined by assessing factors in three main categories: rarity, threats, and trends. Here we used three rarity and one threat factor in the NatureServe rank calculator to determine the global conservation rank of P. phreatophila. Known occurrences were compiled, and the online tool GeoCAT (geospatial conservation assessment tool) was used to determine range extent and area of occupancy. Number of occurrences (e.g., populations) was estimated based on the spatial distribution of observations and their proximity to one another. Threat comprised scope, which was assessed in ArcGIS by intersecting the total area covered by a given threat with the known occurrence area of P. phreatophila, and severity, which was estimated based on expert opinion. The resulting conservation rank was G2 (globally imperiled; roughly equivalent to IUCN’s Vulnerable rank); however, complete data were not available for any factor thus motivating the need for further study. When new data are available, the rank can be easily updated with this new information using the rank calculator.
Conservation Status of Native Fishes in the Chihuahuan Desert Region of the United States: a spatial perspective
(Desert Fishes Council, 2021) Perkin, Joshuah; Troia, Matthew; Acre, Matthew
Native fishes in the American Southwest are in need of conservation because of anthropogenic riverscape alterations involving habitat destruction, introduction of non-native species, and dewatering. Status assessments are useful conservation planning tools, but there is a need for transparent, repeatable, and empirically-driven assessment frameworks. We present a multi-criteria status assessment framework based on publicly available geospatial data and apply this framework to native fishes occupying the United States Chihuahuan Desert region. Criteria included (1) area occupied, (2) dependence on human protected areas, (3) genetic risk from non-native congeners, (4) vulnerability to expected climate change, (5) presence of anthropogenic threats, and (6) regional endemism. Of the 65 species reviewed, four are considered globally extinct, three are considered extirpated from the region, and 10 persist but are rarely encountered. Of the remaining 48 species with recent (i.e., post 1999) records, the current assessment ranked 6 (13%) as in danger of extinction (Endangered), 11 (23%) as on a trajectory towards extinction (Vulnerable), 5 (10%) as Near-Threatened, and 26 (54%) as Least Concern. These percentages broadly matched status ranks developed by multiple conservation entities based on a meta-status metric (i.e., status of statuses) that averaged ranks from multiple, existing assessments. Of the five species listed as Endangered under the federal Endangered Species Act (ESA), three were ranked as Endangered and two were ranked as Vulnerable in the current assessment. The two species listed as Threatened under the ESA were ranked as Vulnerable in the current assessment. Three species listed as Endangered and seven species listed as Vulnerable in the current assessment are not currently listed under the ESA. Range contraction scenarios based on recent region-wide studies of four species revealed that the status scores developed here are sensitive to potential species declines. The data-driven framework developed here supplements those used by agencies at state, federal, and international scales and can be repeated over short time intervals to develop responsive and timely status assessments.

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