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Management of Blue Catfish Ictalurus furcatus and Channel Catfish I. punctatus for trophy production has recently become more common. Typically, trophy management is attempted with length-based regulations that allow for the moderate harvest of small fish but restrict the harvest of larger fish. However, the specific regulations used vary considerably across populations, and no modeling efforts have evaluated their effectiveness. We used simulation modeling to compare total yield, trophy biomass (Btrophy), and sustainability (spawning potential ratio [SPR] > 0.30) of Blue Catfish and Channel Catfish populations under three scenarios: (1) current regulation (typically a length-based trophy regulation), (2) the best-performing minimum length regulation (MLRbest), and (3) the best-performing length-based trophy catfish regulation (LTRbest; “best performing” was defined as the regulation that maximized yield, Btrophy, and sustainability). The Btrophy produced did not differ among the three scenarios. ...

Aquatic vegetation can impact juvenile fishes through multiple pathways. Previous studies have found that dense macrophytes can cause a trade-off of survival for Bluegills Lepomis macrochirus, with decreased foraging efficiency in macrophytes but also decreased predation risk. For juvenile Largemouth Bass Micropterus salmoides, this phenomenon has been proposed but never experimentally tested. In addition, little information exists on the effects of vegetation on juvenile Largemouth Bass prior to the shift to piscivory, a critical period in the recruitment process. Therefore, the objective of this study was to determine if aquatic vegetation reduces the foraging ability of invertivorous (prepiscivorous) juvenile Largemouth Bass. Twenty-four invertivorous juvenile Largemouth Bass were tested individually at each of five stem densities (0, 125, 250, 500, and 1,000 stems/m2) of artificial macrophytes within 20.8-liter aquaria. Five treatments of a simple stem architecture (at all stem densities) and ...

Gill nets are inherently size selective, but selectivity curves can correct this bias. We sampled eight reservoirs with the North American standard gill net to develop a large length-specific data set for six species: Channel Catfish Ictalurus punctatus, hybrid Striped Bass (White Bass Morone chrysops × Striped Bass M. saxatilis), saugeye (Sauger Sander canadensis × Walleye S. vitreus), Walleye, White Bass, and White Crappie Pomoxis annularis. We then used the SELECT (share each lengthclass’s catch total) method to find the best-fit selectivity model to adjust the gill-net catch for contact selectivity. To determine the magnitude of these selectivity corrections, we compared adjusted and unadjusted length frequencies and size indices for each species at each reservoir. The bimodal model was the best fit selectivity model for all species. When selectivity-adjusted length-frequency data were compared with the original data, one-third of hybrid Striped Bass length frequencies and two-thirds of White ...

Previous laboratory studies have demonstrated that turbidity alters prey selection by Largemouth Bass Micropterus salmoides, but this has not been tested in the field. Laboratory studies have also suggested that daily rates of consumption by Largemouth Bass may decline as turbidity increases and that the rate of decline may differ among prey types, possibly providing a mechanism that drives the observed prey selection patterns. We conducted laboratory trials to measure daily consumption rates for Largemouth Bass when foraging on Bluegills Lepomis macrochirus and Gizzard Shad Dorosoma cepedianum; we also collected field data in three reservoir systems (Boomer, Sooner, and Guthrie lakes, Oklahoma) during 2 years to evaluate Largemouth Bass prey selection and consumption rates over a range of turbidity levels. In the laboratory trials, Largemouth Bass daily consumption rates declined with increased turbidity, but the decline was similar between the two prey types. We detected no correlations between ...

Broad-scale niche models are good for examining the potential for invasive species occurrences, but can fall short in providing managers with site-specific locations for monitoring. Using Oklahoma as an example, where invasive bighead carp (Hypophthalmichthys nobilis) are established in certain reservoirs, but predicted to be widely distributed based on broad-scale niche models, we cast bighead carp reproductive ecology in a site-specific geospatial framework to determine their potential establishment in additional reservoirs. Because bighead carp require large, long free-flowing rivers with suitable hydrology for reproduction but can persist in reservoirs, we considered reservoir tributaries with mean annual daily discharge ≥8.5 cubic meters per second (m 3 /s) and quantified the length of their unimpeded portions. In contrast to published broad-scale niche models that identified nearly the entire state as susceptible to invasion, our site-specific models showed that few reservoirs in Oklahoma (N = 9) were suitable for bighead carp establishment. Moreover, this method was rapid and identified sites that could be prioritized for increased study or scrutiny. Our results highlight the importance of considering the environmental characteristics of individual sites, which is often the level at which management efforts are implemented when assessing susceptibility to invasion.

Growing interest in catfish angling, particularly for trophy-sized fish, has resulted in new regulations that limit the harvest of large Blue Catfish Ictalurus furcatus in several states. For these regulations to be effective, released fish must survive to further contribute to the fishery, either through reproduction or subsequent recapture. We investigated the effect of capture depth, hook type, water temperature, and fish size on the delayed hooking mortality of Blue Catfish caught on juglines. Blue Catfish (N = 559) were caught from three Oklahoma reservoirs with either 5/0 circle hooks or J-hooks fished for 24-h sets. One experimental fish (captured via jugline) and one control fish (captured via low-frequency electrofishing) were then placed in field enclosures (N = 25) and monitored for mortality after 72 h. Mean mortality was low at 8.50% (range, 0.00–37.50%; SE, 1.81%). Mortality decreased significantly with decreasing water temperatures (P < 0.01; odds ratio 1.1). Mortality was highest ...

This paper illustrates the use of discrete-choice analysis, a nonmarket valuation technique, for assessing the effect of different management or fishing site quality variables on demand for urban fisheries. The study was carried out in three fishing ponds that are a part of the Close-to-Home Fishing Program in the Oklahoma City metropolitan area. We found that, on average, anglers were willing to pay more for physical infrastructure improvements, such as flush toilets ($3.81/year) and docks ($1.28/year), than for having larger channel catfish Ictalurus punctatus stocked ($0.23/year for a 4-in increase). Willingness to pay for improvements to the ponds was less for minority anglers than for other anglers. Having relative values for potential management changes for a fishery helps to inform fisheries managers about what characteristics are valued most by anglers, allowing managers to better serve the anglers' interest and to justify the costs of implementing these changes.

Current sampling methods for blue catfish Ictalurus furcatus are suspected of being strongly biased against preferred-length fish (≥762 mm in total length [TL]), making it difficult to accurately determine the species' population density and size structure. To understand this potential bias with respect to electrofishing, we conducted seasonal and habitat-specific sampling on three Oklahoma reservoirs using 15-pulse/s DC at the 100–1,000 V setting (the percent of range being adjusted to achieve 4-A output). Temperature, habitat, and reservoir section were analyzed to determine which variables were associated with the highest total catch per unit effort (CPUETotal), the CPUE of preferred-length blue catfish (CPUE762), and the relative stock density of preferred-length fish (RSD762). Total CPUE and CPUE762 were significantly higher when the water temperature was 18°C or more, but the variability increased as the temperature exceeded 28°C. Catch rates were significantly higher in the upper reservoir...

Understanding sampling effectiveness is critical to gear selection and the determination of larval fish dynamics. We evaluated bow-mounted push nets for collecting larval fish across reservoirs and habitats and compared them with traditional tow nets. By means of a pushed 0.5-m-diameter conical net and towed 0.5-m-diameter and 0.75-m-diameter conical nets, ichthyoplankton samples were taken during daylight hours from May to July on 21 reservoirs that varied in morphological and environmental characteristics. The push net had higher catches than the same-diameter tow net. However, the push net was not as efficient as the larger-sized tow net in July, when larvae are larger. For pelagic habitats, bow-mounted push nets or large tow nets will sample the larval fish community more efficiently than traditional 0.5-m-diameter conical tow nets. We also assessed push nets for sampling nearshore littoral habitats (

Trap nets of varying design are commonly used to assess fish populations, but the effect of the design on gear selectivity is not well known. In particular, it may be advantageous to use multiple net designs with different mesh and throat sizes to maximize the catch of specific length-classes and to minimize the risk of predation on small fish by larger fish. We compared the species composition, catch rate, and length distribution of fishes caught by three trap net designs with dimensions differing only in mesh size and throat size (0.6-cm delta mesh and 3.8-cm × 3.8-cm square throats, 1.3-cm square mesh and 7.6-cm × 7.6-cm square throats, or 2.5-cm square mesh and 12.7-cm × 12.7-cm square throats). A total of 3,473 fish of 18 species were captured from Sandy Lake, Portage County, Ohio, during 24 sample dates from June to August 1999. The large net design had a significantly higher average number of species captured (mean = 11) than the medium or small net design (means = 9 and 8, respectively). ...