ArticlePDF Available

Conservation Status of Imperiled North American Freshwater and Diadromous Fishes

Authors:

Abstract and Figures

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.
Content may be subject to copyright.
A preview of the PDF is not available
... Between 1900 and2010, 40 North American freshwater fish species have gone extinct (Shirey et al., 2018). It is estimated that 39 % of North American freshwater fish species are currently imperiled, and the number of imperiled freshwater fish has increased by 92 % since 1989 (Jelks et al., 2008). Many factors contribute to the increased risks of extirpation or extinction of freshwater fish species, including habitat destruction, introduced species, pollution, hybridization with non-native species, and overexploitation. ...
... They were first described in 1999 (Williams and Burgess, 1999). They are listed as vulnerable on the American Fisheries Society list of imperiled freshwater fishes of North America (Jelks et al., 2008). Within their native range, shoal bass have been negatively impacted by dams and non-native species in large portions of their native range (Taylor et al., 2018a). ...
Article
Freshwater fishes are among the most biodiverse vertebrate groups and among the most threatened by anthropogenic activities. Many occur in small and geographically restricted populations that are increasingly subject to catastrophic events (hurricanes, wildfires, extreme floods and droughts), but it has rarely been possible to assess the impacts of such events. Here we document the decline and recovery of a regularly monitored, small shoal bass (Micropterus cataractae) population in the Chipola River, Florida following a catastrophic hurricane disturbance. The Chipola River population has the lowest level of interspecific hybridization (over 90 % nonintrogressed shoal bass) within the species’ range, a census population size of 2165 (95 % CI [1,383, 3,801]) in 2009 and a genetically effective population size Ne of 135 (95 % CI [70, 472]). In 2018, Hurricane Michael devastated the Chipola River and watershed. A survey conducted in 2019 indicated a severe decline (91 %) in relative population abundance and a very low Ne at 21 (95 % CI [16, 29]). However, the detection of young-ofyear fish indicated that the depleted population had experienced successful reproduction. In fall 2021, the census population had recovered to 1039 fish (95 % CI [660, 1,814]) and Ne at 40 (95 % CI [31, 50]). While the population has shown considerable resilience in the face of hurricane disturbance, it remains vulnerable to future catastrophic events and may also suffer a long-term reduction in its adaptive potential due to a relatively low effective population size. To address these threats, continued monitoring is necessitated and targeted measures such as translocation of non-introgressed individuals from neighboring populations or establishment of a captive population of sufficient effective population size may be required to conserve the species in the long term.
... The distribution and habitat of the Spring Cavefish almost mirrors that of the Barrens Topminnow (Fundulus julisia) a critically endangered species restricted to springs and spring-fed creeks (Williams and Etnier 1982;Jelks et al. 2008), yet the genetic signature of the two species is very different. The topminnow has two ESUs between the Elk River and Caney Fork, and 2 MUs between two different river systems within the Caney Fork drainage (Hurt et al. 2017). ...
Article
Full-text available
The North American freshwater genus Forbesichthys is composed of facultative cave-dwelling fishes restricted to springs and caves in southern Illinois, southeastern Missouri, southwestern Kentucky, and central Tennessee. These fishes were previously considered a single species, the Spring Cavefish (F. agassizii), but recent molecular evidence led to the recognition of the Shawnee Hills Cavefish (F. papilliferus). The Shawnee Hills Cavefish is hypothesized to be restricted to Illinois, Missouri, Kentucky and north-central Tennessee, whereas the Spring Cavefish is restricted to the Eastern Highland Rim of central Tennessee. However, the distributions of Forbesichthys are difficult to ascertain due to their intermittent appearance in surface springs, making sampling challenging. We assessed the species status, distribution, connectivity, and population sizes of the Forbesichthys spp. using Restriction-site Associated DNA sequencing (RADseq) and the mitochondrial NADH dehydrogenase 2 locus. Our results corroborate the recognition and hypothesized distributions of the Shawnee Hills Cavefish and Spring Cavefish. Furthermore, we suggest the recognition of three Evolutionary Significant Units (ESUs) and two Management Units (MUs) within the Shawnee Hills Cavefish. Although all populations analyzed appear to have reasonable genetic diversity and population stability over time, this regionalization has implications for both groundwater policy and management. Our study provides important information relevant to understanding potential population distributions and the identification of unique lineages that may deserve additional protection.
... Many riverscapes are fragmented by dams and water diversions that modify natural flow regimes, degrade habitats, and contribute to the imperilment of native freshwater fishes. Dam construction and water extraction have compromised habitat quality, riverine connectivity, and restricted fish movement [1], contributing to widespread range reductions and local population declines [2,3]. Fragmentation exacerbates the effects of environmental disturbance, such as drought, and in extreme cases can lead to recruitment failure, prevention of recolonization from downstream populations, and ultimately extirpation [4,5]. ...
Article
Full-text available
Background Unfettered movement among habitats is crucial for fish to access patchily distributed resources and complete their life cycle, but many riverscapes in the American Southwest are fragmented by dams and dewatering. The endangered Rio Grande silvery minnow (Hybognathus amarus, RGSM) persists in a fragmented remnant of its former range (ca. 5%), and its movement ecology is understudied. Methods We tracked movements of hatchery-reared RGSM, tagged with passive integrated transponder tags, using stationary and mobile antennas from 2019 to 2022. We quantified probability of movement and total distance moved by RGSM released above and below a dam. We then assessed how well two prevailing riverine movement theories (i.e., restricted movement paradigm [RMP] and colonization cycle hypothesis [CCH]) explained RGSM movement patterns. Results We detected 36.8% of released RGSM (n = 37,215) making at least one movement. Movements were leptokurtic and substantially greater than expected based on the RMP for both stationary (1.7–5.9 m) and mobile (30.3–77.8 m) individuals. On average, RGSM were detected at large for 75 days and moved a total of 12.2 rkm within a year. The maximum total distance moved by RGSM was 103 rkm. Similarly, we observed a multimodal distribution of detected range sizes with a mean detected range of 2.4 rkm and a maximum detected range of 78.2 rkm. We found little support for an upstream movement bias, as expected under the CCH, and most movements (74%) were directed downstream. Conclusions Our data suggest RGSM are highly mobile, with the ability to make long-distance movements. Neither movement theory adequately described movement patterns of RGSM; instead, our findings support a nomadic movement pattern and an apparent drift paradox matching recent studies of other pelagic-broadcast spawning minnows where populations persist upstream despite experiencing downstream drift as larvae. Resolution of the drift paradox may be achieved through further, targeted studies into different aspects of the species’ life history. Quantification of RGSM movement provides crucial insights into the species’ movement ecology and may help define the appropriate scale of recovery efforts.
... We fit a linear model with fragment length as the dependent variable and mobile component movement rate as the independent variable using the 'lm' function from the 'stats' package in R. We then calculated the conservation "meta-status" (i.e., status of statuses) for each PBS species included in the study based on the methods of Perkin et al. (2021). Meta-status was based on conservation listings by the International Union for the Conservation of Nature (IUCN Red List; IUCN, 2022), NatureServe (2023), American Fisheries Society (AFS; Jelks et al., 2008), and the U.S. Fish and Wildlife Service (USFWS, 2023). Because each entity uses slightly different nomenclature for conservation status, we ranked listings such that the lowest rank was most imperiled, including 1 (Endangered or G1), 2 (Vulnerable, Threatened, or G2), 3 (Near-Threatened, G3), and 4 (Not Listed, Least Concern, G4, or G5). ...
Article
Full-text available
Fish diversity, an important indicator of aquatic ecosystem health, is declining due to water pollution, overfishing, climate change, and invasive species. Effective surveying and monitoring are required to protect fish diversity. Here, a high-sensitivity environmental DNA (eDNA) metabarcoding technique was used to investigate fish diversity in the Danjiang River, Shaanxi Province, China. In total, 59 species were identified in eight orders, 19 families, and 40 genera. Cypriniformes and Perciformes were the main groups in the survey area, while Cyprinidae accounted for 50.85% of the total fish species. Rhinogobius similis (19%), Hemibarbus umbrifer (11%), Gnathopogon herzensteini (10%), Triplophysa stewarti (8%), and Zacco platypus (7%) were the dominant species. Eight rare and two exotic fish species were identified. Combined with analysis of historical data, the richness of fish identified using eDNA metabarcoding was significantly higher than that of fish captured in ground cages. Temperature, pH, and oxidation-reduction potential are the main environmental factors that affect the spatial distribution of fish communities. These results suggest that eDNA metabarcoding could be a new tool with broad application prospects; however, local databases must be improved. This study provides theoretical data and a methodological reference for protecting and managing fish diversity in the Qinling Mountains. Supplementary Information The online version contains supplementary material available at 10.1038/s41598-024-80907-z.
Article
Full-text available
The presence of cryptic species can hinder effective conservation planning and implementation, as has been the case for speciose groups of freshwater fishes that are difficult to differentiate due to conserved morphologies. The West Texas shiner Notropis megalops and the Texas shiner Notropis amabilis are a cryptic pair of leuciscids (minnows) that co‐occur in spring‐fed tributaries of the Rio Grande in Texas and Mexico. Both N. megalops and N. amabilis are listed as Species of Greatest Conservation Need by the Texas Parks and Wildlife Department. Notropis amabilis is widespread and listed as apparently secure by Texas Parks and Wildlife Department whereas N. megalops has a very limited distribution and has not been ranked by Texas Parks and Wildlife Department because of data deficiency. Morphological differences between these species have been described; however, proper identification in situ remains problematic. Furthermore, given their range of overlap there is potential for hybridization, and limited genetic data have been collected comparing the species. Therefore, reduced representation genomic and mitochondrial sequencing data were used to reassess the distinctness of the species, screen for hybridization, and characterize their relative frequencies throughout their range of overlap. Genomic analyses recovered two distinct genetic groups corresponding to the species (F'CT = 0.89) with no evidence of admixture or introgression. The species were found to co‐occur at three sampling locations, two in the Devils River and one in the Pecos, but not in equal frequencies. Overall, these results provide data and tools for further research on N. megalops needed for accurate conservation policies and management practices.
Thesis
The Blue Sucker, Cycleptus elongatus, occurs in large rivers primarily in the Mississippi River basin. Their imperiled status has called attention to the need for its management and protection. Estimating age is crucial for directing management, but past studies have varied in their choice of hard structure, resulting in uncertainty regarding the basic life history of this species. Because the Wabash River Blue Sucker population may be one of few surveyable populations with high abundance and successful reproduction, their demographics can provide a benchmark against which threatened populations can be compared. We harvested Blue Suckers (n= 168) from the lower Wabash River and compared age estimations from multiple hard structures. Otoliths yielded more precise and credible age estimates than other structures. Otoliths assigned ages up to 42 years. Annual mortality was 4.5%, and growth was modeled as TL= 680.29038∙(1-e (-0.15898∙ Age+ 5.14037)), where TL= total length (mm) and Age= otolith age (years). Fecundity averaged 110,933 eggs/female. The population length-weight regression was Log 10 (WT)= 3.323∙ Log 10 (TL)-5.9592 where WT= weight (g) and TL= total length (mm). Average relative weights followed a declining trend from 2008 to 2019, and this trend was mirrored in the declining average conditions of four other benthic invertivorous fishes in the Wabash River. We suggest that Blue Suckers can serve as bioindicators for the Wabash River ecosystem and their declining relative weights should be regarded as early symptoms of community level change.
Article
Full-text available
This study describes the process of Pomacea patula catemacensis grow-out in outdoor tanks. Experimental juvenile snails (1.5-2 months old) obtained from wild breeding snails were reared using a recirculating aquaculture system (RAS). The present study focused on increasing the surface area of growth tanks to be used by snails without affecting their growth and survival by adding shelters throughout the water column, which also worked to harbor snails. Two treatments were tested; T1: shelters made with curved clay tiles, T2: curved PVC shelters, and control (without shelters) in triplicate. The stocking density was set at 420 ind m-2 in tanks with 1 m3 total volume, and the culture period was 150 days. The final weight of the snails was significantly higher in control and PVC shelter groups (9.14 ± 2.2 and 8.83 ± 2.31 g, respectively), with PVC shelters showing the highest productivity in total biomass (12.03 ± 0.86 kg tank-1, P < 0.05). Final survival (%) was not significantly different among treatments (56.49 ± 1.62 to 58.05 ± 0.62).
Article
Full-text available
Identification of taxonomically cryptic species is essential for the effective conservation of biodiversity. Freshwater‐limited organisms tend to be genetically isolated by drainage boundaries, and thus may be expected to show substantial cryptic phylogenetic and taxonomic diversity. By comparison, populations of diadromous taxa, that migrate between freshwater and marine environments, are expected to show less genetic differentiation. Here we test for cryptic diversity in Australasian populations (both diadromous and non‐diadromous) of two widespread Southern Hemisphere fish species, Galaxias brevipinnis and Galaxias maculatus. Both mtDNA and nuclear markers reveal putative cryptic species within these taxa. The substantial diversity detected within G. brevipinnis may be explained by its strong climbing ability which allows it to form isolated inland populations. In island populations, G. brevipinnis similarly show deeper genetic divergence than those of G. maculatus, which may be explained by the greater abundance of G. maculatus larvae in the sea allowing more ongoing dispersal. Our study highlights that even widespread, ‘high‐dispersal’ species can harbour substantial cryptic diversity and therefore warrant increased taxonomic and conservation attention.
Chapter
Full-text available
In the five years since we first reviewed the status of the world’s fishes (Moyle and Leidy 1992), there has been an explosion of new information on the conservation of aquatic organisms and their ecosystems. Notwithstanding this surge of interest, many aquatic ecosystems remain poorly understood because conservation biology remains primarily focused on the loss of biotic diversity in terrestrial environments. Loss of diversity in aquatic environments has received comparatively little attention, even though the physical, chemical, and biological degradation of aquatic environments is widely recognized as a major problem, usually in the context of the spread of human disease, loss of fisheries, or degraded water quality for drinking, irrigation, or recreation. Yet aquatic habitats support an extraordinary array of species, many of which are being lost as their habitats deteriorate.
Article
Full-text available
Human activities, particularly habitat destruction and species introductions, are resulting in increased homogenization of once unique biogeographic regions. In the southeastern United States, extensive endemism occurs among highland fish species that have specialized ecologies, are adapted to cool, clear, nutrient-poor conditions, and are sediment-intolerant. Highland streams flow into lower elevation systems, which are often inhabited by more widespread, generalist fish species adapted to warmer, more turbid, fine-sediment-rich, and nutrient-rich conditions. Common land use practices, such as deforestation, degrade stream habitats and reduce habitat diversity, which is often correlated with taxonomic and ecological diversity. Habitat homogenization can thus cause assemblage homogenization via loss of native species and addition of nonindigenous species. However, midpoints in the homogenization process may be characterized by constant or even increased species diversity because generalist, sediment-tolerant, “native” species invade from downstream areas. Perusal of a species list for a river system would not reveal such invasions because lists seldom discriminate between upstream and downstream assemblages in a drainage. Traditional metrics often used in biological assessment, such as species richness (α diversity) and evenness, should not include invasive species, whether native or exotic. Greater attention should be paid to the actual species present and their ecological requirements, and to changes in overlap in species occurrence among regions. Aquatic ecosystem integrity can degrade despite apparent increases in species diversity.
Article
Full-text available
Faunal homogenization and differentiation occur when geographic regions show increased or decreased, re- spectively, similarity to each other in species composition owing to introductions and extinctions or extirpations. I used species presence-absence data for "native" (i.e., estimated species compositions before European settlement) and "total" (i.e., including nonnative fishes and extinctions) faunas to examine faunal similarity of freshwater fishes among aquatic ecoregions of British Columbia and among Canadian provinces and territories. British Columbia ecoregions showed faunal differentiation as the mean Jaccard's faunal similarity coefficient for total faunas was significantly less than that for native faunas (31.4% versus 34.9%), but some ecoregions showed homogenization (e.g., Vancouver Island and Columbia River ecoregions). Comparisons across Canada showed low but significant homogenization; average pairwise Jaccard's coefficient was higher in total versus native faunas (29.1% similarity versus 27.8%, respectively). British Columbia's fish fauna increased the most in similarity to other areas (except the three territories), with an average increase of 4.9%. Native faunal similarity patterns are part of Canada's natural heritage but are threatened by human- mediated increases in nonnative species and extinctions. This analysis provides a baseline to track changes in inter- regional faunal relationships at different geographic scales. Résumé : L'homogénéisation et la différentiation de la faune se produisent lorsque des régions géographiques présen- tent des compositions spécifiques respectivement plus semblables ou moins similaires à cause d'introductions ou
Article
Recent essays on the species problem have emphasized the commonality that many species concepts have with basic evolutionary theory. Although true, such consensus fails to address the nature of the ambiguity that is associated with species-related research. We argue that biologists who endure the species problem can benefit from a synthesis in which individual taxonomic species are used as hypotheses of evolutionary entities. We discuss two sources of species uncertainty: one that is a semantic confusion, and a second that is caused by the inherent uncertainty of evolutionary entities. The former can be dispelled with careful communication, whereas the latter is a conventional scientific uncertainty that can only be mitigated by research. This scientific uncertainty cannot be `solved' or stamped out, but neither need it be ignored or feared.
Article
Little is known about the population status of the parasitic lamprey Lampetra spadicea and its nonparasitic counterpart L. geminis, relict species endemic to the highlands of central Mexico. We used literature and museum specimen data to delineate the historical distribution of both species and then conducted field surveys to determine current distribution and abundance. Lampetra spadicea was historically found in Lago de Chapala; the lower reaches of the Rio Zula, which enters the Rio Grande de Santiago just below the outlet of Lago de Chapala; the Rio Duero, which enters the Rio Lerma about 20 km above the inlet to Lago de Chapala; and endorheic Lago de Cuitzeo and its tributary Rio Grande de Morelia drainage, which are adjacent to the Rio Lerma drainage. Lampetra spadicea apparently has been eliminated from the Morelia-Cuitzeo basin and persists, in low numbers, at only a few localities in the Lerma-Chapala-Santiago basin. It should be considered endangered. Declines in distribution and abundance were probably caused by environmental degradation. Lampetra geminis was historically known from the upper Rio Duero and Rio Grande de Morelia drainages, and it remains locally common in both. However, the range of the species is small, and pollution and habitat modification threaten several populations. This species should be given ''special concern'' status.
Book
Refecting what a new generation of conservation biologists is doing and thinking, this vital and far ranging second edition explores where conservation biology is heading. It challenges many conventions of conservation biology by exposing certain weaknesses of widely accepted principles. Combining contributions from both the school and the new breed of conservation biologists, this insightful text focuses primarily on topics the are integral to the daily activities of conservation biologists. Several chapters address ecosystem restoration and biotic invasions as well as the the mechanics of population viability analyses, which are now a routine facet of conservation efforts. A case history approach is implemented throughout the book, with the use of practical real-world examples. Furthermore, an in-depth look at quantitative analyses is presented, allowing for models and mathematical analyses to pinpoint limitations in existing data and guide research toward those aspects of biology that are most likely to be critical to the dynamics of a species or an ecosystem.