Journal of the Southeastern Association of Fish and Wildlife Agencies

Fisheries

Lynn D. Wright, Timothy J. Bister

1     Examining Hybrid Striped Bass Stocking Rates in Texas Reservoirs: A Trade-off between Abundance and Stocking Efficiency

M. Todd Driscoll, Jacob D. Norman

7    High Mortality of Largemouth Bass Implanted with Transmitters at Colder Water Temperatures

Brent J. Bellinger, Marcos J. De Jesús

14   Hydrilla Management Impacts on a Largemouth Bass Fishery: A Case for a Balanced Management Approach

Daniel L. Bennett, M. Todd Driscoll, Jacob D. Norman

Hybrid striped bass (HSB), which includes palmetto bass (female striped bass Morone saxatilis × male white bass M. chrysops) or its reciprocal sunshine bass (female white bass × male striped bass) support popular fisheries in many Texas reservoirs. Data from 41 reservoirs sampled using gill nets from 1996–2021 (total of 255 reservoir-yr) were used to develop stock-recruit models where fingerling stocking rates were used to predict CPUE of adults in gill nets. Adult relative abundance was described using two size classes based on the statewide 458-mm minimum length limit, catch of fish below (CPUESUB) and above (CPUE458) the limit. A linear mixed-effect model showed stocking rate explained 41–46% of variation in CPUE estimates.  Mean stocking rate from 3–4 yr prior to each gill-net sample were best for predicting recruits for the CPUE458 size class, while stocking rate calculations from years 3–5 and 3–6 explained less variation.

Biotelemetry via surgical implantation of an electronic tag is a common way to examine fish behavior and movement. Previous studies suggest higher post-operative survival should be expected when implanting tags at colder water temperatures. However, during the initial part of our study, all 26 adult largemouth bass (Micropterus salmoides) we implanted with transmitters at water temperatures from 14 to 17 C at Toledo Bend Reservoir, Texas, died within 4 wk post-surgery. To further investigate this phenomenon, we conducted two tagging trials at 13 C, observing post-operative mortality of 100% (n = 5) and 58% (n = 12); all fish that died developed external fungal infections (i.e., saprolegniasis). Post-operative survival was 100% in a third trial at 24 C (n = 6) and no fungal infections were observed. Subsequently, tagging mortality was ≤ 20% when 81 largemouth bass were tagged at water temperatures from 22 to 30 C at Toledo Bend and Lake Fork reservoirs.

Lake Austin, in central Texas, supported a popular trophy largemouth bass (Micropterus salmoides) fishery concomitant with conservative hydrilla (Hydrilla verticillata) management during the period 2002–2011. However, a change from this conservative approach to an aggressive stocking rate of triploid grass carp (Ctenopharyngodon idella) in response to excessive hydrilla growth between 2011–2013 subsequently resulted in the eradication of all submerged aquatic vegetation (SAV). The loss of SAV quickly changed the angling dynamics of the reservoir, resulting in a controversial decline in the quality angling experience. The objectives of this case study were to compare how available population metrics of largemouth bass and important prey fish differed between periods of SAV presence (1997–2013) and absence (2014–2022) to inform which SAV management approach better supports a sustainable trophy fishery goal.

An economic valuation of the recreational sport fishery of Lake Fork in northeast Texas was completed in 2014 and 2015, finding that angler direct expenditures totaled US$18.8 million annually on fishing trips to the reservoir. Although some largemouth bass (Micropterus salmoides) tournament anglers were included in that study, it did not assess economic impacts of six large (>200 participants) tournaments during the study period. Since 2006, largemouth bass tournament effort at Lake Fork has generally increased to comprise half of all fishing activity in the reservoir and is currently believed to account for most of the Lake Fork sport fishery’s economic value. This is despite supporting a renowned trophy fishery for largemouth bass managed by a highly restrictive slot-length limit that makes it difficult to conduct tournaments using traditional formats.

Accurate age estimates are critical in the development, implementation, and assessment of silver carp (Hypophthalmichthys molitrix) management plans. Lapilli otoliths are the most commonly used calcified structures for silver carp age estimation, but studies on the precision of two established preparation methods [i.e., grind-and-burn (GB), thin-section (TS)] are lacking. Therefore, we assessed within-reader, between-reader, and between-method precision for 125 silver carp collected from six rivers throughout the Lower Mississippi River Basin (Arkansas, Cache, Mississippi, St. Francis, White, and Yazoo). Additionally, we compared the effort and material costs associated with each method. Overall, younger ages were estimated with the GB method (median estimated age = 6 yr, range = 3–12) than the TS method (median estimated age = 7 yr, range = 3–13).

Non-native species have sometimes been introduced to increase forage availability and sportfish production, but such introductions have potential for negative as well as positive effects. In 2010, non-native blueback herring (Alosa aestivalis) were found in Lewis Smith Lake, Alabama, due to illegal stocking. Our objective was to quantify food habits and determine potential impacts of blueback herring introduction on body condition and growth of important sportfishes in Lewis Smith Lake. Largemouth bass (Micropterus salmoides), Alabama bass (Micropterus henshalli), and striped bass (Morone saxatilis) were sampled in 2013 and 2014, and diets of these post-blueback herring introduction piscivores were quantified.

Monitoring changes in occupancy (i.e., probability a site has at least one individual of a species) across time is considered an inexpensive alternative to monitoring changes in abundance and can be used to monitor multiple species simultaneously across a watershed. Occupancy can be measured as the proportion of sites where a species is detected during surveys (i.e., naïve occupancy), but is more commonly modeled by surveying sites multiple times to estimate detection probability and address false-positive survey errors (sites that are occupied but with no survey detections of the species). This results in an unbiased estimate of occupancy, but at the expense of more effort. The purpose of this study was to determine management implications of using naïve occupancy versus using modeled occupancy. We generated simulated data to represent monitoring a population, then compared performance of using naïve occupancy vs. modeled occupancy for detecting changes.

Across the U.S., the presence of white-tailed deer (deer; Odocoileus virginianus) in urban areas can create conflicts with residents (e.g., ornamental plant damage). State wildlife agencies approach urban deer management differently from traditional deer management due to diverse community groups, urban stakeholder viewpoints about deer, and other aspects of wildlife management in urban environments. With this variation in mind, we reviewed deer management resources across the U.S. to understand the current state of urban deer management. Of the 46 states with deer populations, 21 had publicly available deer management plans (DMPs; 46%), 22 had only online urban deer management resources available (48%), and three had no urban deer-related information available even though deer were present (7%). Our synthesis revealed that public input was incorporated in all DMPs including input from traditionally under-represented stakeholders.

Wildlife management agencies in regions where chronic wasting disease (CWD) is prevalent have adopted costly management practices to mitigate the spread of this fatal and highly transmissible disease. Non-market valuation represents a critical tool for managers attempting to address these costs, but the mode and methods of contingent valuation (CV) questions can impact valuations due to biases inherent to self-reporting economic decisions. We administered online (n = 1430) and phone (n = 602) surveys in North Carolina and South Carolina to assess what hunters with licenses to hunt white-tailed deer (Odocoileus virginianus) were willing to pay for CWD testing and carcass disposal across survey modes and CV methods. Among the online survey respondents, 34.1% (n = 488) were willing to pay for testing and 43.4% (n = 620) were willing to pay for disposal. From our phone sample, 48.6% (n = 293) were willing to pay for testing and 50.7% (n = 306) for disposal.

Plantings of perennial and biennial forage, such as white clover (Trifolium repens), red clover (Trifolium pratense), and alfalfa (Medicago sativa), commonly are used by managers to increase nutritional resource availability for white-tailed deer (Odocoileus virginianus). Regular mowing and selective herbicide applications are two common practices used to maintain perennial plantings and reduce weed competition. However, there is little information available on how these management activities influence perennial forages or wildlife response. We evaluated the effects of regular mowing on forage production, forage quality, weed coverage, and deer detections as a case study in a perennial forage planting in Tennessee, May–August 2020. We also evaluated deer detections following application of selective herbicides among four fields in Tennessee and North Carolina, October–November 2021.

Many states throughout the range of wild turkeys (Meleagris gallopavo) have delayed their spring wild turkey hunting seasons to allow reproductively active males more time to breed before being harvested and to potentially increase population fecundity rates. Six states in the Southeast recently delayed their spring hunting season by 7 to 14 days. However, there are no published data indicating their previous season frameworks had a deleterious effect on wild turkey reproduction or that delaying the season increased fecundity. In addition to potentially affecting turkey reproduction, changing the season framework may impact hunter behavior (effort and efficiency), success, and satisfaction. Our objective was to see how hunter ef- fort, success, efficiency, and satisfaction changed upon implementing a two-week season delay and a two-week reduction in season length to the spring wild turkey hunting season in south-middle Tennessee.

Understanding hunter satisfaction and behavior under normal and abnormal situations is important for effective management of game species by state wildlife agencies. SARS-CoV-2 (COVID-19) created a global pandemic that coincided with the 2020 spring wild turkey hunting season. Concern was expressed by some wild turkey researchers and biologists that COVID-19 lockdown protocols could result in increased hunting effort and unsustainable harvests because of people having more free time. We assessed how COVID-19 and associated lockdown protocols affected hunter satisfaction and behavior during the spring 2020 wild turkey hunting season by using responses from 2,000 annual surveys of wild turkey hunters (2017–2020) among five focal counties (Bedford, Giles, Lawrence, Maury, and Wayne) in south-central Tennessee.

Nest site selection has a critical effect on nest success for eastern wild turkeys (Meleagris gallopavo silvestris), yet the underlying drivers of nest site selection are often misrepresented in the literature. Early works typically focused on evaluating behavioral ecology of female wild turkeys before nest initiation, under the assumption that female wild turkeys sought out nest sites well in advance of nest initiation. However, recent work has clearly found no evidence of nest site search behavior before the day of nest initiation, thus increasing the need to focus evaluations of resource selection on the day when nest site selection occurs (i.e., the first day of laying). Our objective was to determine if differential selection for landcover characteristics was occurring on the first day of an egg was laid (e.g., date of nest site selection).

The lesser prairie-chicken (Tympanuchus pallidicinctus) has declined precipitously in abundance and currently occupies a substantially reduced portion of its historic range. Within the sand shinnery oak (Quercus havardii) prairies at the southwestern extent of the lesser prairie-chicken’s contemporary range, efforts to conserve the species have been constrained by limited information on how land management practices influence habitat quality, and subsequently, affect lesser prairie-chicken recruitment. From 2008–2011, we captured and radio-tagged hen lesser prairie-chickens to monitor broods during four breeding seasons in western Texas. We evaluated influences of vegetation structure and composition, insect availability, and weather on brood ecology on private lands with continuous cattle grazing but no recent herbicide treatment to control shrubs. We located 32 nests from 50 hens captured.

Land managers in the southeastern United States cultivate rice (Oryza sativa) to provide calorie-dense forage for autumn-migrating and wintering waterfowl and other migratory birds. Conservation planners require accurate yield estimates for rice and other energy-rich croplands to parameterize bioenergetic models and support data-driven, adaptive resource management efforts. We developed a rapid method to efficiently estimate rice yield and quantified associated precision, accuracy, sampling time, and operating costs in the Lower Mississippi Alluvial Valley (n = 16 fields). We compared a visual index of seed-head size and density using ocular scores (1–10; i.e., rapid assessment) to 1-m2 harvested plots within each field. We regressed our visual index against known rice yield estimates (kg [dry] ha–1) and related our yield estimates to rice cultivation practices to inform management actions that maximize yield and cost efficiency for wildlife management.

Monitoring waterfowl populations provides the basis for improving habitat quantity and quality, establishing harvest regulations, and ensuring sustainable waterfowl populations through appropriate management. Waterfowl biologists currently use a variety of population and habitat monitoring methods ranging from informal ground observations to low-level occupied aircraft surveys. Unoccupied aerial systems (UAS) may provide safer and more precise alternatives to traditional aerial survey techniques that are less disturbing to waterfowl, but there is limited information on how waterfowl in winter respond to UAS. Therefore, we compared the behavioral responses of waterfowl to helicopters and UAS on Missouri Department of Conservation

Wild pigs (Sus scrofa) are a highly destructive invasive species and reported to be present in 77% of counties in the southeastern U.S. Wild pigs may negatively affect white-tailed deer (Odocoileus virginianus; hereinafter, deer) and eastern wild turkeys (Meleagris gallopavo silvestris; hereinafter, turkey) via competition over forage or exclusion from preferred areas. To explore effects of wild pigs on spatial distribution of these species within a mixed agriculture-forest landscape, we developed models predicting camera trap detections of deer and turkeys as a function of landcover, calendar season, and wild pig presence. We deployed 147 passive camera traps and collected data for one month during each calendar season during 2020 to 2022 in southwestern Georgia (32,760 camera nights).

Management of wild pigs (Sus scrofa) typically employs some form of population survey methodology, and trail cameras are the most common tool for conducting these surveys. Identification of individual sounders is generally at the foundation of these population surveys. Pelage characteristics and relative age distribution of individuals within the sounder coupled with total sounder size are common characteristics used to identify unique sounders. However, in many populations, the pelage of many wild pigs is either black or wild/grizzled, making pelage characteristics unreliable for sounder identification. Consequently, our objective was to assess the potential of using sounder size and composition as a simple proxy for identification of individual sounders visiting a camera station. Specifically, we aimed to determine the probabilities of encountering two sounders of a specific size and composition at the same camera site.

Animal body mass can be used to estimate age, determine health status, or guide dosage when administering sedatives. Because it can be difficult to weigh live large animals, using morphometric measurements to estimate body mass is sometimes used in field studies. Several statistical models exist for estimating domestic pig mass from morphometric measurements, but models based on domestic animals are likely unreliable estimators of wild pig (Sus scrofa) body mass due to known hybridization between domestic and wild pigs, and variable environmental conditions. The goal of this project was to evaluate several easily obtainable morphometric measurements as predictors of wild pig body mass and compare our estimates with those of models developed from both wild and domestic pigs. We measured neck girth, heart girth, body length, and body mass from 127 wild pigs in Florida and Georgia, and 450 wild pigs in South Carolina.

Grain-based attractants (e.g., corn) are standard among most wild pig (Sus scrofa) trapping and non-invasive sampling efforts (e.g., genetic spatial capture/recapture, camera trapping), but their use is not always feasible due to cost, deployment restrictions (e.g., difficulty of transporting grain into remote areas, property rules), and potential disease concerns associated with concentrating non-target species at bait sites. Attractant deployment and efficacy should be considered by biologists, private landowners, and researchers given the ultimate need to use attractants to attract wild pigs. To examine the efficacy of potential non-grain attractants, we used remote camera grids to identify attractant(s) that maximized wild pig visitation while minimizing non-target species visitation in a forested landscape in the southeastern United States.

Wild pigs (Sus scrofa) are arguably one of the greatest wildlife management challenges facing natural resource professionals and landowners in the U.S., and lethal removal by trapping is often the most cost- and time-effective means for managing populations. Whereas numerous studies have examined the effects of trap type, trap activation designs, and baits on trapping effectiveness, no studies utilizing a conditioning period and accounting for unique individuals/sounders and wild pig social structure have examined the effects of trap door width on wild pig entrance into corral-style traps. Modifying trap door width may impact wild pig entrance rates into corral-style traps with wider doors better facilitating entrance. Our objective was to examine wild pig entry times into standard three-panel corral traps with wooden guillotine trap doors of either 0.8-m or 1.2-m widths.

The U.S. Fish and Wildlife Service allows acoustical surveys and automated identification software to determine the presence of the endangered northern long-eared bat (Myotis septentrionalis) and Indiana bat (Myotis sodalis). Analytical software is required to assess presence probability on a site-night basis using a maximum likelihood estimator (MLE) that accounts for interspecific bat misclassification rates. The current standard for occupancy is a returned MLE P-value < 0.05 at the nightly level irrespective of the number of files identified as either northern long-eared bats or Indiana bats. These MLE P-values can vary based on presence of other bat species with similar calls and the relative proportions of all species recorded. Accordingly, there is concern that with few nightly northern long-eared bat or Indiana bat recordings or the presence of large numbers of high-frequency bats, false-negative findings from a swamping effect could result.

Conservation of bats declining from white-nose syndrome (WNS) impacts requires an understanding of both temporal and landscape-level habitat relationships. Traditionally, much of the research on bat ecology has focused on behavior of summer maternity colonies within species’ distribution cores, including that of the endangered northern long-eared bat (Myotis septentrionalis). To further our knowledge of this species, we evaluated multi-season activity patterns in eastern North Carolina and Virginia, including areas where populations were recently discovered. We used passive acoustic monitoring to assess relative and probable activity of northern long-eared bats from October 2016 to August 2021. Northern long-eared bat relative activity was greatest in areas containing greater proportions of woody wetlands and upland pine-dominated evergreen forests.

Understanding the relationships of biotic and abiotic factors to seasonal activity at hibernacula is important for the conservation of bats impacted by white-nose syndrome (WNS). Research on the relative and probable activity patterns of the federally endangered northern long-eared bat (Myotis septentrionalis) primarily has focused on summer maternity colonies, whereas surveys at hibernacula have traditionally relied on external capture and internal counts. We used passive acoustic monitoring to assess the relative and probable activity of northern long-eared bats at 13 hibernacula in western Virginia, from August 2020 to May 2022. Northern long-eared bats were most active near hibernacula during warmer weeks of the fall swarm and spring emergence, when rainfall was low. Similarly, the probability of northern long-eared bat activity was highest near hibernacula during the spring/summer season.