Journal of the Southeastern Association of Fish and Wildlife Agencies

A winter drawdown was evaluated to control waterhyacinth (Eichhornia crassipes) in B. A. Steinhagen Reservoir in southeast Texas. A 1.8-m drop in water level was initiated on 15 December 1993 and maintained through 17 February 1994. Freezing temperatures were recorded on 19 days during the drawdown with the lowest temperature —6.7 C. A significant (P < 0.0001) reduction in waterhyacinth frequency of occurrence was indicated in line transects. Waterhyacinth areal coverage was reduced from 1,476 ha in June 1993 to 26 ha in June 1994.

The existence of a distinct walleye (Stizostedion vitreum) population in south-flowing drainages of the southeastern United States has been suspected for some time. Recently, a mitochondrial-DNA (mtDNA) marker was identified that permitted discrimination of these southern walleyes from northern forms. In order to determine the type and distribution of walleyes in Alabama, mtDNA analysis was conducted on 35 individuals collected from 3 river systems within the state. Thirty-one fish collected in the Mobile Basin were the southern form of walleye, which previously had been identified only in northeastern Mississippi, while 4 fish from the Tennessee River were of the northern form. There was no evidence for the successful establishment of any female walleyes from Ohio that were stocked into 2 impoundments in the Mobile Basin 10-20 years ago.

Genetically-marked strains of walleye (Stizostedion vitreum vitreuni) from Arkansas (ARS) and Iowa (IAS) were stocked simultaneously into a Texas reservoir in 1985 to evaluate strain-related performance differences associated with spawning and growth. Post-stocking collections made during the spring spawning season (1988-1990) resulted in the capture of 132 walleyes from this year class. ARS walleyes comprised 35% of 1985 year-class samples which was significantly higher than the stocking proportion (26%). Differences were attributed to ARS females being more abundant than IAS females in samples. This unexpectedly high abundance of ARS walleye was not considered an indication of higher survival but merely evidence of temporal differences in movement of females of each strain to spawning grounds. This hypothesis was supported by strain-related sex ratio differences identified in samples; ARS ratios favored females whereas IAS ratios favored males.

Fish biomass and angler harvest data were collected from Keowee Reservoir during a period when thermal characteristics of this reservoir were significantly altered by operation of a large steam-electric power plant. Plant operation increased the heat load of the reservoir and depressed the depth of the thermocline. During the 22-year sampling period, fish biomass (primarily for nonsportfish taxa) declined, fishing effort increased, and angler harvest rates remained unchanged.

Fish standing crop data from rotenone surveys of 43 Louisiana lakes from 1969 to 1989 were analyzed in an effort to classify them for fisheries management purposes. Total fish, largemouth bass (Micropterus salmoides), and >30-cm largemouth bass standing crops averaged 207.7, 11.8, and 7.7 kg/ha, respectively. Results from these rotenone surveys were compared to those of similar studies in the 1950s when Louisiana lakes were placed into habitat categories. Standing crops were compared to various water-quality parameters; they were positively correlated to chlorophyll-a levels. Standing crops of fish were affected by the location of the lake within land resource areas in Louisiana. Higher fish biomass occurred more often in lakes associated with the fertile soils of the Southern Mississippi Valley Alluvium than with the Southern Coastal Plain region of the state.

Fish habitat of the Edisto River Basin in South Carolina was evaluated using a geographic information system (GIS). A committee of fisheries biologists was formed to evaluate fish habitat within the Basin, and the GIS was used to compile and analyze data and generate maps to represent quality of fish habitat. United States Geological Survey (USGS) 1:24,000-scale digital line graph (DLG) hydrography data were assigned values for data on species composition, predesignated protected areas, riparian habitat, dams and impoundments, ditches and channelization, and water quality. Criteria were developed to evaluate fish habitat in the Basin. Each criteria was assigned a point value, and these values were totaled and subdivided into Value Classes 1, 2, and 3 representing high, moderate, and low quality fish habitat, respectively. Value Class 1 consisted of 92% of the main river reaches and the entire estuarine portion of the Basin.

Scales and otoliths from largemouth bass (Micropterus salmoides) of known ages (age 6, 7, and 8) were prepared and examined by 3 experienced readers who were uninformed of specimen age or length. Results indicated limited agreement between readers and numerous inaccurate age estimations. Among 97 scale samples read, all 3 readers only agreed on the age of a single specimen which was older than estimated; using otoliths, readers agreed on 4 specimens which were correctly aged. Percentage of correctly-aged fish ranged from 10% to 30% with scales and 39% to 47% with otoliths. Percent of fish correctly aged ± 1 year ranged from 29% to 77% with scales and 78% to 98% with otoliths. Backcalculated lengths-at-age based on scale annulus measurements made by a fourth reader who knew specimen age, length, and sex were typically less than actual measurements taken each year (in October) with the greatest differences for earlier years of life.

Age, growth and mortality of lane snapper {Lutjanus synagris) from the northern Gulf of Mexico (Port Aransas, Texas, to Panama City, Fla.) were examined. Otolith sections from 694 fish collected from January 1991 to December 1994 were used to develop growth information using 2 methods (direct proportion and regression) of back-calculation. Fish ranged in age from 2 to 17 years and their size ranged from 210 to 673 mm total length. Males grew slightly faster and were larger at age than females; however, the oldest (age 17 at 500 mm) and largest (673 mm at age 11) were females. Full recruitment to the recreational fishery was at age 4-5. Estimated instantaneous total mortality (Z) ranged from 0.3750 to 0.5767. Natural mortality (M) ranged from 0.1125 to 0.2388.

A total of 139 grass carp (Ctenopharyngodon idella) of unknown ploidy were collected by bowfishing during 1993 and 1994 in Lake Guntersville, Alabama. Ages were determined from sectioned otoliths (lapilli), then age-specific total lengths were back-calculated using scales of known age. Mean back-calculated total lengths of grass carp were 334, 627, 768, 852, 896, 895, 920, 965, and 973 mm at ages 1 through 9, respectively. A length-to-weight relationship was calculated as: weight (g) = 0.00000519 x total length mm3-14, r2 = 0.92. A von Bertalanffy growth equation described growth as: Lt = 954 (i-e-0.590(t-0.257)), r2 = 0.99. Growth averaged 2.33 kg/year through age 4; subsequent growth was much slower, averaging 0.71 kg/year. Growth in Lake Guntersville was slower and more variable than in the Santee Cooper reservoirs, South Carolina. Occurrence of 3 age classes not stocked by Tennessee Valley Authority (TVA) precluded mortality estimates.

The performance of 3 seines was evaluated in 6 state-owned public fishing lakes in Alabama. The catch of bluegill fry (Lepomis macrochirus) and young of year (YOY) largemouth bass (Micropterus salmoides) in a 4.6-m (short) seine and an experimental 9.1-m (medium) seine was compared. The catch of intermediate bluegills (8-13 cm TL) in the medium seine was subsequently compared to their catch in a 15.2-m (long) seine. The medium seine was similar to the short seine for collecting bluegill fry. The medium seine generally required fewer hauls but more work to achieve the same level of precision when collecting YOY bass. The long seine was more effective at collecting intermediate bluegills than the medium seine. The experimental medium seine would provide no advantage over the short and long seines if used to conduct routine balance checks.

We investigated effects of selected physical factors on the catch rate of white crappie (Pomoxis annularis) in trap nets in Mississippi lakes. Population data were collected on 7,782 white crappie from 557 trap-net samples in the fall (N = 4,679 fish/243 nets) and spring (N = 3,103 fish/314 nets), 1987-1989. Generally, catch/day (N fish/24 hours) estimates were higher and less variable in trap nets set at water depths of 1.0-2.9 m and on bottom slopes of 0.0%-7.9%. Catch/day estimates were higher, but equally variable, in trap nets set perpendicular to the shoreline and at water temperatures of 16.0-19.9 C in the fall and 20.0-23.9 C in the spring. These findings indicate trap-netting efficacy could be augmented by sampling under the specified ranges of sampling conditions.

An intensive hoop net study was conducted on the St. Johns River, Florida, to: (1) estimate commercial hoop net effort, bycatch and initial gamefish mortality; (2) determine delayed mortality of game fish caught in hoop nets; and (3) estimate riverwide gamefish mortality in hoop nets. A survey of all known hoop net fishers revealed 38 fished 2,386 hoop nets for 794,300 net-days of effort in 1993. Between July 1992 and June 1993, 1,053 commercially-fished hoop nets were observed that were fished 7,320 net-days. Catfish (Ictaluridae) comprised 95% of the 87,278 individuals captured, while game fish comprised 2.3% of the total catch. Estimated riverwide hoop net-induced mortality in 1993 was 1 black crappie (Pomoxis nigromaculatus)l9.1 ha and 1 Lepomis spp./10.5 ha. We felt these low mortality estimates did not threaten gamefish populations on the St. Johns River, and recommended allowing the continued use of hoop nets.

Tag retention and tag-induced mortality were evaluated for 2 sizes of Hallprint® dart tags injected in largemouth bass (Micropterus salmoides). Mean tag retention rates of 98% for larger (81 mm) PDB dart tags and 78% for smaller (69 mm) PDT dart tags were observed during a 15-month study in Lake Blanchester, Florida. Significantly higher tag loss (P ≤ 0.05) of PDT tags was attributed to a more flexible and shorter (12-mm) barb (anchor) compared to the larger and longer (18-mm) barb on the PDB tag. Estimated tag-induced mortality was 13% for bass 260-299 mm using smaller tags, and 18% for bass ≥300 mm TL using larger tags, over a 3-month period in a hatchery pond. However, there were no significant differences (P > 0.05) in mortality rates between control and tagged fish for 3 size groups. The larger tags with 98% tag retention and no significant tag-induced mortality are recommended for long-term tagging studies in bass ≥300 mm.

We tested the performance of low- (40 MHz) and high-frequency (150 MHz) radio and ultrasonic (75 kHz) telemetry transmitters in Robert S. Kerr Reservoir, Oklahoma, a polyhaline body of water. We measured the maximum detection distance of all 3 transmitters at various depths and conductivity levels in lacustrine habitats and the ultrasonic transmitter in riverine habitats. The ultrasonic transmitter had the greatest detection distance (600-1,200 m) in all lacustrine habitats and in clear, deep riverine habitats. Ultrasonic transmitter detection distance decreased by 94% at a shallow riverine site with high velocity and suspended sediment levels compared with a moderately deep, clear riverine site. Maximum detection distance for the low-frequency radio transmitter was 370 m at a depth of 1 m. It was nearly undetectable below 1 m at conductivity levels above 345 jxS/cm.

Temperature-sensing ultrasonic transmitters were implanted in adult smallmouth bass {Micropterus dolomieu) in thermally stratified Melton Hill Reservoir, Tennessee, to monitor daily summer movement. Based on energetic expectations and preferred temperatures, smallmouth bass were expected to inhabit areas with optimal temperatures except when food availability required them to move to areas of less-desired temperatures to feed. No significant changes in temperature or depth were observed during daily tracking sessions. Instead of demonstrating diel offshore/inshore movements, the fish remained in relatively warm (>28 C) water even though cooler water was available. While in warm shallow habitats, tagged fish were often associated with submerged or overhead cover. Smallmouth bass activity peaked in the afternoon and was minimal at night.

Catchability and spawning behavior of largemouth bass {Micropterus salmoides) with surgically implanted dummy transmitters and bass without transmitters were compared during 1992-1994 in a 0.20-ha pond. There was no significant difference between catchability of transmitter and control bass (P < 0.05) and spawning behavior of male transmitter and control bass (P < 0.05). Female transmitter and control bass were observed being courted by male bass on nests.

Partners in Flight, the Neotropical Migratory Bird Conservation Program, has generated interest among land managers to integrate songbird management into traditional management objectives. Confusion often exists, however, about which bird species or species assemblage to manage on any particular management unit. I describe 1 method for land managers to determine breeding bird priorities for any particular management unit and provide, as an example, nesting songbird priorities and management recommendations for the Cheatham Wildlife Management Area in Tennessee. Abundance and frequency of occurrence of several bird species was analyzed at different geographic scales to show the management area's importance to the species.

The Texas Parks and Wildlife Department Wildlife Division is proposing to establish regional “wetland ecosystem” teams to coordinate wetland related activities on state-owned and private lands in Texas. The Central Coast Wetland Ecosystems Project (CCWEP) was the first of these teams to form. Project staff are responsible for daily management, maintenance, and research activities on state-owned areas, as well as providing management assistance to private landowners and coordinating surveys for American alligators (Alligator mississipiensis) and colonial waterbirds on the central Texas coast. CCWEP staff will employ traditional and innovative land management practices, primarily for waterfowl. Ecosystem monitoring, however, will be aimed primarily at documenting the response of vegetation, neotropical birds, small mammals, reptiles, amphibians, and fish-togame management practices.

From 1980-1981, we tested the hypothesis that removal of potential nest predators would increase the reproductive success of the endangered Attwater's prairie-chicken (Tympanuchus cupido attwateri). Striped skunks (Mephitis mephitis, N = 74), opossums (Didelphis virginiana, N = 83), and raccoons (Procyon lotor, N = 9) were removed from a 522-ha predator removal area (PR) during February- June 1980 and 1981. Predator indices were lower (P < 0.002) and prairie-chicken nest success was higher (82% vs. 33%, P < 0.019) in the PR than a 620-ha control area (CO). Breeding season hen survival was <9% on both areas and survival curves were different between PR and CO (P < 0.015). Small sample size caused by declining populations and treatment effects that were compounded with site effects make our results equivocal.

Information on winter movements and denning of Florida black bears (Ursus americanus floridanus) is important to develop habitat management programs. I studied denning characteristics and winter movements of 13 radiocollared bears (9M, 4F) in the Apalachicola National Forest and surrounding timberlands of northwest Florida from 1990-91 to 1992-93. All monitored bears denned during the study. Pregnant females entered dens earlier (P < 0.02), emerged later (P < 0.02), and denned longer (142 ± 5 [SE] vs. 52 ± 7 days) than other bears. Denning periods for pregnant females were similar to those reported from other Southeastern black bear populations. Males denned for short periods (¯x = 51 ± 8 days, N = 8). One male bear, which denned during winter 1991-92, remained active during winter 1992-93, using a range of 37 km2. All males, even when they denned, ranged widely during winter (¯x = 18 ± 7 km2).

A geographic information system was developed for lower Melton Hill Reservoir and the adjoining Clinch River in eastern Tennessee to demonstrate the feasibility of using this tool to identify potential bald eagle (Haliaeetus leucocephalus) breeding habitat in the southeastern United States. Input variables in the model included land use, forest type, condition and size, distance from water, distance from human development,and acreage of aquatic foraging area. The primary limitation on habitat suitability in the Clinch River-Melton Hill Reservoir area was human development (residential and industrial) along shoreline areas. Eagle management strategies developed from the model included locating future development away from high-quality habitats, allowing forest stands near water to mature, conducting timber stand improvement (thinning) to foster growth and development in pines and hardwoods, and using eagle introductions to foster development of a breeding population.

Winter resources may limit bird populations. In this study we document the winter bird community and assess habitat relationships in a single large loblolly pine (Pinus taeda) plantation (~500 ha) from shortly after establishment into the middle-age closed canopy stage at 16 years. The winter bird community changed as the plantation grass/forb/shrub community gave way to low shrubs, and again as low shrubs were dominated and mostly supplanted by the rapidly growing pine trees. The highest bird abundance (436/km2) and the most species (22) occurred the second year after planting (the first year of the study). After the second year post establishment, the number of species declined and bird abundance declined consistently until about year 10 when pine canopies dominated. From age 10 to 16 years of the plantation, number of bird species was variable and bird abundances were low and variable. Bird species diversity was variable throughout the study.

Small mammals were trapped annually in Canaan Valley, West Virginia, from 1978 to 1993. Canaan Valley is located at 1,000 m elevation in the Appalachian Mountains and contains an unusual interspersion of ecological communities. Snap-trapping was conducted for 4 consecutive nights each September in each of 11 habitat types: alder, aspen, conifer, grassland, grassland/ecotone, hayfield, young hardwoods, mature hardwoods, muskeg, shrub/ecotone, and spiraea. The most abundant species captured were deer mice (Peromyscus maniculatus, 2.0 captures/ 100 trapnights), short-tailed shrew (Blarina brevicauda, 1.6), meadow vole {Microtuspennsylvanicus, 1.1), masked shrew (Sorex cinereus, 0.8), and red-backed vole (Clethrionomys gapperi, 0.3). Mean annual trap success for all sites combined varied significantly within years, ranging from 1.7 to 10.6 captures/100 trapnights in the 16-year period.

Evaluating the contribution of wading bird populations to avian biodiversity and wildlife managers' ability to maintain viable wading bird populations requires accurate information on population levels and trends. Wading bird population surveys often use multiple observers in single or over multiple years, but inter-observer variability is seldom evaluated. We conducted a study to test for significant inter-observer variability among experienced biologists and to determine the impact of variability on biologists' ability to accurately survey colonies and to monitor statewide trends in colonial wading bird populations. Interobserver variability was not significantly diiferent, but statistical power was low. Based on the results of this study, we believe that an analysis of inter-observer variability should be a component of any wading bird survey that includes multiple observers in single or over multiple years.

Herbicides are frequently used in pine stands to control competing hardwoods. We investigated the longevity of 4 species of hardwood snags (mockernut hickory [Carya tomentosa], sweetgum [Liquidambar styraciflua], southern red oak [Quercus falcata], and post oak [Q. stellata]) after treatment with 2,4-D herbicide. In addition, we observed evidence of foraging activity and cavity excavation by cavity-nesting birds. Hickory and sweetgum were the least durable; by the fifth year only 16% of sweetgum and 47% of mockernut hickory snags remained standing, and only 11% of the original snags of each species was standing the sixth year post treatment. The oaks were somewhat more durable with 44% of southern red oak snags and 65% of post oak snags remaining by the sixth year. However, by the eighth year only one-fourth of these original snags remained. Bird foraging activity began the first year for sweetgum, the second year for post oak and the third year for southern red oak and hickory.