Relative weight (Wr) is an index that is commonly used by fisheries managers to evaluate the condition within and among fish populations. Managers also use Wr comparisons to assess condition dynamics among species. Rather than using population‐level mean Wr for comparisons, standard length categories are frequently used to evaluate mean Wr differences among length categories. To establish Wr values

Invasive species can have varying and unpredictable reproductive potential among native and invaded populations or along invasion fronts, potentially contributing to invasion success. Understanding the reproductive potential (fecundity and egg size) of low‐density, leading‐edge populations is important to inform the management of Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis populations

Advantages of PIT tags are their small size, longevity, and low cost compared to other tags. They are often used in fisheries to study movement patterns and survival or to estimate population size. However, PIT tags are limited by their short detection distance. Mobile PIT antennas may increase the utility of PIT tags in fisheries. In this study, we synthesized current detection efficiency literature

Size‐selective harvest in a fishery is a growing point of contention among different catfish anglers. In response to these concerns, size‐specific exploitation rates of Flathead Catfish and Blue Catfish by recreational anglers and commercial fishers were quantified. Eight study reaches were randomly selected on the Missouri River (4 reaches; recreational harvest only) and Mississippi River (4 reaches;

Habitat loss is a main contributor to fish fauna declines in the southwestern USA. Several studies have defined stream‐specific habitat conditions that support the growth and survival of native fish in Arizona to inform stream restoration efforts, yet general habitat use of most individual species across the region is not established. Therefore, we evaluated habitat use of four native fishes, Speckled

The role that open‐net‐pen farms for Atlantic Salmon Salmo salar play in the global decline of stocks of wild salmonids (Salmo spp. and Oncorhynchus spp.) is contentious; Canada’s west coast is no exception. We identified the proportion of acoustic‐tagged juvenile Sockeye Salmon Oncorhynchus nerka migrating through the main migration routes of the Discovery Islands region of British Columbia and measured

Straying has been difficult to study directly in natural steelhead Oncorhynchus mykiss populations. We analyzed an opportunistic sample of seven adult steelhead from a small basin on the Big Sur coast of California to determine their life history traits, including whether they were strays. Otolith natural tags (87Sr/86Sr) and genetic stock identification indicated that all seven adults were strays

Invasive carp are expanding throughout the upper Mississippi River basin and are of great concern due to their potential economic and ecological impacts. Identification of spawning locations provides critical information on recruitment sources to evaluate potential management strategies. Our objective was to create and validate a spawning habitat suitability model of the Des Moines River, Iowa, during

Three species of invasive carp, Grass Carp (Ctenopharyngodon idella), Silver Carp (Hypophthalmichthys molitrix), and Bighead Carp (H. nobilis), are rapidly spreading throughout North America. Monitoring reproduction can help determine establishment in new areas but is difficult due to challenges associated with identifying fish eggs. Recently, random forest models provided accurate identification of

Brook Trout Salvelinus fontinalis have declined across their native range due to multiple anthropogenic factors, including landscape alteration and climate change. Although coldwater streams in the State of Maryland (eastern United States) historically supported significant Brook Trout populations, only fragmented remnant populations remain with the exception of the upper Savage River watershed in

Identifying sex in salmonids using non‐lethal methods is valuable for controlled breeding in aquaculture and understanding behavior and dispersal for conservation. Although salmonids are male heterogametic, genetic sex identification has been problematic because a specific sex determination locus has been elusive. We implemented a blind analysis to identify sex in Brook Trout Salvelinus fontinalis

The management of invasive Blue Catfish Ictalurus furcatus in Chesapeake Bay tributaries is hindered by the lack of information on its reproductive biology, which is a key component of population models used to forecast abundance. We quantified and compared the reproductive traits of female Blue Catfish from two populations from the tidal reaches of the James and York river subestuaries, during 2015‐2017

Reliable fish tagging methods are needed to conduct studies (e.g., movement, habitat, abundance) that inform conservation and management decisions; however, dependable tagging approaches are lacking for many small‐bodied fishes. Therefore, our study objective was to determine survival, tag retention (Visible implant elastomer [VIE], passive integrated transponder [PIT], or p‐Chip), and tagging effects

Catfishes (family Ictaluridae) are among North America’s most important icthyofauna for human consumption and recreation. As such, research of Blue Catfish Ictalurus furcatus, Channel Catfish I. punctatus, and Flathead Catfish Pylodictis olivaris has been abundant in historic and contemporary literature. A common technique for studying catfish involves marking or tagging fish to understand behavior

Stream drying, especially in the western United States, is becoming more common as the climate warms and precipitation patterns become less predictable; consequently, fisheries managers need to prioritize conservation efforts where water (and fish) will persist in the future. Yellow Creek in the upper Bear River watershed (Utah and Wyoming) contains one of the largest remaining populations of Northern

Bigheaded carps (BHCs; Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis) are economically and culturally important in Asia and Europe but are considered highly invasive throughout the Mississippi River watershed and pose a threat to the food web and fisheries of the Laurentian Great Lakes. We used the Ecopath with Ecosim model framework to evaluate potential risk of BHC population

Angling catch rates of Walleye Sander vitreus in many lakes across Alberta have increased dramatically in the past 20 years, following their collapse and then recovery after implementation of restrictive harvest regulations. With increased abundance, some anglers are concerned that Walleyes may negatively affect abundance of Northern Pike Esox lucius. To address this hypothesis, we looked at net catch

Relatively little research exists for lentic populations of Flathead Catfish Pylodictis olivaris, particularly in northern states such as Iowa, which currently has no harvest restrictions and a growing interest in trophy opportunities. We assessed size and age structure, growth, condition, and survival for Flathead Catfish populations in Lake Red Rock and Rathbun Lake to increase our understanding

In the western United States, the introduction of nonnative Brook Trout Salvelinus fontinalis has had deleterious effects on native Cutthroat Trout Oncorhynchus clarkii subspecies, and often their populations must be controlled or removed if Cutthroat Trout are to persist. Man‐made fish migration barriers are integral components of stream restoration projects, and typical designs are intended to be

Projected intensification of drought as a result of climate change may reduce the capacity of streams to rear fish, exacerbating the challenge of recovering salmonid populations listed under the Endangered Species Act. Without management intervention, some stocks will likely go extinct as stream drying and fragmentation reduce juvenile survival to unsustainable levels. To offset drought‐related mortality

In live‐release angling tournaments, fish are captured and typically held within onboard live‐well systems, where they are subsequently “culled” (i.e., released) as larger fish are captured. Anglers often mark individual fish to easily identify them based on weight and to reduce handling time. However, there is limited information about the physiological consequences of using different culling apparatus

We examined patterns in the somatic growth of populations of Largemouth Bass Micropterus salmoides in northern Idaho lakes and modeled its variation to understand how spatiotemporal differences in climate regulate growth in lentic systems. Age was estimated from 768 Largemouth Bass from six distinct populations. Largemouth Bass growth and longevity in northern Idaho was typical to populations at similar

Although the use of electric fish handling gloves (EFHGs) has been advocated as a no‐residue alternative to chemical immobilization for field studies, the impact of their use on fish welfare remains uncertain for surgical procedures. The effects of EFHGs (10–16 mV), with and without local infiltration of lidocaine (6 mg/kg), on stress and muscle integrity after the surgical implantation of an intracoelomic

Coarse woody habitat (CWH) in aquatic ecosystems provides structural complexity and a surface for food production for fish. Depending on abundance and complexity of CWH, it is usually associated with influencing predator–prey dynamics, fostering greater localized fish abundance, increasing fish growth, and contributing to fish production, but some conflicting evidence exists about its importance as

Inferences based on tagged individuals from a population are limited in part by the minimum size of fish that can be tagged. Smaller tags allow a greater proportion of a population to be represented by tagging and should reduce potential tag effects on fish performance. We evaluated different performance metrics of juvenile fall Chinook Salmon Oncorhynchus tshawytscha tagged with 8‐, 9‐, and 12‐mm

Members of the freshwater catfishes (order Siluriformes) are capable of transintestinal expulsion of foreign bodies, including internally implanted tags, which can bias movement and survival estimates. We evaluated long‐term (120‐week) retention rates of passive integrated transponder (PIT) tags in a laboratory setting to assess potential tag loss in Stonecat Noturus flavus. The PIT tags were surgically

Bluegill Lepomis macrochirus and Redear Sunfish L. microlophus are highly regarded recreational species throughout North America. Management of these species relies on sampling methods that accurately and efficiently describe population characteristics of the target population. Largemouth Bass Micropterus salmoides and crappies Pomoxis spp. are commonly sampled with spring electrofishing and fall fyke

The first marginal pectoral fin ray (fin spine) is the most common structure used for estimating the age of sturgeons, including Lake Sturgeon Acipenser fulvescens. However, conflicting results from studies on the effects of fin spine removal have made some managers hesitant about the practice. We investigated whether the second pectoral fin ray, which can be removed in a less invasive procedure, could

Walleye Sander vitreus are commonly introduced to reservoirs and provide valued fisheries. Walleye are lost though harvest and natural mortality in all systems, but escapement may also reduce reservoir populations. However, the effects of harvest, natural mortality, and escapement loss on reservoir Walleye populations are not known. Our objective was to quantify Walleye harvest, natural mortality,

Bullheads Ameiurus spp. are found throughout much of the United States and are an infrequently studied species. Although limited information has been published on Black Bullheads Ameiurus melas and Yellow Bullheads A. natalis, it has been shown that bullheads can dominate the fish biomass in some north temperate USA lakes resulting in a fish community exclusive of Walleye Sander vitreus and Yellow

North American fisheries management agencies commit considerable resources to managing reservoir Channel Catfish Ictalurus punctatus fisheries, which often includes stocking. However, Channel Catfish population characteristics often vary greatly among reservoirs, resulting in variable and unpredictable fishery quality. We sampled Channel Catfish populations in 44 Ohio reservoirs with tandem, baited

We used historical stocking and population survey records of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri and other salmonids in the North Fork Shoshone River Drainage, Wyoming, to summarize fish stocking history and population trends. Based on 98 years of historical records, we found that despite extensive stocking of Yellowstone Cutthroat Trout and minimal stocking of non‐native salmonids

Black bass Micropterus spp. in North America are commonly targeted by recreational anglers participating in catch‐and‐release angling tournaments. In deeper waterbodies, Smallmouth Bass Micropterus dolomieu are often caught from depths greater than 6 m and held in a boat’s livewell until they are weighed‐in. Smallmouth Bass caught from such depths typically display symptoms of barotrauma, where the

Riverine Channel Catfish Ictalurus punctatus are largely unregulated in West Virginia USA, while recreational angling interest for the species is emerging. This study focuses on hoop net assessments of the species’ size structure and abundance across a longitudinal continuum of the fifth‐order, low‐moderate gradient South Branch of the Potomac River (SBR). Population growth, annual mortality, angler

In 2015, the Illinois Department of Natural Resources changed size and harvest limits for catfishes (Blue Catfish Ictalurus furcatus, Flathead Catfish Pylodictis olivaris, and Channel Catfish Ictalurus punctatus) in the lower Ohio River to match those of neighboring states. The new regulations imposed a daily limit of one Blue Catfish or Flathead Catfish ≥ 35 inches (88.9 cm) and one Channel Catfish ≥

The establishment of non‐native predator fish is a worldwide phenomenon often having adverse effects on native species. Trophic interactions are complex, and uncertainty is a common theme in discussions of non‐native predator management. Several fishes of the San Francisco Estuary have experienced significant declines in recent decades due to multiple factors, including habitat alteration and predation

The Alaska salmon hatchery program is intended to supplement salmon fisheries without supplanting wild stocks. Hatchery‐origin Chum Salmon spend most of their lives interacting with wild salmon, including some degree of straying to spawning streams. Our study was designed and implemented to measure the extent and annual variability of straying by hatchery‐produced summer‐run Chum Salmon in Southeast

Fisheries managers efficiently sample reservoir Channel Catfish populations with tandem, baited hoop nets. However, catchability (the fraction of a fish stock caught with a defined unit of effort) of Channel Catfish with this gear and the size selectivity of this gear are not fully known. Further, scientists have not identified a standard sampling period that maximizes catches while minimizing variation

A series of rock jetty and A‐Jack structures was built in 1998 at Branched Oak Reservoir, Nebraska, in an attempt to reduce shoreline erosion and cove degradation. In conjunction with the habitat enhancement project, Flathead Catfish Pylodictis olivaris were stocked to help control the abundant White Perch Morone americana population. Previous research found that Flathead Catfish utilized the habitats

Minimizing the mortality and migration time of juvenile salmon (smolts) passing dams is a longstanding objective in the pursuit of salmon recovery in the Columbia River Basin. We compiled and analyzed 40 juvenile salmonid acoustic‐tag studies that were performed at seven of the eight hydroelectric projects in the Federal Columbia River Power System between 2010–2018. We found the utilization of non‐turbine

Fisheries managers are devoting considerable effort, time, and funding towards limiting the spread of invasive Bighead and Silver (bigheaded) Carp. A better understanding of factors that influence spatial patterns of bigheaded carp reproduction can help fisheries managers prevent their spread. To examine factors that influence spatial patterns of reproduction, we sampled ichthyoplankton using drift

The premise of catch‐and‐release recreational angling is that postrelease survival is high. Therefore, it is common for anglers, management agencies, and conservation organizations to share information on handling practices and other strategies that are believed to improve the welfare and survival of fish that are released. A recent surge in popularity has sensationalized the use of carbonated beverages

Density‐dependent growth has been well documented among stream‐dwelling Brown Trout Salmo trutta populations. In Spearfish Creek, South Dakota, biomass of adult Brown Trout (>200 mm) is about three times greater than that reported for similar Black Hills streams, whereas the mean length of adult fish is about 30% less. Here, we evaluate density reduction as a management tool for improving the growth

Measuring fishing effort is a common practice in fisheries management. Traditional access‐point or roving creel surveys rely on in‐person interaction between management agency personnel and anglers, the cost of which can restrict where and when the surveys can be performed. Increasing the efficiency of the techniques that are used to estimate recreational fishing effort would benefit management agencies

This study developed a spatially explicit framework to support the conservation of Western Brook Lamprey Lampetra richardsoni and Pacific Lamprey Entosphenus tridentatus in the Umpqua River basin, Oregon. This framework identified locations within the river network likely to support “potential burrowing habitat” for lamprey larvae based on geomorphic conditions and evaluated the overlap of potential

The Jonah crab Cancer borealis is a data‐poor species with an unknown stock status. They were historically caught as bycatch in American lobster Homarus americanus traps. The decline of the southern New England lobster stock since 1990 helped stimulate a targeted fishery and a sixfold increase in both the landings and ex‐vessel value of Jonah crab. Current knowledge on Jonah crab growth and reproduction

Entrainment at hydropower facilities, where fish (volitionally and nonvolitionally) enter hydropower infrastructure such as intake towers, can lead to fish becoming stranded for considerable periods of time rather than being flushed to downstream areas. To reduce fish injury and/or mortality from entrainment stranding events, hydropower operators will salvage stranded fish and release them back into

Hatchery augmentation of dwindling wild populations has become a common strategy to avoid extinction of endangered fishes. While benign hatchery conditions can lead to low persistence of stocked individuals, experiments have demonstrated that flow conditioning of Razorback Sucker Xyrauchen texanus can increase swimming performance and reduce downstream movements from desired locations after stocking

Due to time and resource limitations, the growth of many fish species is evaluated with age and length data in a length‐stratified subsample of a sample from a population. Some fisheries professionals draw inferences about growth using age and length data from only those fish that were actually aged (aged‐only method). Alternatively, growth may be evaluated by employing a method of incorporating the

When performing studies that require fish age estimation, biologists must achieve a high level of accuracy and precision, as age, growth, and survival data are often used in models that inform management decisions. Otolith processing techniques vary, and no studies have assessed which methodology is more precise and cost effective. Our goal was to assess the precision, effort, and resources needed

Fishing in streams and rivers is a popular outdoor recreation activity in eastern Oklahoma, where most anglers target black bass (Micropterus) species. Since the early 1990s, when the last assessment of black bass fishing in the region was conducted, broadscale factors such as harvesting behavior, state fishery regulations, and bass population dynamics have changed. In 2018, we conducted creel and

Stocking Rainbow Trout Oncorhynchus mykiss to create additional angling opportunities is common; however, the spatial and temporal dynamics of such stocking practices are unclear in groundwater‐influenced, warmwater streams. Our objectives were to determine Rainbow Trout dispersal from a stocking location on Spavinaw Creek, Oklahoma and to quantify apparent survival of two cohorts of Rainbow Trout

After centuries of declines, there is growing interest in conserving extant wild populations of Brook Trout Salvelinus fontinalis and reintroducing Brook Trout populations of native ancestry. A population genetic baseline can enhance conservation outcomes and promote restoration success. Consequently, it is important to document existing patterns of genetic variation across the landscape and translate

Southwest Virginia offers a plethora of fishing opportunities for wild trout (Brook Trout Salvelinus fontinalis, Brown Trout Salmo trutta, and Rainbow Trout Oncorhynchus mykiss) in headwater and large valley floor streams. However, low productivity in most area streams, including the South Fork Holston River, limits growth leading to populations where individuals seldom exceed 25 cm. The Buller Fish

Muskellunge Esox masquinongy are large piscivores stocked into numerous lakes in North America, but the potential effects of these stockings remains poorly understood. To investigate potential fish community changes associated with Muskellunge stocking, we contrasted catch per unit effort (CPUE) for seven fish species commonly found in Minnesota, along with mean weight for two predator species, before

In diet studies, stomach contents from predatory fish may be difficult to identify due to digestion. The Gizzard Shad Dorosoma cepedianum is an important prey species for sport fish; thus, determining the size of ingested shad can assist with evaluating competitive interactions, bioenergetic patterns, and niche partitioning and can add precision to predictive models. The gizzard organ of clupeids appears

Managing fisheries for species of conservation concern, such as steelhead Oncorhynchus mykiss fisheries in Idaho where wild steelhead are incidentally caught and released, requires a tradeoff between providing opportunity for anglers to fish for hatchery‐origin steelhead and managing conservation risk for wild steelhead. Understanding population‐level effects of catch‐and‐release fishing is critical

Loss of habitat, targeted removals, and overharvest has contributed to the decline of Alligator Gar Atractosteus spatula. There is agreement among commercial fishers, some recreational anglers, conservationists, and natural resource managers that this species warrants conservation. Appropriate management actions require research to further understand the life history and ecology of Alligator Gar populations

The Grass Carp Ctenopharyngodon idella is an invasive species to the Laurentian Great Lakes that was first detected in the 1980s. The western basin of Lake Erie is the putative invasion front for the Great Lakes, with spawning known to occur in two of the basin’s tributaries (Sandusky and Maumee rivers). Targeted removal is being used to reduce Grass Carp abundance, with an ultimate aim of eradication

Rocky reef habitats in lacustrine systems constitute important areas for lithophilic‐spawning fishes. Interstitial spaces created by the structure of rocky reefs form microenvironments where incubating embryos and juvenile fish are potentially protected from predators and physical displacement. However, if interstitial spaces are filled or blocked by sediment or biofouling, the reef structure may lose