Journal of the Southeastern Association of Fish and Wildlife Agencies

In 2004, the Southeastern Cooperative Fish Disease Project completed 40 years of research, education, and disease diagnosis in support of the fisheries management goals of the members of the Southeastern Association of Fish and Wildlife Agencies (SEAFWA). This project has been possible because of the cooperation of biologists and support from the Southeastern states. Major areas of research included parasites of warmwater sport fish, bacterial and viral diseases of fish, and environmental effects on fish health. These research topics arose from problems identified because of the disease diagnostic activities of this cooperative project. Continuing education courses provided basic instruction about fish diseases and also transferred new research information to biologists in the SEAFWA states. In addition, the training of fish disease specialists increased the availability of personnel to assist SEAFWA members.

Several diseases of fish present challenges to both fishery managers and aquaculturists in the Southeast. Emerging diseases along with a suite of known and persistent diseases can present management challenges for native species and biodiversity, can cause loss of recreational fishing opportunities, and can affect local economies or reduce profitability in commercial aquaculture. Emerging diseases such as mycobacteriosis in striped bass, epizootic ulcerative syndrome in menhaden, and spring viremia of carp present some new challenges to fishery managers. Likewise, recurring epizootics resulting from such etiologic agents as Streptococcus and Vibrio in estuarine fishes or Aeromonas and Edwardsiella in freshwater fishes have challenged managers for decades. Pathogens including Photobacterium damselae piscicida and several of the Mycobacterium species may represent health risks to managers, anglers, or fish culturists.

Cages as tools for in situ bioassays have a proven track record in monitoring the effects of effluent and sediment toxicity. Application to biomonitoring, however, has received comparably little attention. With the increasing threat of harmful algal blooms to both humans and aquatic organisms, their use as sentinels for early warning and for the examination of organism response in situ is evident. During efforts to monitor and describe the response of juvenile menhaden (Brevoortia tyrannus) to the reportedly toxic dinoflagellates of the genus Pfiesteria, we devised a simple, inexpensive cage for the conduct of in situ bioassays. This design, in combination with fish husbandry and transport techniques specific for menhaden, allows for rapid, inexpensive deployment of cages in at least a 4-h radius of the holding facility with an acceptable level of mortality and minimal caging effects.

The anesthetic properties of clove oil and tricaine methanesulfonate (MS-222) were tested in a laboratory setting on the southern redbelly dace (Phoxinus erythrogaster), a small cyprinid common to upland streams of the Mississippi River basin. We used southern redbelly dace as a surrogate species to indicate the lowest, most effective anesthetic level for our work with the closely related blackside dace (Phoxinus cumberlandensis), a federally protected species. Concentrations of 20, 40, and 60 mg L-1 clove oil and 20, 40, and 60 mg L-1 MS-222 were used to anesthetize southern redbelly dace at water temperatures of 11, 17, and 21 C, representing a natural range of temperatures encountered in research streams from spring through autumn. For clove oil, induction rates were dependent on dose, temperature, and the interaction between these two variables. Recovery rates, on the other hand, were dependent only on temperature (quicker recovery at warmer temperatures).

Raccoons (Procyon lotor) are ecological generalists that use a variety of landscape and habitat types. Although space and habitat use are well understood for raccoons throughout the southeastern United States, relationships between space use and landscape characteristics are not. We examined relationships between space use and landscape characteristics for 95 radio-marked raccoons monitored during 1996-1997 on two adjacent forested landscapes that differed in forest management strategies. We noted relationships between space use and patch richness, proportion and size of riparian habitats on the landscape, and size of patches providing soft mast resources. Raccoons within an intensively-managed forest maintained spaces with reduced patch richness and less of the landscape in riparian habitats, likely attributable to forest management strategies that optimize wood fiber production.

An understanding of spatial and temporal dynamics of wild turkey (Meleagris gallopavo) populations is essential in setting management goals. In central Texas, raccoon (Procyon lotor) populations have increased in recent years, causing concern that they may be limiting Rio Grande wild turkey (M. g. intermedia) production. We used two long-term data sets in central Texas to explore the relationship between raccoon abundance and Rio Grande wild turkey production at the regional, county, and local scale. We found no evidence that natural variation in raccoon abundance was associated with Rio Grande wild turkey production. Although further research is warranted, we suggest that raccoons may influence broad-scale Rio Grande wild turkey production in central Texas less than expected.

Annual recruitment of eastern wild turkeys (Meleagris gallopavo silvestris) should be closely monitored to regulate fall turkey seasons and reduce risk of over-harvest. However, previous studies have not encompassed the spatial or temporal scales needed to produce models that can consistently predict recruitment over a large region. Our objective was to assess the ability of using long-term data sets of sex-age ratios, oak (Quercus spp.) mast, and weather variables to forecast annual wild turkey recruitment in western Virginia. We conducted a thorough literature search on factors believed to be limiting reproduction and developed a series of 14 a priori models and 1 a posteriori model to predict recruitment.

Cost-effectiveness of various planting options is an important consideration in selecting planting strategies for mourning dove (Zenaida macroura, hereafter ‘dove') fields. We documented costs and seed yields of three cultivated and three wild dove foods, and tested effects of fertilization rate, row-spacing, and seeding rate on seed yield of highly-preferred dove foods. Browntop millet generally had the greatest seed yield and lowest cost/kg of seed produced. Broadleaf signalgrass (Brachiaria platyphylla) generally was the second highest-yielding species, but high seed cost limited cost/kg of seed produced for wild species. White proso millet, dove proso millet, and switchgrass (Panicum virgatum) produced little seed and had low cost-efficiency. Fertilization rate did not affect seed yield of the species we tested. Effects of row spacing and seeding rate on yield of browntop millet and dove proso millet varied between study sites.

Texas Parks and Wildlife Department (TPWD) has used auditory call counts annually since 1949 to monitor white-winged dove (Zenaida asiatica) populations in the Lower Rio Grande Valley of Texas. Recently, white-winged doves have been expanding their distribution, and now the largest populations occur in urban areas north of their historic south Texas range. It has become necessary to develop an urban survey method to better monitor these populations. We compared two call count sampling methods for surveying white-winged doves in urban environments (i.e., transects vs. grid-points in Austin during 1999-2002 and San Antonio during 2001-2002). We also determined the percent annual population change we were able to detect for each year with the current sample size using the grid-point survey method. Estimates of white-winged dove breeding density were higher using the transect method compared to the grid method each year.

Managers and biologists have long relied on relatively inexpensive and easily collected data from hunter-harvested deer to provide information for making harvest management decisions. We sought to better understand the influence of time lags and population segment (i.e., total adult and total herd density) on the density-physical parameter relationship. Nine long-term harvest data sets (15-31 years duration, median = 26 years) were acquired from populations located across the Southeastern United States which spanned several physiographic provinces and a wide range of densities (1-32 deer/km2). Population densities were derived from a combination of Downing and Wisconsin reconstructions. These densities were correlated to commonly used physical parameters in the current year and with one- and two-year lags. Time lags proved to be useful in identifying the relationship between physical parameters and density for both the total and adult segments of the herd.

To assess how white-tailed deer (Odocoileus virginianus) herd demographics influence reproductive behaviors, we examined 24-h diel movements of female white-tailed deer relative to parturition and breeding in a low-density population with a near even sex ratio at the Savannah River Site (SRS), South Carolina. We conducted a series of intensive, 24-h radio-tracking periods of 13 females during spring and fall 2002. We compared daily range (ha), rate of travel (m/h), and distance between extreme daily locations (m), among the periods of pre-parturition and post-parturition and pre-, peak-, and post-rut. From pre-parturition to post-parturition, we observed decreases in diel range size (-38.2%), distance between extreme diel locations (-17.0%), and diel rate of travel (-18.2%). Diel range size, distance between extreme diel locations, and diel rate of travel during the pre-rut and rut exceeded those observed during post-rut.

Long-term declines in American woodcock (Scolopax minor) populations may be partially the result of low survival rates on wintering grounds especially in nocturnal habitats. We compared microhabitat characteristics of woodcock nocturnal roost sites to random sites in eastern Texas. We located woodcock roost points by nightlighting in winters of 2000-01 (45 points) and 2001-02 (74 points). Percentage bare soil, sapling-size tree canopy cover above 0.5 m, and sapling density were greater at roost than random sites. Conversely, shrub ground cover (i.e., below 0.5 m) was lower at roost than random sites. Woodcock roosted in mowed areas, unmowed bunchgrass, under saplings treated with herbicides the previous summer, and in areas where carpetgrass had been burned the previous winter. They did not roost in unburned carpetgrass.

We evaluated short-term effects of prescribed burning of clearcuts on potential ruffed grouse (Bonasa umbellus) brood habitat in oak-hickory forests in western Virginia. We divided six <1-year-old clearcuts into two portions and designated one portion for prescribed burning during late fall or winter. Because of dry conditions, only four treatment areas were burned. We monitored habitat conditions on burned and unburned portions of clearcuts during the growing season preceding treatment and during the two subsequent growing seasons. Excessive coarse woody debris (CWD) can hinder movements of grouse chicks and inhibit growth of plant foods; prescribed burning reduced density of small-diameter CWD approximately 50%. Numbers of some early successional plants were greater on burned than control sites by the second growing season post-treatment, whereas some species associated with shaded sites, including red maple (Acer rubrum), declined after burning.

Hatching success of crocodilian eggs can be influenced by the age of the embryo at time of collection. We conducted an experiment to determine the amount of care necessary during egg collection to optimize embryo survival when alligators eggs at different stages of development were subjected to simulated field conditions of choppy vs. smooth water and cushioned vs. non-cushioned support. We also compared hatching success of rolled vs. non-rolled eggs at different stages of development. We found that transporting eggs in choppy water reduced hatch rates in the absence of cushioning (P < 0.001) and cushioning improved the likelihood of eggs hatching (P = 0.071). The hatch rate probability of eggs with 7-8 days of embryonic development was less than those of 12-14 or 17-18 days (P < 0.010). Rolling did not significantly affect the probability of eggs hatching (P > 0.89) for the ages 13-24 days. This study indicated that precautionary measures can reduce egg mortality.

Avian vacuolar myelinopathy (AVM), a disease of unknown etiology, was first diagnosed in 1994 (Thomas et al. 1998) as the cause of morbidity and death of American coots (Fulica americana) and bald eagles (Haliaeetus leucocephalus) in the southeastern United States. The disease, now confirmed on 10 lakes in four southeastern states, also has been found in mallards (Anas platyrhynchos), ring-necked ducks (Aythya collaris), bufflehead (Bucephala albeola),one great horned owl (Bubo virginianus), and a killdeer (Charadrius vociferous). Histological examination of the central nervous system (CNS) shows a striking diffuse, spongy degeneration of the white matter, especially in the optic tectum and cerebellum. However, assessments of epidemiology, histopathology, and environmental chemistry/toxicology have failed to determine the cause.

We conducted a survey of nonindustrial private (NIP) landowners in Mississippi during the 1996-97 and 1997-98 hunting seasons to determine revenues collected and expenditures incurred for fee hunting on their properties. We mailed the survey to random samples of landowners who owned $16.4 ha within statewide and Mississippi Delta counties during 1996-97 and statewide and Mississippi Gulf Coastal counties during 1997-98. Questionnaires mailed over the two hunting seasons totaled 6,966 and resulted in 2,283 respondents. Game species pursued on lands committed to fee hunting included deer, waterfowl, turkey, quail, dove, and “other” game. Respondents reported expenditures for overhead items and wildlife management activities related to fee hunting on their lands. Two hundred thirty-six respondents reported gross revenues from fee hunting ranging from US$2,964 to $5,254 on average per landowner or $7.50 to $14.28 per ha, depending upon the region.

As part of a statewide regulation change in 1990, Texas Parks and Wildlife Department adopted 254-mm minimum length and 25-fish daily bag limits on crappies (Pomoxis spp.) at Sam Rayburn Reservoir. The objective of the regulation was to increase the size of harvested crappies while maintaining pre-regulation catch rates, harvest rates, and yield. Population and fishery parameters during 3-year unregulated and 8-year regulated periods were compared. Results indicated that mean length and weight of harvested crappies increased significantly (16% and 40%, respectively), while yield was maintained. Significant increases in trap net catch rates of crappies, coupled with a 36% increase in angler catch rates, suggested an increase in stock-length crappie abundance during the regulation period.

Between the early and late 1990s, a nearly 10-fold decline in angler catch rates of large (?2.27 kg) largemouth bass (Micropterus salmoides) was observed in Wheeler Reservoir, Alabama. The objective of our study was to estimate the exploitation rate of largemouth bass and compare predicted population responses from simulated minimum length limit (MLL) regulations in an attempt to explain this reduction. Exploitation was seasonal, with most of the harvest occurring during spring. Spring and early summer exploitation estimates adjusted for tag loss and angler non-reporting ranged from 10% to 15% in 2001, 9% to 14% in 2002, and 6% to 10% in 2003. No fish were reported as harvested in the first four months following tagging in October 2002. Simulation modeling predicted that a 406-mm MLL could potentially increase by 56% the proportion of a cohort that would recruit to 508-mm (approximately 2.27 kg), compared to a 305-mm MLL.

Roving-clerk creel surveys were conducted at Cat Island, Mississippi, during two three-year periods: 1977-1979 and 1997-1999. Angler interviews provided data of species caught with estimated weight and number, as well as duration of fishing activity. Periodic aerial counts of fishermen provided further estimates of total fishing activity. Fishing pressure increased significantly (P ? 0.05) during the 20-year study interval in numbers of fishermen and total hours fished. Greatest fishing activity occurred on weekends during both study periods with the greatest fishing pressure from March- November. Despite increased fishing pressure, total catch did not increase significantly (P ? 0.05) between study periods. Catch per unit effort (CPUE) exhibited a decline proportionate with the increase in fishing pressure.

We examined the effects of an aquatic herbicide (Aquathol K) applied prior to largemouth bass spawning to reduce the exotic submersed macrophyte hydrilla (Hydrilla verticillata) and promote establishment of native submersed plants on largemouth bass (Micropterus salmoides) population metrics. Density and biomass of adult (>250 mm) largemouth bass were determined between 2000 and 2003 using a catch-depletion technique in a cove that had been periodically treated with herbicides. Also, catch-per-effort for both number and weight were compared in 2002-2003 between a treated and untreated hydrilla-infested cove. In the cove where catch-depletions were conducted, herbicide applications reduced hydrilla between 2000-2003 and abundance of native plants increased. Coincident with these changes, largemouth bass density and biomass increased 50% to 120%. Over time, the size of fish captured increased in this cove, but temporal changes in relative weight were not evident.

Alewife (Alosa pseudoharengus) was introduced into oligotrophic Mayo Reservoir, North Carolina, during 1992 or 1993. The species established a self-sustaining population and increased from <1% of total fish biomass in 1993 to 31% in 2000. Size-selective planktivory by the species, a well-documented phenomenon in other alewife introductions, was implicated in observed changes in the reservoir zooplankton community. Large- and mid-sized zooplankton (> 0.7 mm) (Onchyodiaptomus birgei, calanoid copepodites, Daphnia spp., Diaphanosoma brachyurum, and Holopedium gibberum) decreased in density and biomass within a year after the alewife introduction. Total cladoceran densities and biomass and total copepod biomass also exhibited the same pattern. Conversely, smaller or more evasive zooplankton (e.g., Bosmina longirostris, Mesocyclops edax, Tropocyclops prasinus, cyclopoid copepodites, and rotifers) either increased or did not change in abundance following introduction.

A spawning population of Cycleptus meridionalis was sampled 71 times in the generator outflow area below Millers Ferry Lock and Dam from 1995-2003. Sampling success ranged from 32 fish in 2001 to 247 fish in 2003. Sixty-seven percent of 1059 fish captured were males; 30% were females, and 3% were gender unknown. Females attained a greater total length and total weight than males. Regression slopes for standard length versus total length and total weight versus standard length were significantly different (P<0.01) between males and females. Collections of >100 fish indicated peak spawning activity occurred in late March when water temperatures ranged from 15 to 17 C. Most fish left the spawning area when water temperatures reached 20 to 21 C. Twenty percent of 702 Cycleptus meridionalis anchor tagged from 1995-2002 were recaptured from 1996-2003.

We conducted a mail survey to evaluate the demographics, attitudes, and practices of Alabama licensed freshwater anglers. The survey consisted of 36 questions that largely paralleled the most recent (1987) previous angler survey conducted by Alabama Department of Conservation and Natural Resources. Of the 2000 surveys mailed to randomly-selected licensed anglers, 31% (628) were returned before the stated deadline. Responses were similar to those in the last statewide survey. Tournament anglers represented only about 5% of respondents. The most sought freshwater fish species by respondents was largemouth bass (Micropterus salmoides). Anglers demonstrated a greater desire to release rather than harvest fish, with reasons for releasing fish including the expectation of improving fishing and fear of contaminants.