Reproductive Guilds Research Articles

Small Fish, Big Problems: Life History, Conservation, and the Future of the Rio Grande Silvery Minnow

The Rio Grande Silvery Minnow Hybognathus amarus is a small‐bodied minnow emblematic of a reproductive guild endemic to rivers of the North American Great Plains. This species has been lost from over 90% of its historical range. The species was federally listed as endangered in 1994 and intensive conservation efforts over the past three decades have averted its extinction in the wild. This article synthesizes the life history of the species, causes of decline and existing threats, and prospects for recovery considering ongoing conservation efforts. Restoring multiple self‐sustaining populations remains questionable given large‐scale, irreversible changes to the Rio Grande basin, though the resiliency of the species and established conservation programs hold at least some potential for advancing recovery beyond simply preventing extinction.

Habitat associations of the Rio Grande Silvery Minnow, an endangered desert river fish, from a retrospective analysis based on a period of high abundance

AbstractObjectiveCharacterizing habitat associations is useful to aid in understanding the habitat requirements of native fishes, particularly those of conservation concern. Our study objective was to characterize mesoscale habitat associations of the only remaining wild population of the Rio Grande Silvery Minnow Hybognathus amarus (a federally endangered desert river fish), and provide comparisons with mesohabitat availability in the middle Rio Grande, New Mexico, from 1994 to 1996.MethodsWe collected fish monthly at two sites (separated by 160 km) near the northern and southern limits of the species' current range, and we recorded depth, velocity, substrate, and mesohabitat type for each habitat surveyed. Mesohabitat availability was recorded across 10 equally spaced and fixed transect lines at both study sites.ResultRio Grande Silvery Minnow most frequently occupied mesohabitats characterized by relatively shallow depths (≤25 cm) and low to near‐zero water velocities (≤15 cm/s). Statistical analyses indicated that mesohabitats occupied by the species were not the most frequently available at the study sites, suggesting a preference for shallow, low‐velocity habitats. Relatively high abundance of Rio Grande Silvery Minnow (n = 10,971), especially compared with post‐2009 abundance, facilitated robust characterization of species‐specific habitat associations.ConclusionComparison of our results with other studies of pelagic broadcast‐spawning leuciscids (pelagophils) endemic to the Great Plains and desert rivers of North America suggested broad overlap in mesohabitat associations among members of this reproductive guild. Our work contributes to a growing body of research aimed at conserving this declining reproductive ecotype of freshwater fishes and suggests that increasing hydraulic diversity through innovative management approaches (e.g., habitat creation, restoration of fluvial processes, and preservation of natural streamflow characteristics) will be crucial for their long‐term recovery and conservation.

Contrasts in riverscape patterns of intraspecific genetic variation in a diverse Neotropical fish community of high conservation value.

Spatial patterns of genetic variation compared across species provide information about the predictability of genetic diversity in natural populations, and areas requiring conservation measures. Due to their remarkable fish diversity, rivers in Neotropical regions are ideal systems to confront theory with observations and would benefit greatly from such approaches given their increasing vulnerability to anthropogenic pressures. We used SNP data from 18 fish species with contrasting life-history traits, co-sampled across 12 sites in the Maroni- a major river system from the Guiana Shield -, to compare patterns of intraspecific genetic variation and identify their underlying drivers. Analyses of covariance revealed a decrease in genetic diversity as distance from the river outlet increased for 5 of the 18 species, illustrating a pattern commonly observed in riverscapes for species with low-to-medium dispersal abilities. However, the mean within-site genetic diversity was lowest in the two easternmost tributaries of the Upper Maroni and around an urbanized location downstream, indicating the need to address the potential influence of local pressures in these areas, such as gold mining or fishing. Finally, the relative influence of isolation by stream distance, isolation by discontinuous river flow, and isolation by spatial heterogeneity in effective size on pairwise genetic differentiation varied across species. Species with similar dispersal and reproductive guilds did not necessarily display shared patterns of population structure. Increasing the knowledge of specific life history traits and ecological requirements of fish species in these remote areas should help further understand factors that influence their current patterns of genetic variation.

Understanding ecological response to physical characteristics in side channels of a large floodplain-river ecosystem

Side channels in large floodplain rivers serve a variety of important ecological roles, particularly in reaches where habitat conditions have been degraded or diminished. We developed hypotheses regarding side channel ecological structure whereby we expected species richness of young-of-year fishes to generally be higher in shallower, more physically heterogeneous side channels with lower velocities, with differences based on reproductive guild. We also hypothesized species richness of adult fishes to be higher in side channels with greater heterogeneity that could support diverse foraging resources and provide refugia during extreme flow conditions. To test these hypotheses, we used a 28-year fish community dataset from the Upper Mississippi and Illinois Rivers. Across six study reaches, we assessed metrics of side channel physical size, heterogeneity, and connectivity that were hypothesized to explain variance of fish community response, while accounting for site-level factors across 52 side channels using multilevel models. We then used these side channel-level characteristics in a K-means cluster analysis to classify 1126 side channels across 32 reaches of the river system. Our results indicated that the relative explanatory contributions of physical metrics varied by response variable, providing varying evidence in support of our hypotheses, and indicating that different forms of heterogeneity matter in different ways. Side channel-level factors were more explanatory of fish community responses in side channels of upstream reaches compared to downstream reaches and percent wet forest was the most explanatory side channel-level factor of fish community responses across all models. Our classification of side channels indicated strong spatial contrasts in the abundance and diversity of side channels across reaches. Scaling up to understand how the diversity and abundance of different types of side channels contributes to landscape-scale ecological functions and processes would be useful for establishing targets for reach-scale physical heterogeneity.

ORIGIN, HABITAT AND ECOLOGICAL CLASSIFICATION OF SOME BONY FISHES AVAILABLE IN KHULNA DIVISION, BANGLADESH

The study identified the origin, habitat and ecological classification of 78 bony fish species belonging to 30 families available in Khulna division. Of the total fish species, 9 were found exotic. Among the collected 78 species, a total of 69 fish species were inhabitants of freshwaters while 4 were found in both fresh and brackish waters and the rest 5 species were found in both brackish and marine waters. The collected fishes belonged to eight trophic guilds; carnivore (43) was the dominant group followed by omnivore (16), insectivore (5), planktivore (5), benthivore (4) and larvivore (1). The fishes also represented eight reproductive guilds; phytolithophil (35) was the most dominant guild followed by phytophil (20), pelagophil (6), psammophil (6), guarder (4), bubble nester (4) and mouth brooder (1). The present study indicates that Khulna Division is very rich in fish biodiversity having diverse forms of trophic and reproduction guilds.

Low‐head dam removal increases functional diversity of stream fish assemblages

AbstractDespite the growing number of dam removals, few have been studied to understand their impacts on stream fish communities. An even smaller proportion of dam removal studies focus on the impacts of low‐head dam removals, although they are the most common type of dam. Instead, the majority of removal studies focus on the impacts of larger dams. In this study, two previously impounded Illinois Rivers were monitored to assess the impacts of low‐head dam removal on the functional assemblage of stream fishes. Study sites were sampled each fall from 2012–2015 (pre‐dam removal) and 2018–2020 (post‐dam removal) in three locations: the tailrace, impoundment, and river channel. Fishes were aggregated into habitat and reproductive guilds, relating community changes to habitat, environmental metrics, and stream quality. Prior to removal, the slackwater guild was the most prevalent habitat guild throughout both rivers, while nest builders and benthic spawners were the most abundant reproductive guilds. During the two years following removal, fish assemblage throughout both rivers shifted to a more evenly distributed representation of habitat and reproductive guilds, while restoration of lotic habitat conditions increased, as surface water temperatures decreased and QHEI, IBI, and dissolved oxygen increased. This shift in environmental metrics and increase in overall stream quality increased, particularly in the formerly impounded reaches, indicate diminished habitat homogeneity, and a shift towards natural habitat diversity. This habitat diversification likely led to the restoration of a range of potential niches, thereby increasing the array of guild types inhabiting these rivers, while simultaneously preventing single‐guild dominance.

Fish larvae-environment networks: co-occurrence patterns, nestedness and robustness of reproductive guilds

Fish larvae-environment networks: co-occurrence patterns, nestedness and robustness of reproductive guilds

Characteristics of the natural flow regime paradigm explain occurrence of imperiled Great Plains fishes

AbstractThe natural flow regime (NFR) paradigm posits that naturally occurring temporal fluctuations in streamflow are necessary for maintaining natural ecological communities. Conservation actions guided by the paradigm have contributed to stream organism conservation on a global scale, yet NFR applications in highly altered Great Plains streams are lacking. We analyzed historical (1980–2017) fish occurrence and flow data from sixteen gage locations across three Great Plains river basins with the goal of relating flow indices calculated for one year prior to each fish collection with the occurrence of fishes belonging to the highly imperiled pelagic‐broadcast spawning (PBS) reproductive guild. We fit random forest models using flow indices, gage identification, and watershed area as predictor variables and PBS fish occurrence as the response variable for all suspected or confirmed PBS fishes in each basin. Results revealed that flow indices from all NFR characteristics were useful for predicting PBS fish occurrence, but the identity of the most important flow indices varied by species and river basin. We also found that gage location was an important predictor variable, indicating flow–ecology relationships are spatially contingent and suggesting the influence of other factors that vary spatially (e.g., river fragmentation and water quality). Partial dependence plots identified thresholds in flow indices such as the timing of maximum flows and fall rate that may be associated with the presence or absence of PBS fishes, and these plots can be used to identify flow index target values to benefit conservation efforts. Time series predictions for likelihood of occurrence at a single gage in the Brazos River basin revealed a positive correlation between likelihood of occurrence and non‐drought years for three of four species present, supporting recent findings that drought suppresses PBS fish populations. This study provides insight into the flow requirements of some of the most imperiled stream fishes in North America and contributes to environmental flow science on a global scale by establishing a robust methodology for delineating flow–ecology relationships.

Fish and flows: Abiotic drivers influence the recruitment response of a freshwater fish community throughout a regulated lotic system of the Murray‐Darling Basin, Australia

Abstract Fish assemblages in dryland rivers have life‐history strategies that have evolved in response to environmental conditions and triggers, particularly water temperatures and flow regimes. The regulation of rivers through the construction of dams, weirs and other water diversion structures has altered natural flow regimes and the associated ecological processes of river systems worldwide. Over a 3‐year period, using standardized fish sampling and daily otolith ageing, the recruitment of eight freshwater fish species was monitored in response to various abiotic drivers, including hydrology and water temperatures, throughout the Macquarie River, a large regulated river system of the Australian Murray‐Darling Basin. A data‐driven statistical classification system is provided that groups species into reproductive guilds, based on their recruitment response to hydrology and water temperature, specifically designed for use in environmental flow management. The eight species were grouped into three distinct reproductive guilds that showed similar recruitment responses to the abiotic drivers. Murray‐Darling rainbowfish, Murray cod, and eel‐tailed catfish were considered as a single guild, characterized by seasonal recruitment during a relatively narrow thermal window under low to moderate stable discharges. The second group included common carp, bony herring, and golden perch, which recruited primarily in association with larger flow events. Un‐specked hardyhead and Australian smelt formed a more differentiated guild, recruiting over a broad range of temperatures and discharges. Limitations associated with using a reproductive guild approach to simplify water management are discussed. This study highlighted important relationships among hydrology, water temperatures, and successful recruitment that can, in turn, be used to inform development of adaptive flow management plans and effective use of environmental water for the conservation management of native fish communities. Important considerations in the design of studies that aim to examine relationships between recruitment and abiotic drivers are also discussed.

Landscape determinants of fish reproductive guilds

Species dependent on freshwaters are declining globally. Understanding natural and anthropogenic environmental drivers affecting community structure and species occurrence is crucial for planning management and conservation actions. The aim of this study was to determine which landscape characteristics constrain reproductive guilds in wadeable streams and to explore the influence of reproductive strategy on fish occurrence. We expected reproductive guilds to differ in their associations with landscape determinants (i.e., the landscape characteristics found to constrain our reproductive guilds). This study was conducted in the Delaware River Basin in North America. We compiled existing stream survey and geospatial data from multiple government agencies and scientific organizations for 552 sites. We used ordination and regression techniques to identify important landscape determinants and their associations with reproductive guilds. We identified 12 variables that explained 20.6% of the total variation in reproductive guild composition. Slope, land cover and disturbance variables drove the position of reproductive guilds in ordination space. All reproductive guilds differed in the set of landscape-scale determinants that were selected during modelling. Best subsets of variables selected in regression models indicate that reproductive guild occurrence is significantly explained by catchment characteristics. These characteristics include measures of slope, land use and land cover, disturbance, and climate. Differences in determinants and relationships with reproductive guilds found in regression models, and gradients identified, indicate the importance of different landscape-scale determinants for specific reproductive guilds. Furthermore, our findings suggest a link between the environmental requirements of reproductive guilds and landscape-scale characteristics.

Current assessment of species composition and biological characteristics of fishes in the transboundary rivers in Turkey

The freshwater fishes of Turkey have been studied for more than 150 yr. However, a nation-wide inventory of freshwater fish occurrences in all transboundary river basins (Euphrates–Tigris, Coruh, Kura–Araks, Maritsa and Orontes) has been neither studied nor published. This work is the first extensive study of the composition and biological characteristics of the freshwater fish fauna of the transboundary rivers in Turkey, with special reference to the native and non-native status of species, and the spatial patterns of species e.g., abundance category, endemism, main threats, movement patterns, habitat guild, feeding guild, and reproductive guild. It is determined that a total of 184 fish species in 25 families (including 15 species which are not native, and 30 species are considered as endemic) live in the transboundary river basins in Turkey. Of the 184 fish species: 19 species are abundant, 57 species decrease, and 101 species are data deficient based on IUCN Red List (International Union for Conservation of Nature and Natural Resources). One of the main threats to freshwater fish occurrences in all transboundary river basins are dams. Most fish species in the area are threatened by dams, water extraction, and habitat degradation.

Relationship of Freshwater Fish Recruitment With Distinct Reproductive Strategies and Flood Attributes: A Long-Term View in the Upper Paraná River Floodplain

The flood pulse is the main driving force for communities’ structure and functioning in river-floodplain systems. High synchrony exists between the hydrological cycle and reproductive cycle events for several fish species. However, species with different reproductive strategies can respond in different ways to the flood regime. Thus, this study intends to evaluate the relationship between the recruitment of different reproductive guilds of freshwater fish and flood attributes (flood duration, maximum annual water level, and delay of flood) from a time series of 20 years in the Upper Parana River floodplain, Brazil. The abundance of four guilds was evaluated: (i) long-distance migratory with external fertilization and without parental care (LMEF); (ii) non-migratory or short-distance migratory with external fertilization and without parental care (NEFW); (iii) non-migratory or short-distance migratory with external fertilization and parental care (NEFP); and (iv) non-migratory or short-distance migratory with internal fertilization and without parental care (NIF). Multiple regression analyses were applied between flood attributes and abundance of young-of-the-year or juveniles for each reproductive guild. This study observed a consistent pattern of long-lasting flooding positively influencing the recruitment of all reproductive guilds, while water level intensity and the time of the onset of flooding also influenced some non-migratory strategies. We can conclude that the conservation of fish populations and the maintenance of ecosystem functions and services associated with them need to be considered in the operating protocols of upstream hydroelectric plants, since they are dependent on the flooding controlled by them.

Integration of taxonomic distinctness indices into the assessment of headwater streams with a high altitude gradient and low species richness along the upper Han River, China

Abstract The multimetric index of biotic integrity (IBI) based on fish assemblages has been widely used to monitor aquatic ecosystem status in headwater streams. However, the application of the IBI has generally been biased by the low number of species and natural altitudinal gradients in these systems. To overcome these limitations, taxonomic distinctness and size-weight-based indices were integrated into our candidate metric pool, and calibration was performed to reduce the effects of the altitudinal gradient on the metrics in our study. Eighty-two sites in six headwater streams along a typical high altitude gradient and with low species richness were sampled. Eighty-three candidate metrics were selected to develop our IBI (IBI-Han) based on the systematic screening method. Six metrics based on taxonomic distinctness, habitat, tolerance guild, reproductive guild and trophic guild were finally retained in the IBI-Han: average taxonomic distinctness, percent rheophilic species, percent tolerant species, percent biomass of water column species, percent lithophilic species, and percent carnivorous species. The IBI-Han performed well in discriminating anthropogenic disturbances not only at training sites but also at testing sites, which suggests that our method could provide a reliable evaluation of the condition of headwater stream ecosystems. Among the six rivers, the Jinshui River showed relatively healthy ecosystem status, while the other five streams were disturbed by various human activities. Our work highlights that taxonomic distinctness indices are robust biomonitoring indices that can be combined with other functional indices to assess high altitude gradient streams in the upper Han River. We believe that the process of developing the IBI-Han could be regarded as a reference for managing headwater streams in other regions of China or in other states.

Trends in Distribution of Plains Minnow (Hybognathus placitus) in Kansas from 1964 to 2017

Streams of North America have been degraded by over a century of anthropogenic stressors, including channelization, fragmentation, impoundment, dewatering, and the modification of the natural flow regime. These stressors have contributed to the decline of many freshwater fish species and are particularly detrimental to the pelagic-broadcast spawning reproductive guild of cyprinids. Members of this guild require an unfragmented river section of 458 (±137) river kilometers (rkm) in length to persist. The Plains Minnow is a member of this reproductive guild and is listed within Kansas as a threatened species. Plains Minnow were once common throughout Kansas, but have experienced declines in abundance and distribution. Using historical data and 14 y of new data, we analyzed the proportion of sites occupied by Plains Minnow over time within Kansas as a whole and within specific river basins using parametric linear regression models and nonparametric localized regression models. We found Plains Minnow to be declining within the historical range of the species across the state as a whole and specifically within the Smoky Hill-Saline and Lower Arkansas river basins. We found Plains Minnow distributions to be unchanging within the Kansas-Lower Republican and the Cimarron river basins. Within the Smoky Hill-Saline and the Kansas-Lower Republican river basins, the proportion of sites occupied by Plains Minnow has been at or near zero for the majority of the time period studied. Our findings support previously published studies and contribute to the growing body of evidence that Plains Minnow continue to decline within Kansas. If the species is to recover within the state, anthropogenic stressors will have to be mitigated, and repatriation efforts will need to be conducted.

Embryonic development of the bullseye puffer Sphoeroides annulatus (Tetraodontidae): A morphofunctional approach to ontogenetic steps.

The embryonic development of the bullseye puffer, Sphoeroides annulatus, was characterized on the basis of the theory of saltatory ontogeny. This theory predicts a correlative relationship between the ontogeny-type in an altricial-precocial spectrum and the habitat that a species occupies within an unstable-stable environmental spectrum. Because S. annulatus inhabits a variety of unstable environments along a wide latitudinal range, the hypothesis that this species presents one of the most altricial embryonic developments among tetraodontids was tested. Based on major developmental events that marked the ontogenetic thresholds nine embryonic steps were identified. Developmental features such as small adhesives eggs, lack of vitelline circulation, small free embryos swimming up at hatching guided by positive phototaxis, and small first-feeding larvae actively swam in the water column, suggest that S. annulatus belongs to the reproductive guild of the nonguarders-lithopelagophils. Moreover, a comparative analysis of the developmental sequences, egg size, and first-feeding larvae size between tetraodontids confirms the hypothesis of this study and supports the evolutionary principle of the altricial-precocial spectrum postulated in the theory of saltatory ontogeny.

Oil globule size in fish eggs: A matter of biome and reproductive strategy

AbstractHere, on the basis of published information upon over 800 species from 39 orders and 202 families, we analyse how the size of oil globules in fish eggs varies between reproductive guilds and environments with contrasting salinities. About 80% of marine fishes produce eggs with oil globules, the volume of which (VO) never exceeds 9% of the egg reserves and averages 2%. These proportions vary very little between marine fish species producing pelagic or demersal eggs. Fewer freshwater fishes (about 40%) produce eggs with oil globules, but their globules are much larger (mean VO of 10%) and their volumes vary considerably between reproductive guilds: VO is on average 3–10 times lower in freshwater species with demersal eggs than among freshwater pelagophils and aphrophils (i.e., bubble nesters), where it averages about 40% (range of 23%–69%) of the egg reserves. These results support the idea that oil globules serve to hydrostatic lift in fresh waters, but not or very little in marine waters, where egg buoyancy can be achieved at a lower energy cost through egg hydration. Advantages and constraints of oil globules in fish eggs are discussed in the light of species producing eggs with very large oil globules (VO > 20%): access to oxygen‐rich water layers that are indispensable for egg development vs. smaller size of larvae at first feeding, since the saturated lipids contained in oil globules essentially serve very little to tissue construction.

Mass Upstream Dispersal of Pelagic-Broadcast Spawning Cyprinids in the Rio Grande and Pecos River, New Mexico

Pelagic-broadcast spawning minnows are a reproductive guild of fishes, of which several species occur in the American Great Plains and Southwest. The eggs and larvae of these species drift laterally and downstream, with drift distances varying depending on channel conditions and flow. Persistence or recolonization of these species in upstream reaches must depend on retention of eggs and larvae or upstream dispersal of later life stages, otherwise net downstream displacement of eggs and larvae would result in upstream extirpations. However, only a few individuals of several species have been observed dispersing. Here, we describe 2 direct visual observations of the young-of-year of 4 species of pelagic-broadcast spawning minnows dispersing upstream en masse. In August 2009, we observed Plains Minnow (Hybognathus placitus), Speckled Chub (Macrhybopsis aestivalis), and Rio Grande Shiner (Notropis jemezanus) dispersing upstream. The continuous shoal of fish was >200 m in length and was dispersing upstream at a rate of >1000 fish/min. In July 2017, we observed a continuous shoal of Rio Grande Silvery Minnow (Hybognathus amarus) approximately 1.9 km in length dispersing upstream at a rate between 350 and 1500 fish/min. While such dispersal events are rarely observed, they may be important for maintenance of populations in upstream areas.

Fish beta diversity responses to environmental heterogeneity and flood pulses are different according to reproductive guild

ABSTRACT In floodplain communities, beta diversity is influenced by different factors; however, environmental heterogeneity and floods are believed to be particularly influential. The influence of environmental heterogeneity and floods on beta diversity may vary among guilds that present different ecological traits. This study evaluated the correlation between the environmental heterogeneity and flood periods and the beta diversity of trophic and reproductive guilds of fish assemblages. Sampling was conducted quarterly between 2000 and 2012 in the upper Paraná River floodplain. The environmental heterogeneity and period (i.e., dry or flood) were associated with the beta diversity of each guild based on the results of generalized least squares linear models. Only guilds with parental care were influenced by the interaction between environmental heterogeneity and period. The beta diversity of the other guilds presented no relationship between environmental heterogeneity and period. It is likely that species with parental care presented less dispersal capacity, which increased the dissimilarity among assemblages. The higher dispersion rates of the other guilds may be responsible for the lack of relationship between the beta diversity and the environmental heterogeneity and period. In sum, these results suggest that reproductive guilds influence how environmental heterogeneity and floods affect beta diversity variation.

Importance of dam-free stretches for fish reproduction: the last remnant in the Upper Paraná River

Abstract Aim: This study uses the abundance of fish eggs and larvae to evaluate the importance of the main channel of the Paraná River and the adjacent areas of the floodplain, in the last dam-free stretch in the Brazilian territory, for the spawning and development of fish of different reproductive guilds, in order to obtain subsidies to assist in the management and conservation policies of this area, focusing on the maintenance of dam-free areas. Methods Data were taken quarterly from August 2013 to May 2015, in 25 sites, grouped into three biotopes: main channel, tributaries and lagoons. Possible spatial variations in fish spawning and development as well as composition and structure of larvae were evaluated. Results Higher densities of eggs were found in tributaries (Paracaí and Amambai rivers) and greater densities of larvae were observed in lagoons (Saraiva). Significant differences in composition and structure of larvae were detected only between sampling stations. As for taxonomic composition, 29 taxa were recorded, mostly non-migratory. However, long-distance migratory were also widely distributed, such as Brycon orbignyanus, Pseudoplatystoma corruscans, Prochilodus lineatus, Piaractus mesopotamicus and Rhaphiodon vulpinus, as well as invasive species Platanichthys platana and Hemiodus orthonops. In turn, Salminus brasiliensis presented low occurrence. Conclusions This study evidenced that different species spawn in the region, mainly in tributaries, and their eggs and larvae are transported to the main channel of the Paraná River and adjacent lagoons, to complete their early development. The capture of larvae of important migratory species suggests that this environment still exhibits suitable conditions for their reproduction, mainly due to the presence of dam-free tributaries. Also, they emphasize the importance of the integrity of these environments for the maintenance of the regional fish fauna, and it is extremely important the monitoring of reproduction of the most endangered species, as well as of invasive species.

The emblematic minnows of the North American Great Plains: A synthesis of threats and conservation opportunities

AbstractAnthropogenic changes to the Great Plains rivers of North America have had a large, negative effect on a reproductive guild of pelagic‐broadcast spawning (PBS) cyprinid fishes. The group is phylogenetically diverse, with multiple origins of thePBSmode. However, because of incomplete life‐history information,PBSdesignation often relies only on habitat and egg characteristics. We identified 17 known or candidatePBSfishes and systematically synthesized the literature on their biology and ecology in relation to major threats to persistence. Research output on an individual species was unrelated to conservation status, but positively correlated with breadth of distribution. ThePBSspecies have opportunistic life‐history strategies and are typically short‐lived (generally 1–3 years) fishes. ManyPBSspecies have truncated ranges showing declines in both distribution and abundance, especially those endemic to the Rio Grande catchment. Fundamental habitat associations are unknown for many species, particularly regarding seasonal shifts and early life stages. Critical thermal tolerances have been quantified for fivePBSspecies and are generally >35°C. Turbidity and salinity changes are linked to responses at multiple life stages, but information is lacking on interactions between water quality and quantity. Hydrologic alteration appears to be a primary threat toPBSspecies, through complex interactions with landscape fragmentation, and habitat change. We highlight areas where scientific and management communities are lacking information and underline areas of potential conservation gain.