Journal of the Southeastern Association of Fish and Wildlife Agencies

This paper provides a mercury database for largemouth bass (Micropterus salmoides) from 80 major lakes and streams in Florida. Elevated levels (≥0.5 mg/kg) were recorded for 51 systems requiring health advisories to be issued for> 800,000 ha of aquatic resources. Significant mercury contamination was also found in other animals.

Channel catfish (Ictalurus punctatus) were sampled in 2 southeast Louisiana lakes for 3 years to determine if these populations were stunted based on age structure, growth rate, and length at maturity. Mean total length at age II for Lake Maurepas and Lac Des Allemands catfish were 262 mm and 256 mm, respectively, which compared favorably to other commercially fished populations in other areas in the lower Mississippi drainage. Channel catfish in Lake Maurepas exhibited a reduced length and age at maturity when compared to other areas. These characteristics may be due to physicochemical characteristics of the lake, an abundance of forage, or overfishing, which could select for early maturity as a survival mechanism.

Largemouth bass (Micropterus salmoides) held at lO.7 and 26.7 C in insulated fiberglass tanks were treated with rotenone and inspected daily to determine days-tosurfacing and change in body weight. Fish held at lO.7 C surfaced in 3-12 days, whereas fish held at 26.7 C surfaced within 24 hours. Fish at each temperature gained weight after death. Analysis of weight gain in fish held at 10.7 C produced no significant relationship between weight-gain and period of submergence for fish submerged 7 or more days. Weight gain was an exponential function of total length in fish held at lO.7 C and a logarithmic function of total length in fish held at 26.7 C.

Ultrasonic transmitters were surgically implanted in a total of 30 saugeye (Stizostedion vitreum vitreum x S. canadense) in 1987 and 1988. Horizontal distribution, movement, distance from shore, depth, and habitat were determined during tracking of each fish. Saugeye were located ≤65 m from shore most frequently during all seasons except summer. Saugeye preferred open shore areas, and frequented submerged timber only during fall 1988 and winter 1989 when prey items may have been limited. Saugeye preferred depths of 0-3 m except in summer 1988 and summer and fall 1989, when no depth preference was evident. Saugeye moved to a cove near the dam during late winter and early spring, which appeared to be a prespawning activity. Approximately 33% of tagged saugeye were not located in the lake during the 1988 spawning period, and 1989 tracking revealed upstream spawning movement in the Little River.

Abundance and, to a lesser degree, size distributions (in 1 of 2 sample years) of largemouth bass (Micropterus salmoides) were influenced by the presence of submerged aquatic vegetation in Flat Top Lake, West Virginia. Relative abundance and size distributions of adult largemouth bass (≥200 mm in length) were compared among high, intermediate, and low densities of submerged aquatic vegetation in September-October 1986. Largemouth bass were more abundant at high and intermediate vegetation densities than at low densities, but no differences in size distribution were noted among vegetation levels. In June and August 1987, the relative abundance and size distributions of all sizes of largemouth bass were compared between high and low vegetation densities. High vegetation contained significantly greater numbers of largemouth bass. Largemouth bass lengths were smaller in high vegetation samples, primarily due to a higher proportion of age-O fish in these areas.

Abundance and, to a lesser degree, size distributions (in 1 of 2 sample years) of largemouth bass (Micropterus salmoides) were influenced by the presence of submerged aquatic vegetation in Flat Top Lake, West Virginia. Relative abundance and size distributions of adult largemouth bass (≥200 mm in length) were compared among high, intermediate, and low densities of submerged aquatic vegetation in September-October 1986. Largemouth bass were more abundant at high and intermediate vegetation densities than at low densities, but no differences in size distribution were noted among vegetation levels. In June and August 1987, the relative abundance and size distributions of all sizes of largemouth bass were compared between high and low vegetation densities. High vegetation contained significantly greater numbers of largemouth bass. Largemouth bass lengths were smaller in high vegetation samples, primarily due to a higher proportion of age-O fish in these areas.

Nine-day-old hybrid striped bass (Morone saxatilis x M. chrysops) were stocked into fertilized O.04-ha freshwater ponds at 3 densities with 3 replications each and fed a 55% crude protein feed at 0.45 kg/day/pond divided equally into 4 daily feedings for 33 days. There were no significant (P > 0.05) differences for average weight gain or survival among the densities: 123,500 fishlha, 1.2 g, 57.4%; 247,000 fishlha, 0.7 g, 41.2%; and 370,500 fish/ha, 0.8 g, 31.8%. Fingerlings averaging 0.75 g were subsequently stocked into 0.04-ha fresh water (alkalinity ca. 100 mglliter, hardness 42 mg/liter as CaC03) ponds at 37,050/ha and 74, loo/ha (3 replications each). Brackish water (4-5 ppt) O.I-ha ponds were stocked with fingerlings averaging either 0.6 g or 1.4 g (3 replications each) at 9,880/ha. Fish were fed a 38% crude protein feed at 5% of body weight and were sampled monthly for 5 months.

Mobile hydroacoustic surveys of 11 stations in J. Strom Thurmond (JST) Lake from February 1986 to October 1988 provided data to aid in identifying critical areas, times, and water release regimes for fish relative to proposed pumpback of water from JST Lake to Richard B. Russell (RIiIR) Lake. Mean relative biomass (volts2/m2 ) usually was significantly higher in the tailrace (0-450 m below RBR Dam) than in the tailwater (1-7 kmbelow RBR Dam), tributary, or lake areas in spring and summer; whereas in fall and winter, biomass was often lower than or did not differ from that in other areas. Highest numbers of fish occurred in the tailrace from May through September, probably because ofblockage of upstream spawning migrations in spring and attraction to cold, oxygenated water released from RBR Dam in summer. Mean relative biomass in the tailwater 1-7 km below RBR Dam either was lower than that in warm-water tributaries and lake areas, or means did not differ significantly.

Density, biomass, and species composition of fish 6 em total length (TL) were determined in 4 aquatic plant communities in Lake Okeechobee, Florida, with 0.08-ha block nets and Wegener Rings (0.004 ha). Wegener Rings were placed within block nets prior to rotenone application. In Illinois pondweed (Potamogeton illinoensis), mean density and biomass estimates derived with the 2 gears were not significantly different. In eel-grass (Vallisineria americana) and hydrilla (Hydrilla verticillata) , mean density estimates derived with Wegener Rings were significantly higher than those derived with block nets, but mean biomass estimates were similar. In yellow water-lily (Nymphaea mexicana) , Wegener Rings provided significantly higher estimates of both mean density and biomass. Gear comparisons within sample sites revealed that at the highest fish densities encountered in each vegetation type, Wegener Rings provided significantly higher density estimates than block nets.

Data from August samples of fish in quarter (900 arc) hauls of a 15.2- X 1.8m bag seine were analyzed to determine effectiveness of seining for detecting species presence, forecasting future relative abundance of larger length classes of the same species, and assessing the value of seining as an indicator of prey availability for piscivores in Kansas reservoirs. The data set contained 98 reservoir-years of samples from 24 impoundments with 2-7 years of data per reservoir. The median number of hauls per reservoir and year was 19; the range was 10-30. Bag seines effectively sampled only small fish, most < 140 mm. Presence was accurately detected in 100% of the reservoir-years sampled for gizzard shad and ranged from 90% to 97% for minnows, white bass, lepomid sunfishes, and freshwater drum. Presence was detected correctly from 80% to 90% ofthe time for red shiner, largemouth bass, channel catfish, brook silverside, and bluegill but <80% of the time for other species.

We investigated the relation among estimates of abundance and size structure of white crappie (Pomoxis annularis) determined with electrofishing, trapnetting, and rotenone sampling in 4 Mississippi lakes in 1987-1989. We also examined the relations between angler harvest and estimates provided by each gear to determine whether estimates made by sampling could be used to index angling success. Electrofishing yielded 4 fish/man-hour in fall and 6 in spring, and trapnetting yielded 24 fish/manhour in fall and 9 in spring; rotenone sampling during summer yielded 8 fish/man-hour. Estimates of abundance of fish ≥20 cm long were usually correlated among gears and between seasons, but those of fish <20 cm long were not. These correlations suggest that any of these gears could be used to monitor trends in abundance of white crappie ≥20 cm long, but each would give different trends in abundance of fish <20 cm long.

Walleye (Stizostedion vitreum vitreum) x sauger (S. canadense) hybrids (saugeye) and largemouth bass (Micropterus salmoides) ≥350 mm total length were sampled in 1988 and 1989 to determine food habits and diet overlap. Shad (Dorosoma spp.) were the most important prey of both largemouth bass and saugeye. Both predators were opportunistic, eating a variety of prey items. Although diet overlap was high, competition for food was not apparent and would not be likely to occur unless forage became limited.

Food and growth of age-O hybrid striped bass (Morone saxatilis x M. chrysops) were examined during June-November 1988-1989 in Ross Barnett Reservoir, Mississippi. Shads (Dorosoma spp.), especially threadfin shad (D. petenense), made up about 70%-90% of the diet by weight. Other fish made up about 3%-20% of the diet and were eaten primarily by hybrids < 150 mm total length. Invertebrates constituted a small percentage of the diet, and were eaten mostly by fish <100 mm and not by those> 150 mm. By November, the length of age-O fish averaged 241 mm in 1988 and 227 mm in 1989. Differences in growth between years might have been caused by differences in availability and consumption of shads. Widening of hybrid length-frequency distributions in August-September coincided with reduction of shad consumption and increased incidence of empty stomachs in fish < 100 mm long, suggesting reduced availability of suitable-sized prey for smaller hybrids toward the end of the summer.

The ability of shad populations to impact the density and composition of zooplankton populations has led to the suggestion that planktivorous shad may compete with young-of-year bass for plankton food resources and influence bass recruitment. We studied the feeding dynamics of concurrent year classes of threadfin shad (Dorosoma petenense) , gizzard shad (D. cepedianum) , and largemouth bass (Micropterus salmoides) in a North Carolina reservoir to determine the nature of feeding interactions among the species. Shad planktivory was found to be confined to a brief period early in the growing season coincidental with peak zooplankton densities, after which both shad species shifted to detritivory. Only limited correlations between shad diets and zooplankton dynamics were identified. Patterns of feeding and growth in young-ofyear bass showed no indication that plankton resources were limiting cohort development.

Stomach contents of 434 largemouth bass (Micropterus salmoidesfloridanus) were collected with clear acrylic tubes. Sixty-four percent of the bass contained food. No significant differences (P > 0.05) in percent recovery of food items by weight occurred among 3 biologists for the 6 size groups studied. Greater than 80% recovery by weight of all food was obtained with acrylic tubes in 6 size groups of bass ranging from 100 to 590mm TL. Seven percent of bass that yielded no food when sampled with tubes actually contained food. Appropriate tube size was important in efficient food extraction. Largemouth bass > 120 mm can be tubed easily and efficiently. Although considered an easy and efficient technique for largemouth bass> 120 mm TL, limitations involving fish size, prey size, and incomplete recovery should be considered when interpreting food habit data obtained by acrylic tubes.

We inspected 17 fox enclosures and interviewed 26 operators to collect information on enclosure characteristics and use in Florida. Size of enclosures (N = 26) ranged from 30 to 360 ha (¯x = 108 ha). Red fox (Vulpes vulpes), gray fox (Urocyon cinereoargenteus), and coyote (Canis latrans) stocks were obtained from states in the southeast and midwest. Operators (54%) preferred coyotes exclusively or in combination with foxes: coyotes were admitted to be present in ≥35% of enclosures visited. Owners reported enclosure costs to be $40/ha. Fox enclosures provided a convenient recreational opportunity for houndsmen in an increasingly urban landscape.

We examined the influence of acorn abundance on fall and winter diets and on nutritional and reproductive status of white-tailed deer (Odocoileus virginianus) in the Southern Appalachians from 1983 to 1988. When acorns were abundant, they dominated the diet; when they were scarce, leaves of broadleaf evergreen species, primarily rosebay rhododendron (Rhododendron maximum), largely replaced acorns in the diet. When acorn production was poor, kidney fat indices in winter were significantly lower for most sex and age classes. Also, reproductive rates of yearling does were significantly lower, and conception dates were significantly later when acorns were scarce. Reproductive rates of adults were not appreciably affected by acorn abundance. Because acorn abundance is largely independent of deer density, the important role of acorns in deer nutrition presents special problems in deer management.

Gosling survival of a resident flock of Canada geese (Branta canadensis) was studied on a 2,750-ha reservoir in Fairfield County, South Carolina, in 1987. The brood-rearing season began in early April and ended in early June. A final count of all goslings on the reservoir 4 weeks after the last nest hatched yielded a gosling survival rate of 4.4%. Only 6 (15%) of 40 goslings from 10 broods equipped with radiotransmitters survived to 8 weeks of age. Gosling survival was estimated as 21.2% ± 0.15% (95% CL), using the Kaplan-Meier survival estimator that censors disappearances and 4.0% ± 0.04% (95% CL) assuming disappearances as deaths. Primary predators included red fox (Vulpes vulpes), crow (Corvus spp.) and unknown avian.

Wild turkey (Meleagris gallopavo) hens were monitored by telemetry from January 1987 through August 1988 in Kemper County, Mississippi. Thirty-nine of 52 hens reached incubation. Nesting success was 46% in 1987 and 36% in 1988. In 1987, all 12 located nests were in loblolly pine (Pinus taeda) plantations. Eleven hens nested in 17- to 19-year-old plantations; I hen nested in a 9-year-old plantation. In 1988,21 located nests were in plantations and I hen was in a mature pine-hardwood forest. Most hens (81 %) nested in plantations age 13-20 years old. Plantations used for nesting had been commercially thinned an average of 4 years (3-6 years) and had been control burned an average of 3 years (1-7 years) before being used. Hens with 1- to 14-dayold poults used mostly plantations (81 %) 14-20 years old in both 1987 and 1988. These plantations had been thinned and burned 3-4 years prior.

During late winter 1988 and 1989, 18 radio-marked eastern wild turkey (Meleagris gallopavo sylvestris) hens released into Natchez Trace State Park, Forest and Wildlife Management Area (Natchez Trace), and 20 radio-marked Natchez Trace (resident) hens released at the capture site were monitored continuously throughout the nesting and brooding season. Introduced turkeys experienced greater mortality than residents, especially during the 30-day period following release (P <0.05). Introduced birds displayed more frequent and greater daily movements than resident hens. Spring home ranges of introduced hens were larger (P = 0.02) than residents. During the initial nesting season, released birds had fewer nesting attempts, renesting attempts, nests to completion, and lower recruitment rates than resident hens (P <0.05).

During autumn 1985, we investigated waterbird use of Open Marsh Water Management (OMWM) ponds and use of natural ponds in an adjacent impoundment in Maryland. Dabbling ducks used ponds with dense widgeongrass (Ruppia maritima) more than ponds with sparse or no widgeongrass (P <0.01). Wading birds and shorebirds used the natural ponds more than the OMWM ponds (P <0.01), mainly because the OMWM ponds had vertical sides and were too deep (¯x = 0.42 m) to allow foraging. Pond surface areas were positively correlated with numbers of birds (P <0.05) and inversely correlated with densities of birds (P <0.01).

We determined immediate impacts of clearcutting on breeding bird communities of a tidally-influenced bald cypress (Taxodium distichum)-tupelo (Nyssa spp.) wetland located in the Mobile-Tensaw River Delta, Baldwin County, Alabama, April-June 1987. Seventeen of 45 species detected in first-year clearcuts, forestclearcut edges, and 70-year-old reference stands demonstrated significant (P <0.05) differences in abundance across habitat type. Three species preferred forest interior, 5 preferred edge, 7 preferred interior and edge over clearcut, and 1 preferred clearcut and edge (P <0.05). Species richness (S) from known sample size decreased from edge (36) to forest interior (27) to clearcut (21). Twice as many detections were made in a clearcut with snags retained, as in a more complete clearcut.

We marked fawns and adult white-tailed deer (Odocoileus virginianus) on 2 south Texas areas during 1986-88. Deer sighted on repeated helicopter flights were evaluated to determine if the age ratio of sightings matched the known ratio of marked fawns-to-adults in the populations. There was a trend toward undercounting fawns on each area.

Wood duck (Aix sponsa) broods were counted 15 of 19 years (1973-90) using the night-float technique on a 1O.8-km segment of the Holston River, eastern Tennessee. Broods were counted 9 years before and 6 years after the initiation of September hunting seasons. Mean harvest (¯x = 26,797, SE = 2,130) of wood ducks in Tennessee after September hunting began was 279% higher (t = 7.50, P = 0.0001, df = 14) than the mean harvest (¯x = 9,604, SE = 845) before September hunting. The adjusted mean number of broods (¯x = 7.25, SE = 1.25) observed following initiation of September hunting was significantly (F (1,8) = 16.78, P = 0.00035) less (52%) than the adjusted mean (¯x = 15.22, SE = 1.49) observed prior to September seasons. These results suggest a negative relationship between numbers of broods observed and September hunting.