Nongame Fish Research Articles

For the love of suckers: scientific benefits of engaging volunteers to monitor migrations and advocate for native non-game fishes

For the love of suckers: scientific benefits of engaging volunteers to monitor migrations and advocate for native non-game fishes

Live‐bait industry as a pathway for movement of nonnative and invasive species: Implications for conservation of native Texas fishes

AbstractObjectiveLive‐bait species are widely used in recreational fishing throughout the United States. However, the use of invasive fish species as live bait has been identified as a common pathway for their introduction into aquatic ecosystems. We assessed the role that the live‐bait industry has in facilitating the introduction of nonnative and invasive species into Texas rivers. We focused on two invasive cyprinodontid species, the Sheepshead Minnow Cyprinodon variegatus and Gulf Killifish Fundulus grandis, which are believed to have been introduced into inland Texas rivers via bait‐bucket releases by anglers.MethodsWe conducted telephone and in‐person surveys of live‐bait shops in Texas on a seasonal basis (summer, fall, winter, spring) for 1 year. Locally owned bait shops and regional aquaculture facilities and hatcheries were included in the surveys.ResultSurveys did not reveal the presence of these invasive cyprinodontids in inland bait shops but did reveal the sale of nonnative Goldfish Carassius auratus and their black color morph, the black salty goldfish. Surveys conducted among inland and coastal live bait shops confirmed the sale of only one nonnative bait fish and six bait items native only to certain regions of Texas. Telephone surveys with aquaculture industry experts revealed that the aquaculture industry was also facilitating the movement of nonnative game and nongame fish species throughout the state.ConclusionGiven the potential for nonnative and invasive species to negatively affect recipient aquatic ecosystems, the continued distribution of such species within the aquaculture industry represents a potential threat in Texas. Our findings highlight the need for close monitoring of the live‐bait industry in the state to prevent further introductions into inland waters and reduce potential ecological risks to native fish populations and overall ecosystem functions and services.

Bowfishing shoot and release: High short‐term mortality of nongame fishes and its management implications

AbstractObjectiveAlthough bowfishing is legal in all 50 states in the USA, the practice of releasing shot fish is only legal in 8 states. An argument favoring this practice has been that survival of fish after shoot‐and‐release fishing is high. Bowfishing mortality trials were conducted in 2021–2022 in Lake Texoma, Oklahoma, to quantify shoot‐and‐release mortality and characterize the mortality via the location of the wound associated with the release of fish shot by bowfishing.MethodsA total of 240 nongame fish were shot by experienced bowfishers with conventional bowfishing equipment and held in convalescent pools, with control fish captured by electrofishing to document short‐term mortality up to 5 days.ResultOverall mortality of bowfished fish was 87% versus 0% for control fish. Fish shot in critical areas (head, internal organs, or spine; 78% of total) suffered 96% mortality, whereas fish shot in noncritical areas (dorsal musculature, tail, or fins) experienced 52% mortality. In addition, 13.7% of fish shot were not successfully retrieved. Shot fish were generally older (mean = 19.4 years, range = 3–54) and contained more females (62%) than control fish (mean = 12.5 years, range = 2–39; 37% female), providing evidence that bowfishing can remove individuals of great recruitment value. The shoot‐and‐release mortality rates in this study, for fish shot in both critical and noncritical areas, exceeded mortality from a wide range of angler catch and release in other studies.ConclusionThe high mortality rate associated with shoot and release observed in this study and as practiced by recreational bowfisheries renders shoot and release inconsistent with scientifically regulated and sustainable bowfisheries for native nongame species. These results provide evidence that the bow and arrow, when aimed at animals, is a weapon that is intended to kill. Bowfishing should realistically be managed as a 100% consumptive (i.e., kill) pursuit in which shoot and release is prohibited and nonretrieval of shot fish is accounted for.

Validation and Comparison of Age Estimates for Smallmouth Buffalo in Oklahoma Based on Otoliths, Pectoral Fin Rays, and Opercula

AbstractWith an increased interest in nongame fishes such as buffalofishes (Catostomidae, Ictiobus), there is a need for better foundational data on their life history. Bigmouth Buffalo I. cyprinellus, for example, have been found to live for more than a century. Age estimates for other sucker species have similarly suggested long life spans, but validation studies as reference points are often lacking. We conducted a 3‐year study on Smallmouth Buffalo I. bubalus in Oklahoma to validate annual increments on three hard part structures (otoliths [lapilli], pectoral fin rays, and opercula) typically used for age estimation. We marked wild fish with oxytetracycline (OTC) injection and stocked those fish into a hatchery pond to create a population of fish with known times since marking. Furthermore, reproduction in the pond allowed us to validate annulus formation in young fish. We analyzed 117 fish and found that otoliths were more reliable, precise, and accurate than the other two structures for detecting OTC marks and counting annuli. Age estimates, from 1 to 61 years, were greatest when otoliths were used, with 99% of estimates corresponding to known time since marking or known age. Otoliths appear to be the only reliable structure for accurately estimating the age of Smallmouth Buffalo within 1 year of actual age, and their use indicates that this species can live for more than six decades in Oklahoma.

Bycatch in a Coastal Black Drum Trotline Fishery

AbstractBycatch remains a challenging issue for many fisheries across the globe. Due to the cost and effort of (bycatch) observer programs, many fisheries—particularly those not in U.S. federal waters—operate with little information about bycatch. The Black Drum Pogonias cromis and Sheepshead Archosargus probatocephalus fishery in Louisiana comprises one of the largest fisheries by volume and in recent years has exceeded US$5 million in annual value. The vast majority of Black Drum and Sheepshead are harvested by the baited trotline fishery that operates in state waters. Very little is known about the bycatch from this fishery; however, because of the magnitude of the fishery quantifying bycatch is needed for the management of this resource. We observed 59 baited trotline sets on 13 different dates spanning 2 years of sampling (2020–2021). The total bycatch (n = 1,392) was similar in number to the harvest of the target species (n = 1,265). However, most bycatch species were nongame fishes and were released alive. Of all the bycatch caught, only 4% was dead and the majority of that 4% (47 out of 57 fish) consisted of Gafftopsail Catfish Bagre marinus and Hardhead Catfish Ariopsis felis, both species for which there is little fishery and no known issues with the populations. We also found that catch rates for bycatch did not vary by season or between the two areas fished. The catch rate of bycatch did not increase as the catch rate of target species increased; although, as expected, bycatch mortality did significantly increase as water temperature increased. Overall, the baited trotline fishery for Black Drum and Sheepshead catches about one individual of bycatch for one target individual; however, the overall extremely low bycatch mortality (of common species) suggests that this fishery operates with few adverse effects on nontarget species.

Salmon of the Southeastern U.S.: Sucker migrations deliver resource subsidies to oligotrophic stream

AbstractThe ability for migratory fishes to move commonly limiting resources such as nitrogen (N) and phosphorus (P) between discrete environments can have pronounced effects on recipient ecosystems. To further understand the geographic and taxonomic scope of migratory fish resource subsidies, we quantified N and P subsidies delivered by adfluvial suckers (Smallmouth Buffalo, Ictiobus bubalus) via excretion, eggs and carcasses to a small oligotrophic stream during their annual spawning migration. We also compared nutrient inputs from migrant buffalo with watershed nutrient export to assess the likelihood that delivered nutrients were ecologically important. We estimated that approximately 67,000 buffalo delivered 730 kg of N and 80 kg of P to Citico Creek as a result of excretion and egg subsidies across three migration waves. We estimated that carcasses delivered negligible amounts of N and P due to extremely low retention. The ratio of migrant inputs (Mw) to system export (Ew; Mw/Ew) varied amongst three migration waves and compounds (i.e. dissolved inorganic nitrogen, ammonium and soluble reactive phosphorus), with values for Mw/Ew ranging from 0.25 to 5.10, reflecting the potential of nutrient subsidies to exceed nutrients exported from the system under certain conditions. Our findings suggest that suckers have the potential to deliver large resource subsidies to their spawning habitats and that these subsidies may be ecologically important, thus warranting additional consideration of the functional relevance of nongame fishes and their migrations.

Oklahoma Bowfishing Values and Perspectives toward Nongame Fishes and Their Management

AbstractIn response to lacking information on bowfishing, bowfishers, and management planning nationwide, a survey was sent to 15,000 licensed Oklahoma anglers (bowfishers and non‐bowfishers) in 2021. Respondents (n = 1,346) were mainly male (73%) and white (74%), had an annual/5‐year license (46%) or a lifetime license (39%), and had an average age of 48 (1,182 respondents provided demographics). Questions to bowfishers gauged the importance of bowfishing compared to other fishing activities; trip frequency and motivation; where, when, and which species were targeted; the utilization of fish taken; and attitudes regarding bowfishing regulations. An estimated 24% of licensed anglers had bowfished before. Bowfishing participation in the previous year had more than doubled (4% in 2018 to 9.1% in 2020). Most (57%) had bowfished for 3 years or less; 49% identified as beginners, 43% identified as intermediate, and 8% identified as advanced. Overall, most bowfishing occurred by day (54%), in early summer (May–July), from shore (49%), and in rivers and streams (67%) or reservoirs (53%). Bowfishers sought carps (85%), gars (74%), and buffalofishes (32%). Bowfishers typically used shot fish for fertilizer or buried them (48%), used them for animal consumption (35%) or human consumption (32%), or returned them to the water (20%). Compared to non‐bowfishers, bowfishers reported a wider diversity of acceptable outcomes for fish species taken with any fishing method, particularly the nongame fishes. Most bowfishers (86%) and non‐bowfishers (94%) trusted the state management agency to appropriately manage native, nongame fishes. Bowfishers were mixed on their support for or opposition to having bowfishing regulations for these species. Some respondents noted that regulations would result in them bowfishing less (23%) or quitting bowfishing completely (6%). Thirty‐two percent of non‐bowfishers expressed interest in bowfishing in the future. The results of this survey will be used in Oklahoma and elsewhere to aid in designing sustainable bowfisheries that serve the broader public interest while conserving native, nongame species.

Microfishing for Juvenile Bluegill: A Catch‐and‐Release Study on an Emerging Form of Recreational Angling

AbstractMicrofishing is an emerging form of predominantly catch‐and‐release recreational angling with the main target being diverse small‐bodied nongame fish species and the early life stages of traditional game fish. While there has been an apparent increase in interest in microfishing, little is known about its impacts on fish and fisheries. Here we compared the effects of two hook sizes (i.e., a size 22 hook and a somewhat larger, yet still smaller than normal, size 12 hook) on aspects of injury, handling, and mortality for juvenile Bluegill Lepomis macrochirus (size range of 69 to 141 mm; n = 54 for each hook size). Hook size was determined to have a significant influence upon injury and mortality. The smaller hooks resulted in longer handling time, more extensive tissue damage arising from challenges of hook removal, and higher levels of short‐term mortality (n = 12, 22%) than the larger hooks (n = 2, 4%). Additional research is needed to develop best practices and management strategies for this emerging form of recreational angling on a wider range of species.

Abiotic and Biotic Factors Associated with Sculpin Presence and Density in Northern Idaho Streams

Sculpins (family Cottidae) are a group of small nongame fishes, native to Idaho's colder streams, and have value for biodiversity and as indicators of water quality. We analyzed abiotic and biotic data, including habitat characteristics and presence of co-occurring trout and char (family Salmonidae) species, from 115 streams from the northern Idaho Panhandle to identify the physical characteristics and biotic communities of the streams associated with sculpin presence (or absence) and population density. For comparison, and to determine if the results of the northern dataset could be attributed to the rest of the state, a second dataset from state-wide sampling was also analyzed, as was a subset of both datasets that had no observations of non-native brook trout and rainbow trout. Sculpins were more likely to be present and in higher densities in streams with abundant riffle microhabitats that were mostly free of sediment (identified as Rosgen channel types B, C, and F for northern Idaho and types B and C for the entire state). More sculpins were also found in streams lacking brook trout and rainbow trout. Knowledge of sculpin habitats and the impacts of non-native salmonids may be useful in interpreting water quality evaluations, as well as in improving native fisheries restoration projects and fisheries management for Idaho streams.

Conflicts among protected native birds and valuable sport fishes: potential pelican predation effects

Reservoirs are examples of novel ecosystems that have developed into popular sport fisheries; these systems are also becoming seasonal refuges for migratory birds, including the piscivorous American white pelican ( Pelecanus erythrorhynchos). We (1) investigated the proportion of cutthroat trout ( Oncorhynchus clarkii utah) and other species consumed by pelicans, (2) compared whether pelicans have an adverse effect on cutthroat trout spawning movement, and (3) determined the importance of pelican predation relative to other sources of fish mortality in Strawberry Reservoir, Utah, USA. Pelican diet samples consisted of >85% Utah sucker ( Catostomus ardens), 6% Utah chub ( Gila atraria), and 3% cutthroat trout. Based on bioenergetics, we estimated that pelicans consumed 384–3020 individual cutthroat trout (0.17%–1.3% of population), in contrast to 14 166–27 196 nongame sucker and chub. Bird-related mortality rate ranged from 1% to 6% for stocked, PIT (passive integrated transponder)-tagged adult cutthroat trout and from 4% to 16% for subadult cutthroat trout. Based on these results, any management action taken to control pelican predation would need to be weighed against the benefits of nongame fish removal and the protected status of pelicans.

Conservation implications of revised genetic structure resulting from new population discovery: the threatened eastern sand darter (Ammocrypta pellucida) in Canada.

Human activity can put non-game fishes at higher risk of extinction because of inappropriate management action. Eastern sand darter (Ammocrypta pellucida), a small benthic fish classified as threatened across much of its northern range, inhabits increasingly fragmented sandy habitats and, as a non-game fish, may be easily overlooked in conservation efforts. In this study, the authors use genotype data from nine microsatellite loci and cytochrome oxidase I (COI) sequencing data across its northern native range to re-assess genetic structure and to characterize a newly discovered, geographically disjunct population. Previous microsatellite marker analyses had identified seven distinct population genetic clusters across the region sampled; the analysis of this study showed that the newly discovered population (West Lake, Ontario) exhibits a divergent structure. COI haplotype analysis suggests that a single haplotype recolonized the Great Lakes and surrounding water bodies after the Wisconsinan glacial period, and subsequent fluctuation in water levels and habitat fragmentation resulted in divergence of genetic clusters. Although the novel West Lake population has a common ancestral source with other populations in the broader region, its divergent genetic signature merits its consideration as a separate conservation unit. The analyses of this study highlight the potential conservation implications of the discovery of new populations, particularly those of at-risk species, even within a region that has been genetically well characterized.

Use of Natural and Added Cover Types by Game and Nongame Fishes in a Great Plains River

AbstractThe rivers in the western Great Plains of the United States are characterized by low gradients, sandy substrates, and a relative scarcity of structural habitat. Habitat improvement projects in these systems often involve the addition of large wood and rock riprap to increase habitat for nonnative game fishes, such as piscivorous Brown Trout Salmo trutta. However, little is known about the use of added habitats by the small‐bodied nongame fishes that historically dominated the fish assemblages in these systems. We evaluated habitat availability and fish habitat use in the Laramie River (Wyoming, USA) at four sites that contained natural and added habitats. We calculated habitat selection for three natural cover types (natural wood, macrophytes, and undercut bank), two added cover types (added wood and rock riprap), and open water. Open‐water habitat dominated all sites (87–94% of the stream area), but all species except Johnny Darter Etheostoma nigrum showed negative selection for this cover type. Most species showed positive selection for both natural and added cover types but showed greater selectivity for natural wood compared to added wood. Native, small‐bodied fishes in the Laramie River used added cover types intended to benefit populations of Brown Trout. Thus, features that enhance habitat for Brown Trout also should benefit native species in Great Plains rivers that have limited natural structural habitat.

Gear effectiveness and size selectivity for five cryptic madtom species ( Noturus spp.)

More than half of the diminutive North American catfish species known as madtoms (Noturus spp.) are considered imperiled due to range reductions from habitat fragmentation and degradation. In response, government agencies regularly conduct sampling that targets these cryptic fishes. Unfortunately, the effectiveness and biases associated with common sampling gears has rarely been quantified for non-game fish, including madtoms. To improve sampling protocols for diverse madtom species, we: (a) quantified the detection probabilities and effort necessary to detect five species of madtom with relative certainty using complimentary sampling gears, and (b) described biases associated with size-selectivity of the same gears when used to sample madtoms. Five madtom species that are native to Mississippi streams and have two distinct coloration patterns were selected: uniform pattern, Brown Madtom (Noturus phaeus) and Freckled Madtom (Noturus nocturnus); patterned, Piebald Madtom (Noturus gladiator), Least Madtom (Noturus hildebrandi), and Brindled Madtom (Noturus miurus). These species were captured using four standardized sampling gears (i.e., backpack electrofisher, seine, dipnet, and Gee-style minnow trap) from 13 isolated stream reaches in Mississippi during baseflow conditions between August and November 2016. Each gear was randomly assigned to up to five transects at each site resulting in a maximum of 20 unique samples per stream reach. We estimated the detection probability of each species with each gear using presence–absence capture data. Cumulative detection probabilities were calculated for each species and gear combination to describe the number of samples necessary to achieve a detection probability of 0.95. Additionally, we pooled all capture data across sampling sites to compare madtom size distributions among gears. Electrofishing was generally the most efficient gear for detecting madtoms, but slightly overestimated fish size distributions. By seining, managers can expect to capture all species evaluated with a modest amount of effort; however, are likely to catch relatively small individuals. Seining was the most effective gear for only Piebald Madtom, a species petitioned for listing under the Endangered Species Act. To be relatively certain that Piebald Madtom are absent from a stream reach would require sampling ten 100 m transects by seining. In contrast, the same certainty would require more than twenty 100 m electrofishing transects. Minnow traps and dipnetting generally performed poorly and failed to detect some species at occupied sites. Biologists can now consider using each of these complimentary gears assessed when evaluating species status and population structure for diverse madtom species, while explicitly acknowledging the biases associated with each gear.

Behavior and Reproductive Ecology of the Sicklefin Redhorse: An Imperiled Southern Appalachian Mountain Fish

AbstractMany nongame fishes are poorly understood but are essential to maintaining healthy aquatic ecosystems globally. The undescribed Sicklefin Redhorse Moxostoma sp. is a rare, imperiled, nongame fish endemic to two southern Appalachian Mountain river basins. Little is known of its behavior and ecology, but this information is urgently needed for conservation planning. We assessed the spatial and temporal bounds of spawning migration, quantified seasonal weekly movement patterns, and characterized seasonal and spawning behavior using radiotelemetry and weir sampling in the Hiwassee River basin, North Carolina–Georgia, during 2006 and 2007. Hiwassee River tributaries were occupied predominantly during the fish's spawning season, lower reaches of the tributaries and the Hiwassee River were primarily occupied during the postspawning season (i.e., summer and fall), and lower lotic reaches of Hiwassee River (upstream from Hiwassee Lake) were occupied during winter. Adults occupied Hiwassee Lake only as a movement corridor during spawning migrations. Both sexes conducted upstream spawning migrations simultaneously, but males occupied spawning tributaries longer than females. Sicklefin Redhorse exhibited interannual spawning‐area and tributary fidelity. Cold water temperatures associated with hypolimnetic releases from reservoirs and meteorological conditions influenced spawning migration distance and timing. During 2007, decreased discharges during the spawning season were associated with decreases in migration distance and spawning tributary occupancy duration. Foraging was the dominant behavior observed annually, followed by reproductive behaviors (courting and spawning) during the spawning season. No agonistic reproductive behavior was observed, but females exhibited a repetitious postspawning digging behavior that may be unique in the family Catostomidae. Our findings suggest that protection and restoration of river continuity, natural flow regimes, seasonally appropriate water temperatures, and geographic range expansion are critical components to include in Sicklefin Redhorse conservation planning. Fisheries and ecosystem managers can use our findings to justify sensitive management decisions that conserve and restore critical streams and rivers occupied by this imperiled species.

Survival of Upper Piedmont Stream Fishes Implanted with 8‐mm Passive Integrated Transponder Tags

AbstractWe studied weekly and bimonthly survival of select nongame fishes that were implanted with 8‐mm PIT tags in upper Piedmont streams of South Carolina, USA. Weekly survival in stream enclosures was assessed for a total of 350 tagged individuals and 311 control (untagged) fish (39–101 mm TL; median = 65 mm TL) belonging to six species (Bluehead Chub Nocomis leptocephalus, Creek Chub Semotilus atromaculatus, Yellowfin Shiner Notropis lutipinnis, Mottled Sculpin Cottus bairdii, Northern Hog Sucker Hypentelium nigricans, and Striped Jumprock Moxostoma rupiscartes). Weekly survival rates ranged from 93.3% to 100% among species, with Yellowfin Shiners experiencing the lowest survival rate. Only 2 of the 337 surviving tagged individuals lost their tags (0.6% tag loss). Logistic regression indicated that species and body length were statistically significant predictors of survival and tag retention. Odds ratios indicated that tagged fish were 1.718 times less likely to survive than control fish, but the tagging effect was not statistically significant. Bimonthly survival was estimated by conducting a mark–recapture study from September 2015 to May 2016, which involved tagging 1,413 unique individuals of Bluehead Chub (45–75 mm TL) in a 520‐m stream section and 431 individuals of Mottled Sculpin (45–75 mm) in another 740‐m section. Bayesian state–space analysis of Cormack–Jolly–Seber models indicated that apparent survival did not differ between newly tagged and previously tagged (i.e., recaptured) individuals in any sampling interval, suggesting that the acute and chronic effects of tagging did not differ. Mean bimonthly apparent survival rate was 0.76 (95% credible interval = 0.64–0.86) for Bluehead Chub and 0.74 (95% credible interval = 0.59–0.88) for Mottled Sculpin. Our results indicate that PIT tags can be successfully applied to study the ecology and life history of small‐bodied, nongame fish species, although caution should be exercised when selecting the species and body sizes to be tagged.

Complex postglacial recolonization inferred from population genetic structure of mottled sculpin Cottus bairdii in tributaries of eastern Lake Michigan, U.S.A.

This study used analyses of the genetic structure of a non-game fish species, the mottled sculpin Cottus bairdii to hypothesize probable recolonization routes used by cottids and possibly other Laurentian Great Lakes fishes following glacial recession. Based on samples from 16 small streams in five major Lake Michigan, U.S.A., tributary basins, significant interpopulation differentiation was documented (overall FST = 0·235). Differentiation was complex, however, with unexpectedly high genetic similarity among basins as well as occasionally strong differentiation within basins, despite relatively close geographic proximity of populations. Genetic dissimilarities were identified between eastern and western populations within river basins, with similarities existing between eastern and western populations across basins. Given such patterns, recolonization is hypothesized to have occurred on three occasions from more than one glacial refugium, with a secondary vicariant event resulting from reduction in the water level of ancestral Lake Michigan. By studying the phylogeography of a small, non-game fish species, this study provides insight into recolonization dynamics of the region that could be difficult to infer from game species that are often broadly dispersed by humans.

Mapping ecosystem service indicators in a Great Lakes estuarine Area of Concern

Abstract Estuaries provide multiple ecosystem services from which humans benefit. Twenty-seven Great Lakes coastal systems in the United States and Canada, many of them estuarine, are currently designated as Areas of Concern (AOCs) due to a legacy of chemical contamination, degraded habitat, and non-point-source pollution. The ecosystem benefits that current and future human communities can receive from these degraded ecosystems are diminished. For an AOC to be delisted, it is generally necessary to restore aquatic habitat, among other actions. Ecosystem service mapping and assessment can inform AOC restoration and management. We describe an approach, with examples, for assessing how local-scale actions affect the extent and distribution of coastal ecosystem services, using the estuarine portion of St. Louis River AOC of western Lake Superior as a case study. We applied mapping criteria derived from locally validated predictive models, published relationships, local experts, and other sources to spatially explicit biophysical data to map indicators of ecosystem services at high resolution across aquatic and riparian habitats. We mapped indicators for 23 biophysical services in the estuary (e.g., natural views, boating, game and non-game fish and wildlife species, wild rice, parks and trails, beaches, property protection, sacred sites). Most 10 × 10 m aquatic pixel locations had 3–7 overlapping services; riparian locations had fewer mapped services. To examine tradeoffs in services associated with management actions, we quantified the changes in the area of the AOC providing each ecosystem service for scenarios based on planned sediment remediation and habitat restoration projects. Some aspects of our approach can be adapted by Great Lakes coastal communities to support local environmental decision-making.

Distributions of Small Nongame Fishes in the Lower Yellowstone River

Abstract The Yellowstone River is the longest unimpounded river in the conterminous United States. It has a relatively natural flow regime, which helps maintain diverse habitats and fish assemblages uncommon in large rivers elsewhere. The lower Yellowstone River was thought to support a diverse nongame fish assemblage including several species of special concern. However, comprehensive data on the small nongame fish assemblage of the lower Yellowstone River is lacking. Therefore, we sampled the Yellowstone River downstream of its confluence with the Clark’s Fork using fyke nets and otter trawls to assess distributions and abundances of small nongame fishes. We captured 42 species (24 native and 18 nonnative) in the lower Yellowstone River with fyke nets. Native species constituted over 99% of the catch. Emerald shiners Notropis atherinoides, western silvery minnows Hybognathus argyritis, flathead chubs Platygobio gracilis, sand shiners Notropis stramineus, and longnose dace Rhinichthys cataractae composed...

Using Historical Atlas Data to Develop High-Resolution Distribution Models of Freshwater Fishes.

Understanding the spatial pattern of species distributions is fundamental in biogeography, and conservation and resource management applications. Most species distribution models (SDMs) require or prefer species presence and absence data for adequate estimation of model parameters. However, observations with unreliable or unreported species absences dominate and limit the implementation of SDMs. Presence-only models generally yield less accurate predictions of species distribution, and make it difficult to incorporate spatial autocorrelation. The availability of large amounts of historical presence records for freshwater fishes of the United States provides an opportunity for deriving reliable absences from data reported as presence-only, when sampling was predominantly community-based. In this study, we used boosted regression trees (BRT), logistic regression, and MaxEnt models to assess the performance of a historical metacommunity database with inferred absences, for modeling fish distributions, investigating the effect of model choice and data properties thereby. With models of the distribution of 76 native, non-game fish species of varied traits and rarity attributes in four river basins across the United States, we show that model accuracy depends on data quality (e.g., sample size, location precision), species’ rarity, statistical modeling technique, and consideration of spatial autocorrelation. The cross-validation area under the receiver-operating-characteristic curve (AUC) tended to be high in the spatial presence-absence models at the highest level of resolution for species with large geographic ranges and small local populations. Prevalence affected training but not validation AUC. The key habitat predictors identified and the fish-habitat relationships evaluated through partial dependence plots corroborated most previous studies. The community-based SDM framework broadens our capability to model species distributions by innovatively removing the constraint of lack of species absence data, thus providing a robust prediction of distribution for stream fishes in other regions where historical data exist, and for other taxa (e.g., benthic macroinvertebrates, birds) usually observed by community-based sampling designs.

Ecological factors influencing movement of creek chub in an intermittent stream of the Ozark Mountains, Arkansas

AbstractIncreasing our understanding of the traits and adaptations that promote the survival and persistence of organisms in highly dynamic environments will aid in the conservation of populations and communities. Projected effects of climate change and land alterations suggest headwater streams may become more intermittent and less predictable, consequently altering biological processes (i.e. dispersal or movement) that govern population dynamics. Few studies have provided insight into movement dynamics of nongame fishes in small headwater streams that commonly experience intermittent conditions. The purpose of this study was to investigate movement of a fish species adapted to intermittent stream conditions. Our objectives were to (i) describe the general movement patterns of creek chub, Semotilus atromaculatus, in an intermittent stream and (ii) investigate which ecological factors may influence movement in patchy environments. Creek chub displayed some of the longest distances moved compared to many other stream fishes in perennial streams (179–1069 m seasonal averages; 4678 m maximum distance). Directional movement was significant only in May with more individuals moving upstream. The probability of creek chub movement was inversely related to habitat complexity and pool area. Creek chub adapted to intermittent stream conditions not only exhibited increases in the frequency and distance of movement compared to other nongame fishes, but also exhibited movements in relation to local habitat metrics. These results demonstrate some of the potential adaptations that are likely to promote the survival and persistence of populations in highly dynamic environments such as intermittent streams.