Journal of the Southeastern Association of Fish and Wildlife Agencies

Most studies examining salmonid diets and their relationship to invertebrate drift are confined to periods from spring through early fall. Invertebrate drift generally decreases from spring through summer and fall seasons and is greatest during diel periods of low light. Salmonid feeding efficiency is reduced under low light conditions and several studies have found them to feed primarily through the daylight hours. Drift feeding salmonids are also size selective. The purpose of this study was to determine if patterns of invertebrate drift and brook trout feeding seen during warmer times of the year hold during the post-spawning fall and winter for brook trout (Salvelinus fontinalis) in the central Appalachians. The general diel pattern of invertebrate drift and salmonid feeding found during spring and summer months in other studies was less obvious during the post-spawning fall and winter for brook trout. Total invertebrate drift density did not follow a diel pattern.

The objective of this study was to evaluate the use of a 508-mm minimum length limit in conjunction with a 1-fish-per-day creel limit to determine its effectiveness in improving the size structure of the brown trout (Salmo trutta) fishery resource in the Lake Cumberland Kentucky tailwater. The ultimate goal is to increase the number of trophy (>508 mm) brown trout within the tailwater. When sample sites were combined, a significant increase in brown trout CPUE was seen across years for all size-classes. The time required to detect this increase in trophy brown trout was approximately 4 years and was dependent on growth. On a site-by-site basis, however, variability between sites tended to mask findings of significance. Such variability may lead to important management implications when planning a large tailwater-stocking regime. This study has shown that the trophy regulation resulted in increased numbers and sizes of brown trout within the Cumberland tailwater.

In many Appalachian headwater streams brook trout (Salvelinus fontinalis) are the only fish species present. Land use practices or global warming can have a significant effect on the production and survival of brook trout in these streams. Managers must be able to evaluate the potential impact of thermal changes upon these streams and bioenergetics models represent a valuable tool in this effort. Here we present a bioenergetics model for brook trout and conduct a laboratory validation of the model. Model validation experiments showed the model to adequately predict the growth, final weight, and consumption of fish in the experiments. Growth and final weight were estimated within -1.4% (not significantly different than 0) and consumption was slightly underestimated, within -19.7% (± 7.5%) of observed values.

Brook trout (Salvelinus fontinalis) is the only salmonid native to the southern Appalachian Mountains. The range of brook trout within this region was greatly reduced during the 20th century due to environmental degradation and the introduction of non-native rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta). Efforts to supplement trout populations and to repopulate streams in which trout had been extirpated also included stocking of hatchery-reared brook trout, the stocks for which originated from northern populations. Recently, molecular genetic analyses have demonstrated there to be distinct differences between brook trout native to the southern Appalachians and those found north of this region. In the present study, the genetic origin was determined for wild brook trout populations within 37 streams in the upper French Broad River system, Transylvania and Henderson counties, North Carolina.

Twenty-eight populations of brook trout (Salvelinus fontinalis) in Georgia were genetically compared using isozymes and their genetic relatedness determined. Eight populations (29%) were classified as southern based on fixation for CK-A2*122 allele, 2 (7%) populations were classified as northern based on fixation for CK-A2*100 allele, and the remaining 18 (64%) were northern-southern hybrid populations. All 8 southern populations shared some variant alleles with northern populations. Northern brook trout in Georgia had much greater genetic variation than southern brook trout, and hybrid populations were intermediate. Among the 8 southern populations and hybrid populations that are strongly southern, 2 major genotypes exist based on fixed or large differences at the sAAT-3* locus. Combinations of migration, non-random mating and selection are occurring, as many loci were not at Hardy-Weinberg equilibrium.

Brook trout (Salvelinus fontinalis) populations in the upper Shavers Fork, a high elevation watershed in eastern West Virginia, have been severely impacted by a loss of quality habitat. Successful restoration of these populations will require a comprehensive understanding of current habitat conditions at a watershed scale. We describe a statistically based habitat survey designed to quantify physical habitat conditions within the watershed at a range of spatial scales. Our study also addresses the following specific objectives: 1) to describe discrete hydraulic channel units that commonly occur in our study area, and 2) to identity statistical differences in the microhabitat characteristics among each of the channel unit types. We identified 5 recurring channel unit types within the basin: bluff pool complexes, riffle-run complexes, intermediate gradient riffles, low gradient riffles, and glides.

On 11 October 2000, approximately 946.25 million liters of coal slurry waste spilled from a Martin County Coal Corporation impoundment into 2 stream drainages in Martin County, Kentucky. On the same day of the spill occurrence, water quality was assessed and periodic monitoring has continued to the present by state personnel from Kentucky and West Virginia. The resulting damage to fish in the streams was the focus of intensive investigation by both the Kentucky Department of Fish and Wildlife Resources and the West Virginia Department of Natural Resources. In addition to water quality measurements (pH and dissolved oxygen) an assessment of the fish kill in Coldwater Fork, Panther Fork, Wolf Creek, and the Tug Fork River, was conducted. The loss of fish resources from the streams were calculated based on existing data, and American Fisheries Society monetary values were utilized for assessed value.

Many fisheries management agencies incorporate benthic macroinvertebrate metrics in stream assessment, yet concern exists over regional variability in metric sensitivity and the reproducibility of results over time. Two field experiments were conducted in Mullenax Run, Pocahontas County, West Virginia during summers 1999 and 2000 to investigate the sensitivity of benthic macroinvertebrate metrics to fine sediment and annual variation. Substrate composition of fine sediment (< 2mm) was manipulated from 0%-40% in 10% increments in 0.3-m2 circular trays arrayed in 2 sections of the study stream. The trays were allowed to colonize for 5 weeks in each year. In 1999, Ephemeroptera, Plecoptera, and Trichoptera, (EPT) taxa richness (R2=0.144, P=0.0031) was negatively related to increasing fine sediment while % Climber (R2=0.217, P=0.0019) was positively related to increasing fine sediment.

Benthic macroinvertebrates were sampled in July 2000 and April 2001 at 12 sites in the Smith River below Philpott Dam in southwestern Virginia. One riffle in each site was stratified into upstream, middle, and downstream transects and Surber samples were collected at 2 randomly-selected locations on each transect. Macroinvertebrates were identified to family and each sample was measured for wet weight. Family richness was calculated and simple linear regression was used to evaluate longitudinal trends in mean abundance and wet weight with increasing distance from the dam. We found low values of family richness near the dam but richness more than doubled by 4.2 km downstream. Mean wet weight and abundance of macroinvertebrates were higher in April than in July and Ephemerellidae proportionately dominated the samples in April. Overall, abundance of aquatic invertebrates in this tailwater was lower than expected for a stream of this size in Virginia.

Ozark hellbenders (Cryptobranchus alleganiensis bishopi) are large aquatic salamanders found in flowing waters. The abundance of this species is thought to have declined over the long term. What had been the most abundant population, in Spring River, Arkansas, appears to have declined precipitously in the last decade. The possibility of supplementing the population through captive propagation has been suggested, raising concerns about genetic issues. Random amplified polymorphic DNA (RAPD) was evaluated for assessing genetic variability among and within populations of Ozark hellbenders from Spring River (Ark.), Eleven Point River (Ark.), and North Fork White River (Mo.). Six primers were tested, and all generated reproducible RAPD profiles. Forty RAPD bands were generated of which 20% exhibited within-population variation and an additional 5% exhibited between-population variation.

The voltage gradients of electric fields produced by electrofishing boats are important in determining sampling efficiency and the potential for injuring fish. We evaluated 10 electrofishing boats and found that 3 boats had malfunctions that could impact sampling or operator safety. The in-water voltage gradients were measured for the remaining 7 boats to make comparisons among boats and to determine the voltage gradients present during electrofishing. For all boats evaluated, the cathode was the aluminum boat hull, and the 2 anode arrays each consisted of 3-11 droppers (cables, chains, or rods; 0.6-1.2 m long) suspended from a boom in front of the boat. A grid (1.5 x 2.0 m) was attached to the anode support booms between the anodes and the bow of the boat; this grid facilitated measurements of voltage gradients in the portion of the electric field where most fish are captured.

We analyzed relationships between largemouth bass (Micropterus salmoides) recruitment and environmental characteristics in Skiatook Lake, Oklahoma, from 1997 through 1999. Catch rates of young-of-year (YOY) were positively associated with inflows into the reservoir during the spawning season (April-May), whereas juvenile catch rates were positively related to reservoir releases during the post-spawning period (Jun-Nov). Abundance of juvenile fish in fall electrofishing samples increased from 1997 through 1999. No evidence of over-winter mortality was detected. Estimated swim-up dates for young-of-year largemouth bass were later each year from 1997 to 1999. Growth of YOY largemouth bass was not correlated with any of the measured environmental variables.

In temperate reservoirs, habitat quality and availability can be vital to year-class formation of young largemouth bass. We assessed littoral habitat availability for largemouth bass in a tropical reservoir. Habitat characteristics (slope, substratum, and cover) were measured at 5 water levels (169, 170, 171, 172, and 173 m above mean sea level) at 15 30-m sites in Lucchetti Reservoir. Total structural habitat availability declined sharply at lower water levels, and both inundated terrestrial vegetation and woody debris were absent at the lowest water level examined. Coarse substrates (gravel, cobble, and boulder) were more common at higher water levels, and fine substrates (primarily clay) dominated at lower water levels. Annual catch rates of age-1 largemouth bass from 1993-2000 were significantly related to estimated mean structural habitat availability for the previous spawning season.

We described seasonal movements of smallmouth bass (Micropterus dolomieu) in Lake Moomaw, a 1,024-ha western Virginia impoundment, using ultrasonic telemetry in combination with a mark-recapture tagging study. Documentation of lake sections occupied over the course of a 2-year period was used to assess the extent and magnitude of spring migrations of bass to the headwaters of the reservoir. Fish using the headwaters during the spring were drawn mainly from adjacent areas within 9 km of the headwaters, although fish from as far away as the dam were recovered in the headwater area. Use of the headwaters by smallmouth bass from the lake was estimated at less than 20% of the adult population during the spawning season. Redistribution information was also collected and showed that smallmouth bass returned to areas previously occupied prior to spawning.

Diet and growth of the 1993 year-class of age-0 largemouth bass were determined in Ledbetter Embayment of Kentucky Lake. Diet was analyzed to determine the relationship between diet quality and the resulting size structure of the cohort. Length-weight and head capsule-weight regressions were used to estimate the dry weight of prey items in the diet. Largemouth bass were divided into 2 size classes (large and small) based on the mean length for each sampling date. Growth rates were calculated for both classes and compared with piecewise linear regression of total length on day of the year with the use of an additional dummy variable. There was a pivotal period in mid-July when there was a divergence in growth rates. The growth rate of small age-0 fish slowed dramatically, while the growth of large age-0 largemouth bass increased.

Briery Creek Lake is a 342-ha impoundment in central Virginia that has become widely recognized as having Virginia's premier trophy largemouth bass (Micropterus salmoides) fishery. We estimated largemouth bass density (fish/ha) using a multiple census mark-recapture technique along a 3.2-km section of shoreline and by using the Leslie catch-depletion technique in a 4.1-ha cove. An access point creel survey was conducted in 1999 and 2000 to estimate angler catch and harvest. We used a dynamic pool model to simulate the effects of a newly imposed 356-610 mm protected slot limit with respect to size structure, harvest, yield, and abundance of trophy (?560 mm) largemouth bass. The mark-recapture study estimated largemouth bass density to be 44 fish/ha and the number of trophy largemouth bass in the lake to be 318. The Leslie catch-depletion technique estimated the density of largemouth bass to be 43 fish/ha and the number of trophy fish to be 397.

Striped bass fingerlings (Morone saxatilis) acclimated to hard water (110 mg/liter as calcium carbonate, 41.0 mg/liter as calcium) were exposed for 96 hours at pH 7.7, 6.1, or 4.2 in hard water. In another experiment, striped bass fingerlings acclimated to soft water (32 mg/liter as calcium carbonate, 9.5 mg/liter as calcium) were exposed for 96 h at pH 7.7, 6.1, or 4.2 in soft water. No mortalities occurred during the experiments. The primary stress response and electrolyte disturbance were less severe in fish acclimated to hard water than in fish acclimated to soft water, suggesting that calcium acclimation history may be an important consideration when stocking striped bass into acidic waters.

The aquifer that supplies water to most channel catfish (Ictalurus punctatus) hatcheries in the Yazoo Basin of the Mississippi River flood plain in west-central Mississippi has a hardness of <10 mg/liter as CaCO3. Calcium hardness <10 mg/liter is known to reduce survival and growth of catfish sac and swim-up fry, but effects of low hardness on fingerling growth and survival have not been determined. We examined the effects of hardness (5 mg/liter and 67 mg/liter as CaCO3) on survival and growth of fingerling (2.0-3.2 g initial weight) channel catfish (USDA-103 line), blue catfish (I. furcatus, D&B line), and channel X blue catfish hybrids (USDA-103 channel X Rio Grande blue catfish) in 80-liter aquaria. Survival was ?99% in all treatments over the 33-day experimental period. Low calcium resulted in significantly (P < 0.05) reduced net weight gain in both channel (4.4±0.07 g vs.

A population of catfish presumptively identified as channel catfish (Ictalurus punctatus) found in Lake Maurepas in southeast Louisiana matures at a small size and early age (<170 mm TL and <2 years) compared to other populations in southern Louisiana (>500 mm TL and 3 to 4 years). In addition, these catfish have a protracted spawning period. The peak spawning time coincides with cultured channel catfish, but a percentage of the population spawns throughout the summer months. These fish are harvested at a small size and support an important but contentious commercial fishery. The small size and early age at sexual maturity have raised several questions: are these channel catfish, a distinct subspecies, or a hybrid between channel catfish and another ictalurid? These reproductive characteristics would prove useful for research, especially if the taxonomic uncertainty could be resolved.

Algae infestations are a common problem in catfish culture ponds. To treat filamentous algae, frequent applications of copper sulfate are necessary. Free copper is toxic to fish, and its concentration is dependent on a variety of factors such as its reaction with carbonate ions, absorption by phytoplankton, and temperature. The Frankfort Fish Hatchery has been using a colorimeter to measure the concentration of free copper ion after the application of copper sulfate to ponds stocked with blue catfish and channel catfish fingerlings. The use of the colorimeter allows managers to determine when the free copper concentration has decreased enough to safely treat the pond again. It has been observed at this hatchery that blue catfish are more sensitive to copper sulfate treatment than channel catfish. During the 2000 production season, the average survival of 3 blue catfish ponds treated with copper sulfate pentahydrate was 75%.

The paddlefish (Polyodon spathula) population in the Ohio River Basin is an inter-jurisdictional resource shared by 8 states and managed with 3 different strategies, restoration, protection, and harvest. These contrasting management strategies evolved from a historical gradient in abundance of paddlefish from the upper to lower reaches, differential impact of anthropogenic factors, and U.S. Supreme Court settlements, which changed river ownership among lower Ohio River states. Ohio River Basin states participated in a national paddlefish study during 1995-1999 verifying movement of paddlefish across state boundaries in the Ohio River. Recognition that paddlefish likely represent a single population within the Ohio River and consideration of the value and vulnerability of paddlefish as a source of caviar has created a need for comprehensive and cooperative management of paddlefish among Ohio River states.

Movement, distribution, and habitat use of walleyes (Stizostedion vitreum) in Laurel River Lake, Kentucky were determined by radio-tracking 35 walleyes for 605 days (mean = 249 days) from March 1994 through November 1995. The goal of this study was to increase the angler utilization of walleyes in Laurel River Lake by educating anglers on walleye movement patterns, habitat usage, and distribution within the lake. Walleye movement (as measured in distance between weekly locations) was highest during the spring (median = 120 m/day) and lowest during the summer (median = 53 m/day). During the summer, most walleyes confined their activities to specific areas of the lake and were often located in the same area during consecutive weeks. Activity areas ranged from 2 to 590 ha with 75% of walleyes utilizing areas <300 ha. Walleyes were widely distributed throughout the lake during each season, although only 2 walleyes remained in the upper Laurel River arm during July and August.

Although fertilization has been a common practice to increase fish production in low nutrient lakes and ponds, applicability of the practice in larger reservoirs is questionable. Under the assumption that increased algal production moves up the food web to fish, we fertilized Grayson Lake, Kentucky, surface water with high N to P ratio fertilizer during springs 1994 and 1995. April through July 1994 we added 1 kg P/ha and 22 kg N/ha over a 9-week period to approximately 162 ha of lake surface area. During 1995 we increased loading to 7 kg P/ha with 22 kg N/ha. Weekly photic zone water samples were taken directly after fertilization (within 1 day). Water quality and primary production were assessed in fertilized and unfertilized lake regions. Alkalinity, inorganic nitrogen, soluble reactive phosphorus, and chlorophyll a concentrations were not significantly higher in the fertilized areas (N = 40 in 1994, N = 50 in 1995, P > 0.1 Mann-Whitney test).

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is a threatened anadromous species in the Gulf of Mexico. Nineteen subadult Gulf sturgeon were equipped with ultrasonic transmitters (34-40 kHz) in the Choctawhatchee River and Bay during fall 1996 and 1997 before their entry into marine habitat. The movement and habitat use of Gulf sturgeon in the estuarine/marine environment was determined from November through April 1996-1999. A total of 344 sonic contacts were made in this study. We documented fish location using a GPS and recorded water depth, temperature, salinity, substrate type, and distance from shore. Subadult Gulf sturgeon migration from the freshwater riverine system to the marine system was influenced by an increase in river flow and a decrease in water temperature. Fish moved throughout Choctawhatchee Bay, but mostly used shoreline areas. The use of 5 geographic areas by 95% of telemetered Gulf sturgeon may be linked to food availability.