Journal of the Southeastern Association of Fish and Wildlife Agencies

The relationship between the decline of macroinvertebrate standing crop and the loss of aquatic habitat due to box-cut access channel construction was assessed on Lake Tohopekaliga. Channelization of natural lake bottom had an adverse effect on benthic productivity by increasing both taxon richness and numbers of organisms routinely utilized by sportfish. For this study, channel substrate supported only 54% of the total standing crop of fish food organisms found in littoral substrate. Macroinvertebrates associated with vegetation were eliminated by the destruction of rooted macrophytes; approximately 420 fish food organisms were lost for every cubic meter of vegetated water column altered by channelization. It was estimated that an average standing crop of 840,000 fish food organisms would be lost due to the construction of a "standard" 200 X 10 X 2 m box-cut access channel.

Fish species diversity and abundance were examined over a 3 year period at 6 study sites within a single watershed in the Piedmont of South Carolina. The fish community was dominated by 3 cyprinid species, but included 22 species. Average Shannon-Weaver fish species diversity estimates ranged from 0.15 to 1.87, and were related to substrate diversity. Fish species diversity increased downstream, and decreased in relation to silt in the substrate and frequency of drying. Fish abundance increased downstream and with depth, but was also influenced by substrate characteristics known to influence distribution of aquatic insects.

Florida coastal waters contain more permitted artificial fishing reef sites (ca. 150) than any other state. Initiative stems primarily from local interests, including over 60 different private and public organizations. Florida's earliest reef was authorized in 1936 although 87% were proposed after 1962. Prevalent reef materials include some combination of concrete rubble, tires, automobiles and/ or vessels in 40% of Florida reefs, followed by vessels (25%), and automobile bodies and tires (13% each). Statewide resource agencies and educational organizations have fostered local reef building through financial assistance with construction, streamlined permitting procedures, information transfer via advisory services for siting and publications, and coordination of research, which has yet to address the economic impact of recreational reef fisheries.

The relationship between fish size and the activity of certain liver enzymes was assessed in age I rainbow trout (Salrna gairdneri) from 3 Virginia streams. Total length and body weight of the trout differed significantly among streams. Activity of glutamate dehydrogenase and aspartate aminotransferase also differed significantly among fish in the streams and both were negatively correlated with fish size. Differences in size and enzyme activity probably relate to differential caloric intake of fish in the 3 streams. Condition factor and alanine aminotransferase activity of the trout did not differ among streams.

Adult Florida (Micropterus salmoides floridanus) and northern (M. s. salmoides) largemouth bass were subjected in the laboratory to low water temperature regimes similar to those occurring on Texas hatcheries. Northern largemouth bass survived all temperature regimes experienced. Florida largemouth bass suffered mortality that increased as temperature decline rate (1, 2, and 4 C/ day) increased. They survived prolonged exposure (30 days) at 4 C well, but total mortality occurred at 3 and 2 C. Northern largemouth bass were more tolerant than Florida largemouth bass of rapid temperature decreases and low temperatures.

Agonistic behavior and social dominance relationships between similar-sized, wild, adult brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) were examined in a laboratory stream. Frequency of movements, aggressive encounters, and consumption of food items by trout when held as single specimens, intraspecific pairs, and interspecific pairs were compared. Rainbow trout were more mobile, aggressive, and successful foragers on drifting prey than brook trout; however, neither species appeared to possess a competitive advantage in establishing social dominance or displacing interspecific rivals. Brook trout were dominant in 9 of 14 interspecific matches. Female trout were dominant in 6 of 10 opposite-sex matches. Dominant trout, regardless of species or sex, exhibited significantly greater mobility, aggressiveness, and feeding success than subordinate trout.

Twenty largemouth bass (Micropterus salmoides) , 10 containing dummy radio transmitters and 10 control, were studied in hatchery ponds to determine the effects of implanted transmitters on swimming, feeding, spawning and catchability behavior. Eight additional bass were subjected to buoyancy compensation tests under laboratory conditions. Pond studies indicated no significant difference in swimming movement or catchability between transmitter and control bass. Both transmitter and control bass were observed feeding and spawning. All transmitters were encapsulated in a skin-like sac within the body cavity at study termination. Laboratory experiments indicated the negative buoyancy of the transmitters affected bass temporarily, and fin beats increased only during the time it took bass to adjust to the effect of the transmitter.

The spawning period and caloric density of body tissues during gonadal recrudescence were studied in a naturalized population of rainbow trout (Salmo gairdneri) from September 1979 to August 1980. As judged by gonosomatic indices and the percentage of spent females in semimonthly samples, the fish spawned from mid-February to early April, when water temperature and stream flow were both increasing. Decreases in calorific equivalents (cal mg-1 dry weight) of selected tissues during gonadal maturation in fall and winter were greatest in fat reserves along the alimentary tract.

Liberty Lake was stocked with fingerling largemouth bass (Mieropterus salmoides) at 448/ha in July, 1980. Monthly electrofishing samples collected for 1 year following stocking showed 76.4% of the 1980-year-class to have been stocked. A bimodal length distribution of stocked fish appeared in fall, 1980 and continued throughout the sampling period. Decreased survival of the stocked largemouth bass during the winter was noted. Most mortality occurred in the slower-growing fish. However, a decline in the number of fish from both length modes was evident.

Rainbow trout (Salmo gairdneri) were fed 38% protein experimental diets which contained either sunflower or soybean meal. Fish were reared in 2 sets of tanks under controlled and ambient water temperatures during January-April 1982. With controlled water temperature, fish fed the sunflower meal diet had a significantly higher final weight, average gains and food conversion ratio. Under ambient water temperature conditions, trout fed sunflower meal diet also had significantly higher final weight and average gain than trout fed soybean meal diets. A 35% protein sunflower meal adequately replaced a 49% protein soybean meal as a protein source in rainbow trout diets.

The fish fauna of Brumley Creek, Virginia, a third-order cold water stream in southwest Virginia, was sampled by electrofishing at 9 sites from headwaters to mouth. A total of 19 species were collected. Upstream sites had few species because of previous management activities. Downstream sites varied in species richness and composition as a function of several watershed characteristics. The differences in species composition among samples illustrates the problem that can occur if the fish fauna is described based on limited sampling, especially if the watershed is small and the management history is complex.

Black crappie (Pomoxis nigromaculatus) growth was reduced when hydrilla (Hydrilla verticillata) coverage exceeded 50% in Lake Baldwin, Florida, between 1977 and 1979. Black crappie did not reach harvestable size (>228 mm TL) until age 3 and 4 during periods of extensive hydrilla coverage and reduced threadfin shad (Dorosoma petenense) abundance. Following hydrilla removal and shad population reestablishment, harvestable size was obtained by age 2 and growth of older fish increased.

Shrimp (Penaeus sp.) at 50 stations throughout Alabama's estuarine area are sampled utilizing 4.9-m otter trawls, a 15.2-m bag seine and 1.8-m beam plankton trawls to monitor abundance and growth. A monthly index is determined for postlarval and juvenile shrimp by species and used each year to estimate relative abundance. A model has been developed to predict the opening day of shrimping season as much as 6 weeks in advance using estimates of brown shrimp (Penaeus aztecus) growth. Daily mean numbers of shrimp per pound collected in samples are plotted against time for growth rate estimates.

Seasonal diets of cattle and lead deer (Odocoileus virginianus) using three subunits of a rotationally burned longleaf pine-bluestem (Pinus palustrisAndropogon spp.) pasture receiving moderate yearlong grazing are compared with lead deer diets from 3 similarly managed, ungrazed subunits. Considering all plant species, diet overlap averaged 44.3, 34.7, 21.5, and 8.0% during winter, spring, fall, and summer, respectively. Summer diets were largely complementary. On the average, deer selected 15.5% more browse on ungrazed sites during winter, but 7.3 and 7.8% more browse on grazed sites during spring and summer, respectively. Prescribed burning reduced diet overlap during spring.

White-tailed deer (Odocoileus virginianus) forage was greatly increased in 2 loblolly pine (Pinus taeda) plantations after they were control burned and commercially thinned at age 13 years. Forage averaged 26 kg/ha in August 1979 (age 12) before treatment and 326 kg/ha in August 1980 (age 13),1 growing season after treatment, and 429 kg/ha in August 1981 (age 14). Deer forage averaged 31 kg/ha in February 1981 and 52 kg/ha in February 1982, which exceeded the 4.5 kg/ha average in 12-year-old untreated plantations. A 46% decline of deer forage in 1 plantation and a 26% decline in the other plantation in May 1982 compared to May 1981 indicated that the peak in deer forage occurred in the second year after treatment. Most deer forage was forbs and vines with a small woody (browse) component.

Abomasal parasite counts (APC) were determined on 467 whitetailed deer (Odocoileus virginianus) collected in summer and 436 deer collected in fall from 50 localities in the Southeast. APC values declined from summer to fall region-wide. Declines in APC values began on most areas in Mountain and Piedmont provinces by October and November, respectively; and in the Coastal Plain province declines in APC values began in November. These differences in the timing of declines in APC values precluded establishment of region-wide guidelines for interpretation of fall APC values. Since APC values did not decline until November in Coastal Plain and Piedmont provinces, the sampling period for APC studies can be extended into October in these provinces. Abomasal parasite counts performed in October or later in the Mountain province and in November or later in Piedmont and Coastal Plain provinces are lower than summer APC values and shoUld be interpreted with caution.

The relationship between abomasal parasitism and physical condition was studied in white-tailed deer (Odocoileus virginianus) in the Southeast. On both an individual animal and herd basis, the level of abomasal parasitism was inversely related to physical condition. Differences (P ≤ 0.05) in physical condition were noted among herds in each of 3 abomasal parasite count (APC) categories (namely, <500, 500-1,500, >1,500). The relationship between abomasal parasitism and herd physical condition was not cause and effect; rather, both parameters were reflective of the status of deer density relative to habitat carrying capacity. Present data verify that APC values are indicative of overall herd health. Instances in which APC data can be of particular value in deer management are discussed.

White-tailed deer (Odocoileus virginianus) activity levels were estimated by track counts on 3 study sites in the Cross Timbers region of Oklahoma during 1978-79. An activity index (number of tracks/ day) was developed from repetitive readings of 100 track plots (1 X 3 m) per site. Significant differences (P < 0.05) in monthly activity levels were found. Within-month and between-month variability was influenced by land-use patterns, ambient temperature shifts, changes in food resource availability, and deer behavior patterns. A seasonal bimodal pattern was observed, with peaks during late spring and falI-early winter, while lowered activity was observed during early spring and summer.

Percent body fat was estimated from the Kidney Fat Index for 1,726 male, white-tailed deer from the Savannah River Plant in South Carolina for the years 1974 through 1978. There was a significant decrease in percent body fat from September through December in all animals ≥2.5 years. Percent fat in fawns increased significantly from September through December. Fat levels in 1.5-year-old animals did not show a general trend for either an increase or decrease from September through December. However, the lowest percent fats were consistently observed in November for all but the 0.5-year-old males: Percent body fat was significantly related to body weight, month of collection, and age of the male, but the multiple coefficient of determination was small for this relationship (R2 =0.09). The rapid change in fat levels in males during the breeding season indicates that caution must be exercised when using the kidney fat index as a management tool.

Femurs, mandibles, and kidneys with attached perirenal fat were collected from white-tailed deer (Odocoileus virginianus) in controlled and field studies to examine the use of fat indices for assessing nutritional status. Eleven fawns were fed formulated rations differing in energy content for 4 weeks. The kidney fat index (KFI) was significantly lower for fawns fed low energy (LE) diets compared to high energy (HE) diets. Femur marrow (FMF) and mandibular marrow fat (MMF) levels were unaffected by diet. In another experiment, 9 fawns were fed diets differing in energy and protein content for 13 weeks. In this experiment, all fat indices were lower in fawns on LE diets than on HE diets. Protein intake had no effect on the fat indices. Samples also were collected from 98 captive and wild deer to examine correlations among the fat indices. A significant correlation (r = 0.44) was observed between FMF and MMF.

Winter foods of the river otter (Lutra canadensis) in southern Louisiana were determined to gain an understanding of prey eaten by otters. Otters were taken by trappers in the salt marsh in southeastern Louisiana and freshwater swamp in the Atchafalaya Basin in southcentral Louisiana. Fishes were found in 83.3% of the digestive tracts from salt marsh and 83.0% of the tracts from the swamp area. Blue crabs (Callinectes sapidus) occurred in 19.8% of the digestive tracts from salt marsh and 3.8% of the tracts from the swamp area. Crayfishes (Procambarus sp.) were found in 34.% of the swamp area digestive tracts and 1.6% of the tracts from the salt marsh. Remains of mammals were found in 7.9% of the digestive tracts from salt marsh and 7.5% of the tracts from the swamp. Other foods of otters from salt marsh and their frequencies of occurrence were birds (2.4%), mollusks (1.6%) and shrimp (1.6%).

Lithium chloride aversive conditioning to reduce raccoon (Procyon lotor) predation of loggerhead turtle (Caretta caretta) nests was tested under laboratory and field conditions. A total dosage of 1.0 g was determined to produce side effects (diarrhee and emesis) soon after ingestion, and the negative taste reaction to the drug was eliminated when a dosage level of 0.25 g/egg was administered. In separate phases of laboratory testing on 37 raccoons, an aversive conditioned response was observed in only a few individuals. During field testing, there was no significant difference (t = 1.11; P> .05) between the depredation rate on turtle nests before and after a 3-week period of LiCI treatment. Despite the administration of the drug at an undetectable dosage level with resultant physiological side effects, an effective psychological association of food with illness was not made by raccoons.

Food habits analyses were conducted on 264 diving ducks (7 species) from North and South Carolina during the 1970's. The Baltic clam (Macoma balthica) was the predominant food among canvasbacks (Aythya valisineria) from the Pamlico River area, whereas sago pondweed (Potamogeton pectinatus) predominated in birds from impoundments in North and South Carolina. Shoalgrass (Halodule beaudettei) formed 100% of the gullet food and 99% of the gizzard food in redheads (Aythya americana) from Pamlico Sound. Lesser scaup (Aythya affinis) in North Carolina had fed predominantly on mollusks (Mulinia lateralis and Rangia cuneata), whereas widgeon grass (Ruppia maritima) was the predominant food in birds from South Carolina. In North Carolina, ring-necked ducks (Aythya collaris) fed mainly on vegetation, and greater scaup (Aythya marila), bufflehead (Bucephala albeola), and ruddy ducks (Oxyura jamaicensis) fed mainly on Mulinia lateralis.

Estimates of ducks harvested by hunters from 1965 to 1975, as calculated by the U.S. Fish and Wildlife Service, were compared to corresponding estimates calculated by 33 State wildlife agencies. States were grouped into 4 categories according to survey methodology and the relative magnitude of Federal estimates to State estimates was calculated for each category and contrasts performed through analysis of variance on log transformed data. As a group, States where wildlife agencies made pre-season hunter contact produced harvest estimates that were not significantly different from Federal figures. State estimates calculated by the Southeastern Cooperative Fish and Game Statistics Project were significantly higher than Federal estimates, as were estimates from the remaining 2 groups of States where agencies did not make pre-season contact but either sampled or did not sample junior hunters.

Common moorhens (Gallinula chloropus), double-crested cormorants (Phalacrocorax auritus), and mottled ducks (Anas julvigula) were collected from phosphate-mine settling ponds and natural wetlands in north and central Florida between June and October 1981. Contents of esophagi, proventriculi, and stomachs were removed from 185 birds, identified, and measured by volumetric displacement. Aggregate percentages of food items in diets were compared between settling ponds and natural wetlands. Rank order of items in moorhen diets differed among the 2 habitats. Plant foods comprised at least 80% of moorhen diets on both habitats. Cormorants primarily consumed the same species of fish on settling ponds and natural areas. However, high numbers of mosquito fish (Gambusia afjinis) and small invertebrates were consumed on the settling ponds but not on the natural wetlands.