Abstract Objective To determine (1) if average catch rates or average weight of black bass Micropterus spp. differed between periods of live-imaging sonar (LIS) use and nonuse for avid anglers across a diverse range of fisheries and (2) if the frequency of LIS-facilitated catches was associated with specific fishing habitat characteristics. Methods We analyzed catch data from professional anglers across eight Major League Fishing events in 2025. The tournament rules restricted the use of LIS to one of three daily competition periods. A linear mixed-effects model was used to assess if LIS had an effect on catch or fish weight. The fixed effects included LIS use, fishery, and tournament day, with an interaction term used to evaluate whether LIS efficacy was contingent on specific fisheries. To account for repeated measures and individual angler skill, angler identity as a random effect was used. We also explored how selected habitat aspects of fisheries related to the use of LIS to catch black bass. Contingency analyses were used to examine relationships with water body type, habitat cover complexity, and water depth. Results The influence of LIS on catch rates varied by fishery, with notable increases occurring at Lakes Conroe and Murray. Generally, the weight of the black bass that were caught did not significantly differ between LIS and non-LIS periods. A greater percentage of black bass was caught by anglers who were using LIS in areas that were ranked as lentic water versus rivers or creeks as well as in low-complexity habitat cover. Additionally, anglers who caught fish in deep water had nearly three times the likelihood of using LIS. Conclusion Although anglers were more likely to catch fish with LIS in deeper, less structured environments, it appears to offer limited utility in shallow, complex shoreline habitats. Therefore, the risk of increased exploitation due to LIS may be inherent in fisheries with deeper, less structured habitats or seasonal pelagic opportunities. By standardizing angler avidity and accounting for angler skill in our models, this study provides an isolated measure of LIS use and benefit. This highlights the necessity for fisheries managers to account for avidity bias and water body morphology when considering the effects of widespread adoption of LIS in a fishery.
Abstract Objective Passive integrated transponder (PIT) tags are used in fisheries studies to estimate population demographics, track movement, and assess stocking programs. Retention of PIT tags is dependent upon tag size and location, emphasizing the need for species- and size-specific retention studies to understand tagging limitations and implications to mark–recapture data. Implanted tags generally have high retention rates and minimal effects on large-bodied fish, while larger tags in small-bodied fish may result in negative side effects (slower growth, high posttagging mortality). Additionally, there is often a trade-off between tag retention and detection with different tag sizes (i.e., decrease in tag size results in decrease in tag detection). Therefore, the objective of this study was to determine if fish length, PIT tag size (8 mm or 12 mm), and/or tagging additive (i.e., n-butyl-cyanoacrylate surgical adhesive at the tag insertion point) influences tag retention, growth, and survival of age-0 Lake Sturgeon Acipenser fulvescens. Methods We implanted 293 fish ranging from 75 to 205 mm total length (TL) with 8- and 12-mm PIT tags, with half the fish from each treatment group receiving n-BCA surgical adhesive at the tag insertion point. To determine if growth was influenced by treatment group, TL and weight were compared between the beginning and end of the study. Tag loss was monitored daily in a controlled hatchery environment for 84 to 98 d after tagging. Results Tag retention increased as TL increased and was lower in the 12-mm n-butyl-cyanoacrylate treatment group when compared with all other treatments. Tag loss was greatest within 14 d posttagging, but fish continued to lose tags up to 63 d after tagging. No growth differences were observed between treatment and control groups. Retention of 8-mm PIT tags was greater than 12-mm tags; however, 100% retention was observed in fish >175 mm TL, irrespective of tag size. Conclusions When possible, we suggest implanting age-0 Lake Sturgeon with larger PIT tags at a size >175 mm TL to increase retention and detection rates. Lastly, holding fish up to 14 d after tagging could reduce poststocking tag loss and better inform future stocking program evaluations.
Abstract Objective Invasive Common Carp Cyprinus carpio cause lake management challenges in the Midwestern United States including increased turbidity and decreased macrophyte abundance and growth. Although they are native and long-lived in this region, overabundant, zooplanktivorous Bigmouth Buffalo Ictiobus cyprinellus may indirectly contribute to eutrophication by releasing algae from grazing pressure and are targeted by commercial fishers due to high market prices. Individual tools for managing these species (e.g., fish barriers, toxicants, harvest) have had limited utility for improving water quality and sport fisheries in Iowa, but there may be promise in integrating these methods. Our study tested whether integrating lake restoration techniques affected water quality, sport fisheries, and macrophytes in Lost Island Lake, Iowa. Methods We present a case study of multifaceted management in which Common Carp and Bigmouth Buffalo were simultaneously subjected to spawning-access restrictions, commercial harvest, rotenone, and increased piscivore densities. We used a treatment–reference lake design along with generalized linear models and generalized linear mixed models to compare water quality parameters, fish relative abundance, and macrophyte species richness and coverage before and after lake restoration efforts. Results From pre- to postrestoration, there was a significant increase in Secchi depth and significant decreases in chlorophyll-a, nitrate nitrogen, pH, total suspended solids, and turbidity. We observed significant, sustained increases in the relative abundance of socioeconomically valuable sport fish (i.e., Black Crappie Pomoxis nigromaculatus, Bluegill Lepomis macrochirus, Largemouth Bass Micropterus nigricans, White Bass Morone chrysops, Yellow Bass M. mississippiensis, and Yellow Perch Perca flavescens) when Common Carp and Bigmouth Buffalo were less abundant. The macrophyte community—defined solely by cattails Typha spp. before restoration—became more diverse, with native species such as sago pondweed Stuckenia pectinata expanding considerably after restoration. Conclusions Our results underscore the importance of integrating fisheries management techniques—including fish barriers and water-level control structures, incentivized (subsidized) commercial harvest, targeted rotenone application, and piscivore stocking—to improve water quality and sport fisheries. The longevity of this multifaceted approach to management was notable, with benefits to Lost Island Lake lasting more than 10 years. Our study provides a foundation on which to expand the scope of multifaceted fisheries management by testing these methods in lakes along gradients of productivity, morphometry, and geography.
Abstract Objective Stocking can produce new fisheries, but high niche overlap between stocked and resident species may cause competition that inhibits stocking goals and harms existing fisheries. Thus, stocking of Blue Catfish Ictalurus furcatus in reservoirs to create fisheries could intensify interspecific competition that results in failed fishery development and reduced growth of resident species. Given this potential, we characterized the trophic ecology of Blue Catfish and other sport fishes in two Ohio reservoirs—one with (Hoover Reservoir) and one without (Alum Creek Lake) an established Blue Catfish population. Methods We used stable isotopes (δ13C, δ15N, and δ34S) and diet data to quantify the trophic niches of Blue Catfish, Channel Catfish I. punctatus, Largemouth Bass Micropterus nigricans, crappies Pomoxis spp., and saugeye (Sauger Sander canadensis × Walleye S. vitreus) collected seasonally from summer 2022 through autumn 2024. We quantified the isotopic niches of all species, comparing their size and overlap within and between reservoirs. We used isotopic mixing models and diet analyses to understand the energy pathways underlying observed niche patterns. Results Niche size and overlap varied within and between reservoirs. In Hoover Reservoir, ictalurid niches overlapped and the Channel Catfish niche was larger than those of other sport fish; neither ictalurid niche overlapped with the niches of other sport fish. In Alum Creek Lake, the Channel Catfish niche was larger than the niches of all other sport fishes, with little overlap. Gizzard Shad Dorosoma cepedianum was the primary energy source in both reservoirs, although macroinvertebrates were consumed more in Hoover Reservoir (with established Blue Catfish) despite a higher prey fish density than in Alum Creek Lake. Conclusions Our findings show the potential for competition for prey between Blue Catfish and Channel Catfish, whereas the potential of either ictalurid to compete with other sport fishes for prey is unlikely. Thus, reservoirs that are best suited for creating a successful Blue Catfish fishery without harming existing sport fisheries may be those with abundant prey and small Channel Catfish populations.
Abstract Objective This study aimed to quantify the physiological and behavioral responses of Largemouth Bass Micropterus nigricans to reductions in temperature during simulated live-well holding following exercise. Methods We first acclimated Largemouth Bass to three temperatures (15°C, oscillating between 10°C and 20°C, and 25°C) that represent seasonal conditions in the Midwestern United States and then subjected them to exhaustive exercise and brief air exposure (angling simulation). Following this angling simulation, one group of fish was placed in a dynamic shuttle box system to identify the temperature they preferred while recovering from exercise. A second group of fish was placed into intermittent flow respirometry to quantify the metabolic consequences of an acute cooling event during recovery after exercise and then experienced an increase in temperature that simulated release at the conclusion of a tournament into a warmer water body. Results After a simulated angling event, Largemouth Bass preferred to recover at temperatures above their acclimation temperature. In addition, Largemouth Bass that experienced a reduction in water temperature after exercise had prolonged recovery times and a reduced aerobic scope compared with fish that recovered at acclimation temperature. Largemouth Bass that were cooled during recovery and then warmed, simulating a return to an epilimnion after being in a cool live well, experienced a metabolic shift. Conclusions Largemouth Bass prefer to recover in water slightly warmer (2–4°C) than their acclimation temperature, likely to facilitate recovery from physiological alterations after exercise. Cooling of live wells in angling tournaments delays the recovery of fish, and returning cool fish to a warmer ambient water body results in a thermal challenge that prolongs recovery time. Anglers should refrain from cooling their live wells and should focus on maintaining live-well temperatures near that of the epilimnion where Largemouth Bass are captured.
Abstract Objective Accurate and precise age estimation is essential for understanding early life history, recruitment, and population dynamics in fish. However, daily otolith increment deposition has not been validated for Grass Carp Ctenopharyngodon idella in the Midwestern United States. Our objective was to validate daily increment deposition in lapilli otoliths of known-age Grass Carp that were reared under controlled laboratory and outdoor pond environments and to evaluate the reliability of otolith-based daily age estimation across early life stages. Methods Larval Grass Carp that were hatched from captive broodstock were reared in indoor tanks and outdoor ponds and sampled between 6 and 120 d posthatch. The lapilli otoliths were extracted, lightly sanded, and independently read three times to estimate age. The estimated ages were compared with known chronological age to assess the accuracy and precision of daily increment counts across rearing environments. Results Daily increment deposition was validated through 51 d posthatch for the tank-reared fish and through 69 d posthatch for the pond-reared fish. Beyond these ages, the estimated ages increasingly underestimated known age due to compression of daily increments near the otolith core and outer margin, particularly in slower growing individuals. Growth rates differed substantially between the two rearing environments and influenced increment spacing and readability. Otolith size was strongly correlated with the total length of the fish but decreased relative to chronological age as increment compression increased, particularly in fish exceeding approximately 40–50 mm total length (TL) in tank-reared and 60–70 mm TL in pond-reared individuals. Conclusions Lapilli otoliths provide reliable daily age estimates for Grass Carp during early life stages under both laboratory and pond conditions. These validated methods enable robust estimation of hatch timing and early growth, providing a foundational tool for studying early life history and informing control efforts for invasive Grass Carp populations
Abstract Despite being a direct measure of biomass and central to fisheries management, weight-based metrics remain underutilized in freshwater fish stock assessment. Here, we present a concise review of the application of weight in evaluating freshwater fish populations. We examine the historical use of weighing, assess how weight is applied across subdisciplines of freshwater fish science, contrast weight- and length-based approaches, and identify biases in their application. We then synthesize weight-based metrics, indices, and models within four broad categories—population and community weight structure; condition, growth, and efficiency; reproductive potential and production; and yield and exploitation dynamics—highlighting approaches that inform fish ecology, population and community dynamics, and vital rates. We conclude by identifying key opportunities and methodological innovations needed to expand the effective use of weight-based metrics in freshwater fish conservation and management.
Abstract Objective Catch and release of Muskellunge Esox masquinongy approaches 100% within Ohio waters. There is evidence that Muskellunge caught and released in Ohio reservoirs exhibit lower survival compared with nonangled fish. The factors influencing survival after catch and release remain uncertain. Recent studies from locations outside Ohio suggest that elevated water temperatures may reduce survival after catch and release of Muskellunge. Here we used mark–recapture data to evaluate the relationships between fish length and water temperature on future recaptures of Muskellunge angled at Leesville Lake, Ohio. Methods Muskellunge were collected and tagged each spring during 2016–2022 by the Ohio Department of Natural Resources, Division of Wildlife via netting at Leesville Lake. Anglers reported catches of tagged Muskellunge, and subsequent recaptures (angler and netting) of fish caught and released were monitored during 2016–2025. Using data for fish that were and were not recaptured after being angled and released, we modeled the relationship between fish length, water temperature, and the probability of recapture (a proxy for apparent survival) after being angled. The relationship between temperature and recapture was evaluated using a variety of metrics employed by previous studies: mean daily temperature, warmwater period of July–August, temperatures >25°C and >26.7°C, and 5-d cumulative water temperature. Results A total of 581 catch-and-release events, representing 482 tagged Muskellunge, were evaluated. Of these fish, 45.0% were recaptured during 2016–2025. Their probability of recapture was unrelated to fish length or any of the temperature metrics evaluated. Conclusions Our results were consistent with previous work for fish length, but other studies have found lower survival during elevated temperatures. The relationship with temperature may not be consistent across locations and regions. Further exploration into the factors influencing survival after catch and release of Muskellunge across regions and types of water bodies is warranted.
Abstract Objective Fluorochrome markers are often used for in vivo studies investigating increment formation in calcified structures of fish (e.g., otoliths, bones, or scales) because they are rapidly incorporated and form a visible time stamp in the structures. Oxytetracycline is the most common fluorochrome marker used in fisheries studies, but due to concerns about antibiotic resistance, its use has been discouraged or restricted. We evaluated safety and efficacy of intramuscular injection of two alternative fluorochrome markers, calcein and alizarin red S (ARS), for marking pectoral fin spines in age-1, hatchery-raised Atlantic Sturgeon Acipenser oxyrinchus. Methods We injected 20 age-1 Atlantic Sturgeon for each of three calcein and ARS dosage treatments. Growth and survival of experimental fish were compared with those of fish injected with 0.9% sterile saline (procedural control) and fish that were not injected with anything. Half of the fish received an injection in late May at a tank water temperature of 23°C, and half were given an injection in mid-July at a tank water temperature of 29.5°C to simulate water temperatures in southeastern rivers during the sampling period. Fish growth and survival were monitored until early October, when small sections of the pectoral fin spine were collected to evaluate marking efficacy. Contingency tables were used to compare survival across treatments, and ANOVA was used to compare growth (length and weight). Results Survival was high (>97%) across the study period and did not differ among treatments; only one mortality was observed for each of the chemical and saline treatments, and one mortality was observed in fish that did not receive an injection. Marking was 100% effective for fish injected with calcein and 98% effective for fish injected with ARS. Growth did not differ across treatments. Conclusions Calcein and ARS are safe and effective fluorochrome markers for use in juvenile Atlantic Sturgeon. Because we found effective marking at all treatment levels, we recommend a calcein dosage of 5 mg/kg or the use of our low-dosage protocol for ARS.
Objective Fisheries-dependent and fisheries-independent information is critical for assessing the status and trends of fish populations and regulations. We tested for changes in common fisheries-dependent and fisheries-independent metrics for Largemouth Bass Micropterus nigricans (LMB) and Smallmouth Bass M. dolomieu (SMB) in Wisconsin during 1990-2024. We also tested for responses associated with liberalized harvest regulations compared with a more conservative bass regulation.Methods We used creel survey data collected during 1990-2024 to test for trends in fisheries-dependent metrics. We used electrofishing data to test for trends in fisheries-independent metrics. Electrofishing data were also used to test for differences in relative abundance and proportional size distribution in a subset of bass populations with liberalized harvest regulations versus a more conservative black bass regulation.Results Directed angler effort for SMB significantly increased, whereas directed effort for LMB did not change. Catch rates for both species significantly increased. Harvest rates for LMB remained low, while SMB harvest rates significantly declined. Relative abundances for both species significantly increased. Population size structure increased for low to intermediate length-classes of LMB and intermediate to high length-classes of SMB. Density-dependent growth responses in mean length at age were evident in older age-classes for both species. Relative abundances of LMB populations with liberalized harvest regulations significantly declined, whereas SMB showed no change. Both species showed increased population size structure, but the increase was greater for LMB.Conclusions Our results suggest that bass populations are thriving in Wisconsin. However, density-dependent effects on growth may not be balancing diverse angler desires of catch and trophy potential or alleviating the negative correlation of LMB with Walleye Sander vitreus. Liberalized regulations on LMB showed promise for better balance in diverse bass fishing opportunity. Whether future angler behavioral responses (e.g., harvest rates) will be sufficient to balance fish communities that are managed for multiple species and ecosystem services is unclear. Black bass angler effort, catch rates, and relative abundances have increased over time in Wisconsin, with implications for growth, population size structure, and other species, such as Walleye. Liberalized harvest regulations showed some promise for reducing Largemouth Bass abundances.
Objective Tagging methods used to deploy biologging devices must balance retention, fish welfare, and data reliability, yet limited comparative work has evaluated attachment techniques for Channel Catfish Ictalurus punctatus. We aimed to compare conventional internal tag placement as unsecured tags within the peritoneal cavity to external attachment via anchor tags, which have higher retainment rates but have not been previously used for biologger attachment.Methods We assessed dummy tag retention performance in juvenile-adult (market-sized) Channel Catfish across five attachment methods: two internal implantation approaches (midline and lateral incisions) and three external methods (T-bar tags with tape, T-bar tags with zip-tie fixation, and dart tags). Fish were surgically tagged, allowed to recover, and monitored for 160 d for wound healing, survival, and tag expulsion.Results Wound healing was high for all treatments, suggesting that tag loss was not associated with poor healing at incision sites. Internal tags had similarly high retention rates between the two groups, with mean durations of 142 d for midline incisions and 139 d for lateral incisions. Fish had 75% and 89% retention by 140 d and 38% and 55% retention by 160 d for midline and lateral incision groups, respectively. External tags exhibited markedly lower retention rates, with mean durations of 41-82 d for T-bar attachments and only 10 d for dart tags. Fish with dart tags had 0% retention by day 16, while fish that received the T-bar with tape had 11% retention and those receiving the T-bar with zip-tie attachment had 50% retention at 105 d. Postexperiment necropsies revealed predictable internal tag expulsion pathways, including hepatic adhesion and transintestinal movement, which suggested that the tags would have been eventually expelled.Conclusions These results demonstrate that unfixed internal implantation can provide better retention and healing outcomes compared with external attachment methods. Our work extends previous findings that difficult-to-tag catfish can have higher retention for 140 d with placement through a lateral incision. We assessed five different tagging methods in catfish, which are known to readily expel tags. Internally placed tags had an average of 82% retention over 140 d. In contrast, external tags had 0-50% retention over 10-105 d. Post-experiment necropsies revealed that internal tags would have been eventually expelled.
Objective The King Mackerel Scomberomorus cavalla is a coastal pelagic marine teleost found in tropical and subtropical waters in the western North Atlantic Ocean, including the Gulf of Mexico and Caribbean Sea. The species is important for commercial and recreational fisheries in the southeastern United States, with two populations currently recognized for management purposes (Atlantic and gulf). King Mackerel are also hosts for a diverse parasite assemblage. The goal of this study was to assess any differences between the parasite component communities of these two populations and assess the potential use of parasites as biological tags.Methods A total of 168 specimens were donated from nine fishing tournaments in Florida, Alabama, and South Carolina, spanning both the Atlantic and gulf to reflect the current fisheries management plan. The sampling area was divided into four regions, based on the geographic distance from the mixing zone. Mean abundance and prevalence were calculated for each of the parasite taxa recovered, as well as parasite species richness at both the infracommunity and component community levels.Results A total of 22 parasite taxa were identified, 7 of which had not been previously described from this host species. Compositional differences were observed in the parasite component communities of King Mackerel from the Atlantic and gulf populations, as well as differences in relative abundance of several parasite taxa. Each of the four regions in this study showed significant differences in parasite community structure with each of the others. The average dissimilarity between each of the different regions ranged from 57% to 60%, with four taxa (Hysterothylacium sp., Brachyphallus parvus, Prosorhynchoides scomberomorus, and an unidentified taxon within the order Tetraphyllidia) driving the dissimilarity.Conclusions We found significant differences between the endoparasite communities of King Mackerel in the Atlantic and gulf. Multiple parasite taxa found in the Atlantic were not found in the gulf, but even among parasites found in both regions, there were still significant differences between the parasite community composition of the regions. The observed differences suggest that parasite relative abundance and community composition might be useful biological tags in this management unit. Parasites can be useful as biological tags for identifying fish stocks and tracking the movement of populations.
Objective People are exposed to mercury (Hg) through the consumption of fish. State and federal governments provide broad, often-generalized food safety guidance to reduce exposure; however, numerous rural fishing areas lack testing and location- or species-specific guidance. The aim of this study was to provide tangible, visible, or easily measured characteristics of Lake Trout Salvelinus namaycush that could convey information on Hg exposure to people harvesting and consuming fish where no location-specific guidance exists.Methods We investigated potential indicators of Lake Trout total Hg (THg) concentrations in muscle across 10 lakes in Alaska's national parks. Potential indicators, including lake, lake zone (i.e., littoral, pelagic, profundal), fish length, head size, body condition, and general appearance, were evaluated by competing linear mixed-effects models.Results Lake Trout THg concentrations ranged widely from 22 to 1,306 ng/g wet weight. Much of the variation (48%) in THg concentrations was attributed to differences among individual lakes, but the interaction of the fish's lake zone, body length, and head size accounted for an additional 21%. Predicted THg concentrations increased with Lake Trout length and head : body proportion, but the rate of THg concentration increase with length varied by head : body proportion and lake zone.Conclusions Given the overwhelming evidence of high lake-to-lake variability in Lake Trout THg concentrations, we find support for use of lake-specific guidance when data are available. When lake-specific THg concentrations are not available, the best potential way to reduce exposure is to harvest and consume Lake Trout with mean predicted THg concentrations that are within state and federal safe consumption guidelines. This included Lake Trout from surface waters (i.e., pelagic or littoral zone) that are <= 70 cm in length; if harvesting fish from deep waters (i.e., profundal zone), lower THg concentrations were found in Lake Trout with heads <= 25% of their body length. The indicators-lake zone, length, and head size-of Lake Trout THg concentrations can provide harvesters with additional information in the absence of data for specific lakes. Most mercury consumption guidelines for Lake Trout are not lake-specific. In the absence of guidance, lake zone, body length, and head size can provide information to harvesters. Reduce exposure by harvesting from surface waters any Lake Trout <= 70 cm (28 inches) or from deep water those with heads <= 25% of body length.
Objective The National Fish Hatchery System's role in supplementing declining fish populations is critical to achieve U.S. conservation objectives. However, hatchery-reared fish often exhibit lower fitness and survival compared with their wild counterparts. This difference is potentially due to environmental factors that are unique to hatchery environments. We sought to understand the relationship between hatchery-derived noise and early rearing habitat on the development, sensory physiology, swim performance, and survival of Chinook Salmon Oncorhynchus tshawytscha.Methods Before first feeding, juvenile Chinook Salmon were reared in two different rearing habitats (Heath trays and Redd Boxes). After feeding began, fry were transferred to enclosures with one of three noise conditions: quiet (noise abated), ambient hatchery noise, and continuous white noise treatment (150 dB [referenced to 1 mu Pa]). During each month (February-April), we analyzed growth metrics, brain-to-body-weight ratios, lateral line neuromast number, and inner ear cell counts. In April (prerelease), we also analyzed swimming performance and then tagged and released fish to quantify adult return rates.Results We observed moderate differences in fish length in April, shortly before fish were released. Neither sensory development nor swimming behavior was substantially impacted by rearing environment or noise exposure. However, we saw significant differences in return rates between noise treatment groups. We found that fry exposed to continuous white noise were significantly less likely to return to the hatchery, whereas fish in the quiet and ambient noise treatments had higher return rates.Conclusions Our findings indicate that chronic high-intensity noise exposure in hatcheries can negatively affect return rates of hatchery-reared Chinook Salmon, highlighting the importance of soundscape management to optimize fish fitness. High-intensity white noise caused minimal developmental changes in juvenile Chinook Salmon compared with usual hatchery noise levels. However, white noise impacted return rates to the hatchery. Raising fish in noise-abated enclosures may improve return rates in hatchery-reared Chinook Salmon.
Black bass Micropterus spp. populations, fisheries, and their management are at a crossroads, creating an opportune time to consider their current state and identify opportunities for working collectively towards a better future. Here I present six maxims (identified from my experiences and familiarity with the literature) for the responsible and sustainable management and conservation of black bass intended to benefit fish and people. Maxims are short statements expressing a general truth or fundamentally held principle and are also logically complemented by considering their implications (in the form of needs). The maxims identified are as follows: (1) Black bass have diverse socioeconomic and cultural value, (2) habitat is the foundation for healthy and productive black bass populations and fisheries, (3) black bass are sometimes good for biodiversity but are not always good for biodiversity, (4) the black bass management toolbox is antiquated, (5) black bass recreational fishing requires two licenses-one for fishing and a social license, and (6) black bass and bass fishing are for everyone. Implications of these maxims are wide-ranging, but all demand action to ensure that black bass are valued, that their habitat and populations are managed using robust evidence-informed practices, that their contribution to biodiversity is understood, that the social license for bass fishing and their management is maintained, and that black bass are managed for the benefit of all. Here I present six maxims for black bass management and conservation: (1) Black bass have diverse socioeconomic and cultural value, (2) habitat is the foundation for healthy and productive black bass populations and fisheries, (3) black bass are sometimes good for biodiversity but are not always good for biodiversity, (4) the black bass management toolbox is antiquated, (5) black bass recreational fishing requires two licences-one for fishing and a social licence, and (6) black bass and bass fishing are for everyone.
Objective Fisheries-dependent data (e.g., angler effort, catch, and harvest rates) are important for understanding angler behavior and can be useful for managing some aspects of recreational fisheries. However, the collection of fisheries-dependent data through traditional point-intercept angler creel surveys is expensive and labor-intensive. We evaluated model-based approaches to predict fisheries-dependent metrics, which may be more cost-effective for fisheries management agencies that are trying to balance the need for creel survey information and fisheries-independent population monitoring.Methods We used a Bayesian modeling approach to analyze 33 years of standardized point-intercept creel information from the recreational Walleye Sander vitreus fishery in northern Wisconsin to test whether reduced survey designs could still accurately predict catch, harvest, and exploitation rates. We strategically reduced the creel survey data set in five different ways (i.e., seasonal reductions, removal of survey days) to represent alternative survey designs with reduced creel clerk effort that may be more efficient.Results The analysis of 33 years of creel survey data pooled together generally found no difference between the estimates of fishery-dependent metrics from the current creel design and the five alternative creel designs using Bayesian P-values and root mean square error. An annual analysis of the same metrics also found no difference between the current creel design and the five reduced creel designs for most years (mean of 91.2% across metrics and scenarios). Of note, however, the seasonal reductions in creel effort, while not significantly different from the current creel design, did perform worse than the percentage reductions that were applied evenly across the year.Conclusions The five alternative creel survey designs reproduced key fishery-dependent metrics that were not different from the estimates obtained via the current creel survey design. This suggests that creel effort could be reduced without compromising the critical estimates that are needed for the Walleye management system in northern Wisconsin and allow for more lakes to be surveyed on an annual basis. Although there are few significant differences between reduced-sampling designs and the full design, there are differences in performance among the different reduced designs that should be considered if surveyors are choosing among the different reduced designs for implementation. The creel survey for the recreational Walleye fishery in northern Wisconsin is predicated on spending a lot of time at a few lakes to estimate angling metrics. Our analysis suggested that less time could be spent on each lake without compromising the estimates used for management. This may allow for more lakes to be surveyed annually.
Objective: We sought to quantify Largemouth Bass Micropterus nigricans diets in small impoundments and investigate how seasonal and ontogenetic factors interact across a gradient of Gizzard Shad Dorosoma cepedianum relative abundances to influence prey selection. Methods: We collected stomach contents from 3,500 Largemouth Bass across 12 small Kansas impoundments (<166 ha) during June, August, and October 2017 through 2020. We used generalized linear mixed-effects models to quantify the influence of Largemouth Bass size, season, and Gizzard Shad relative abundance on the frequency of coarse-scale (fish, crayfish, aquatic insects, and zooplankton) and fine-scale (Centrarchidae, Gizzard Shad) prey taxa in Largemouth Bass diets. Results: Gizzard Shad relative abundance significantly altered diet composition in addition to notable effects of season and Largemouth Bass size. Increasing Gizzard Shad abundance was associated with reduced consumption of alternative littoral prey (Lepomis spp. and crayfish) and increased aquatic insect consumption, particularly in individuals <150 mm. While consumption of Gizzard Shad increased with Gizzard Shad abundance, its occurrence in diets remained low (<10%) and was seasonally restricted to October. Conversely, consumption of Centrarchidae declined significantly as Gizzard Shad abundance increased. Conclusion: Despite their low occurrence in diets, Gizzard Shad appeared to alter food-web structure by disrupting consistent littoral energy pathways and diverting resources into a dynamic pelagic base that was largely unavailable to Largemouth Bass. The negative association between Gizzard Shad abundance and Centrarchid consumption suggests that small impoundments with high densities of Gizzard Shad may exhibit reduced trophic efficiency, as energy is sequestered in gape-protected Gizzard Shad biomass rather than being transferred to Largemouth Bass. Further research integrating growth and bioenergetic data is warranted to determine how energy is most successfully transferred to Largemouth Bass, specifically comparing net benefits of a transient autumn pulse of Gizzard Shad compared with a consistent supply of littoral forage.
Objective Understanding the origins and movements of fish is fundamental to effective conservation and fisheries management. Strontium isotope ratios (87Sr/86Sr) in otoliths provide a powerful tracer of natal origin and migratory pathways. However, existing 87Sr/86Sr isoscapes for the Sacramento River basin, an ecosystem that supports ecologically and economically important salmon populations, rely on discrete classification approaches that overlook unsampled habitats and do not incorporate spatial uncertainty. Our objective was to develop a continuous, network-explicit 87Sr/86Sr isoscape with quantified uncertainty to fill in data gaps and enable probabilistic assignments of fish origin and movement.Methods We used river water 87Sr/86Sr data from 106 sites (1997-2021) to develop spatial stream network models that use dendritic connectivity and watershed characteristics (lithology, bedrock age, and land cover) to predict river water 87Sr/86Sr throughout the basin. Models were fitted using maximum and restricted likelihood and were evaluated via Akaike's information criterion and leave-one-out cross validation. We produced both historical (pre-dam) and present-day (below-dam) isoscapes, delineated uncertainty-informed isotopic ranges using k-means clustering, and applied a proof-of-concept Bayesian assignment to estimate natal origins and early rearing habitats for two endangered winter-run Chinook Salmon Oncorhynchus tshawytscha.Results Cross validation indicated strong performance of the 87Sr/86Sr model (leave-one-out cross validation: R2 = 0.91; root mean square error = 0.0005). Uncertainty-informed clustering identified 19 isotopic "suites" (reaches with indistinguishable 87Sr/86Sr values) in present-day anadromous habitats and 25 suites in the historical network. Example natal and early rearing assignments included predictions that challenged expectations for juvenile salmon migration based on predicted river 87Sr/86Sr compositions.Conclusions This study developed a continuous, network-explicit 87Sr/86Sr isoscape that integrates existing river data to predict 87Sr/86Sr in unsampled reaches and the likely achievable range and resolution of otolith-based origin and life history inference. The resulting river isoscape provides a valuable tool to predict salmon movements and identify habitats supporting their survival and growth that otherwise might remain undetected. Coupling these predictions with complementary approaches that ground-truth juvenile presence (e.g., targeted fish surveys) represents an important step toward science-informed restoration and management of critical habitats throughout the Sacramento River basin. We developed a continuous strontium isoscape with uncertainties for the Sacramento River basin. Combined with Chinook Salmon otolith isotope analyses, it identifies natal and rearing tributaries missed by discrete approaches, which can guide restoration, reintroduction, and recovery efforts.
Objective The Ohio Department of Natural Resources-Division of Wildlife uses regulations on black bass Micropterus spp. populations to create diverse bass fishing opportunities. However, the growing adoption of catch and release among bass anglers has limited the ability of harvest regulations to meaningfully shape populations, meaning that such regulations may not be necessary. To inform potential regulation changes, we sought to understand the preferences of Ohio's bass anglers.Methods We conducted an online survey with a random sample of anglers who had an active 2024 Ohio fishing license. Anglers who indicated that they primarily targeted bass in the past 12 months (n = 814) were asked to report their demographics (gender and age), fishing behavior (days fished and tournament participation), harvest orientation, and angler specialization. These variables served as a basis for comparing regulation preferences.Results Ohio's bass anglers generally supported fishing regulations. Anglers opposed removing daily limits and size limits altogether, were neutral towards enacting stricter limits, and supported simplifying regulations. Some regulation preferences differed by harvest orientation and specialization, but support for simplifying regulations was consistent across angler types.Conclusions Ohio's bass anglers value fishing regulations even when the biological impact of such regulations is minimal. Therefore, removing bass regulations altogether would likely draw complaints, but simplifying Ohio's bass regulations may be an acceptable management decision for bass anglers. This study illustrates the importance of considering angler preferences for fishing regulations alongside the biological impacts. In response to an online survey, Ohio's black bass anglers said that they would support simpler fishing regulations. Anglers of all experience levels and preferences shared this support.
Objective Smallmouth Bass Micropterus dolomieu are frequently displaced during fishing tournaments that are held at centralized weigh-in locations, which may result in temporary stockpiling (i.e., concentration near the weigh-in location) and increased vulnerability to angling. It is unclear whether displaced individuals return to established home ranges. The objective of our study was to evaluate the effects of tournament displacement on Smallmouth Bass behavior in Dworshak Reservoir, Idaho, United States.Methods We implanted acoustic transmitters into 31 adult Smallmouth Bass during spring 2023, including 15 fish that were released at the site of capture and 16 individuals that were displaced to a popular tournament weigh-in location. Displacement distances ranged from 7.7 to 63.0 km. We assessed the duration of stockpiling, quantified the proportion of displaced fish that returned to established home ranges, characterized the timing and routes of return, and compared home range patterns between displaced and nondisplaced fish.Results Most (94%) of the displaced fish dispersed from the weigh-in location, with the majority doing so within 25 d. Ten displaced individuals returned to their original capture locations, including fish that were displaced up to 63.0 km. Six of the returning fish followed indirect routes rather than direct movement paths. Home range size and spatial use of displaced fish were similar to those of nondisplaced fish, indicating no detectable long-term behavioral effects of displacement.Conclusions Tournament-related displacement of Smallmouth Bass in Dworshak Reservoir did not result in prolonged stockpiling or long-term changes in home range behavior. Our findings suggest that additional restrictions on tournament displacement procedures are unnecessary in similar large-reservoir systems. Smallmouth Bass that were moved during simulated bass tournaments did not stay grouped near the release site for long and often returned to where they were caught, suggesting that these displacement events may have less long-term impact on fish behavior than is commonly assumed.
