David R. Bayne

Impact of silver and bighead carps on plankton communities of channel catfish ponds

Abstract Stocking of ponds with planktivorous carps in polyculture with channel catfish ( Ictalurus punctatus and a hybrid) reduced the density of zooplankton when compared to controls. Bighead ( Aristichthys nobilis ) and silver carp ( Hypophthalmichthys molitrix ) similarly reduced zooplankton, though the mechanism of suppression may be different. Phytoplankton biomass was significantly higher in ponds containing bighead and silver carp. Ammonia and nitrite concentrations were similar in bighead and silver carp ponds and were significantly lower than in control ponds.

Growth of Freshwater Drum from Lotic and Lentic Habitats in Alabama

Abstract We analyzed variations in the age and growth of freshwater drum Aplodinotus grunniens in Alabama rivers and reservoirs. Lotic environments produced significantly more robust freshwater drum (associated with higher growth rates) than did lentic settings. Shorter reservoir retention times (more lotic reservoirs) also produced more robust and faster-growing freshwater drum, which supported the hypothesis that hydraulic-based habitat was an important variable in determining freshwater drum condition and growth. Linear declines in relative weight and percent lipid were revealed along a hydrologic gradient in Lake Logan Martin and were strongest in older freshwater drum. Von Bertalanffy predictions supported these results but also exposed a unique caveat: If freshwater drum lived long enough (>12 years), they were ultimately able to grow to larger sizes (>L ∞) in reservoirs. Freshwater drum may be capable of moving between available lentic and lotic habitats during their lifetime to maximize invertebra...

Supplemental feeds containing coffee pulp for rearing Tilapia in Central America

Abstract A supplementary feed containing 30% coffee pulp was evaluated for use in the culture of Tilapia aurea in El Salvador, Central America. A comparison of the coffee pulp feed with a feed containing all of the same ingredients except coffee pulp was made with T. aurea raised in 1.0-m 3 cages suspended in a fertilized earthen pond. Survival was high in all treatments and there was no significant difference in average weight gain between groups of fish receiving the two experimental feeds. Production trials were conducted in 100-m 2 fish pens and in 0.05-ha earthen ponds. Pen-raised fish receiving coffee pulp feed grew faster throughout the experiment, and total production was approximately twice that in control treatments. Highest production in pens was 1.25 kg/m 2 per year. Results of production pond trials using T. aurea at 9 000/ha and stocked with the piscivorous Cichlasoma managuense yielded an estimated 3 392 kg/ha per year in fed treatments and 2 049 kg/ha per year in controls. Low feed conversion (1.92) and low feed cost resulted in an increase in net annual earnings of

Zooplankton, Fish and Sport Fishing Quality Among Four Alabama and Georgia Reservoirs of Varying Trophic Status

251.00/ha.

Recruitment control and production of Tilapia aurea (Steindachner) with the predator, Cichlasoma managuense (Günther)

ABSTRACT Four mainstream river impoundments located in Alabama and Georgia were examined in 1989 and 1990 to determine the response of zooplankton and fish to trophic gradient. Mean chlorophyll a concentrations ranged from 2 μg/L in the mesotrophic lake to 34 μg/L in the highly eutrophic lake. Two of the lakes were moderately eutrophic with mean chlorophyll a concentrations of 13 and 15 μg/L. Rotifer and total zooplankton densities increased with increasing trophic status, but crustacean zooplankton densities and biomass did not. Estimates of fish abundance and biomass were positively related to trophic state. Forage fish community structure in the mesotrophic lake was numerically comprised of Iepomid sunfish (47%), cyprinid minnows (20%) and shad (Dorosoma) (13%), but shad comprised 45% to 53% of the fish community in the eutrophic lakes. Black bass (Micropterus spp.) growth rates were similar in all lakes, however crappie (Pomoxis spp.) grew faster in the more eutrophic reservoirs. Fishing effort adjust...

Changes in the Black Bass Community and Fishery with Oligotrophication in West Point Reservoir, Georgia

Abstract The effects of different stocking rates and ratios of Tilapia aurea (Steindachner) in combination with Cichlasoma managuense (Gunther) on tilapia recruitment and production were evaluated in 440 m 2 ponds. The research was conducted at the National Fisheries Station in El Salvador, Central America. The tilapia A T value, the total weight of marketable tilapia (14 cm or larger) expressed as a percentage of the total weight of the whole tilapia population, averaged 96 or greater at a stocking ratio of 4:1 (fingerling tilapia: fingerling C. managuense ) and at a stocking ratio of 8:1 (fingerling tilapia: adult C. managuense ). Tilapia A T values at a stocking ratio of 8:1 (fingerling tilapia: fingerling C. managuense ) ranged from 71–89. Highest estimated annual production of marketable tilapia (3611 kg ha −1 ) occurred at the highest stocking rate of 12000 tilapia ha −1 in populations with an average tilapia A T value of 98. Greatest weight gain of marketable tilapia (167 g of 1.17 g day −1 ) occurred at the lowest stocking rate of 6000 tilapia ha −1 in populations with an average tilapia A T value of 99. Estimated annual production of marketable C. managuense ranged from 212–414 kg ha −1 . The average weight gain of marketable fish varied from 48–60 g (0.32–0.40 g day −1 ). The average C. managuense , A T value was 54, ranging from 29–84. The estimated production of marketable fish of both species at stocking rates of 6000, 9000 and 12000 tilapia ha −1 in populations with tilapia A T values of 96 or greater averaged 3295, 3290 and 4025 kg ha −1 per year, respectively.

Relative Motility of Fishes in a Southeastern Reservoir Based on Tissue Polychlorinated Biphenyl Residues

Abstract We examined the fishing tournament and population responses of largemouth bass Micropterus salmoides and spotted bass M. punctulatus to the oligotrophication of West Point Reservoir (10,467 ha), Georgia. State-mandated reductions in point- and non-point-source phosphorus loadings, primarily from the Atlanta metropolitan area, resulted in a decline of nearly an order of magnitude in total phosphorus concentrations (TP) entering the reservoir from the late 1980s to 1999. Concurrent with this decline in TP, chlorophyll-a concentrations at a midreservoir station declined from more than 40 μg/L in 1987–1988 to 9–17 μg/L by 1997–1999, which was lower than the goal of 27 μg/L. Chlorophyll-a concentrations near the dam forebay were less than at the midreservoir station and also declined over time. Largemouth bass recruitment decreased and spotted bass recruitment increased. Growth rates of age-4 and older largemouth bass and the relative weight of preferred–memorable (38–51 cm) fish declined. Slower grow...

Impact of Paddlefish on Plankton and Water Quality of Catfish Ponds

Abstract Our objective was to investigate the potential utility of polychlorinated biphenyl (PCB) residues in fish tissue as an indicator of the relative motility of fish species in Lake Logan Martin, a 6,179-ha reservoir located in east-central Alabama. Choccolocco Creek, a midlake tributary, was the site of deposition of PCBs and this embayment had the highest concentrations of PCBs. The relationship between PCB concentrations in fish muscle tissue and the distance of the fish, at capture, from the Choccolocco Creek embayment was used to infer the relative motility of 12 species of warmwater sport and commercial fishes. Regression analyses of PCB concentration versus distance suggested that species ranged from low motility (highly significant regression and relatively high R 2) to high motility (insignificant regression or relatively low R 2). Centrarchids were relatively immotile, moronids were relatively motile, and flathead catfish Pylodictis olivaris exhibited the most motility. Our results reflect ...

DDT contamination of benthic macroinvertebrates and sediments from tributaries of Wheeler Reservoir, Alabama

Abstract The effects of paddlefish (Polyodon spathula) on zooplankton, chlorophyll α, total ammonia nitrogen, and nitrite in a yearling paddlefish-catfish polyculture were measured in eight 0.04-hectare ponds. All ponds were stocked with channel catfish (Ictalurus punctatus) and the hybrid, channel catfish x blue catfish (Ictalurus furcatus), at commercial stocking rates and four ponds were stocked with paddlefish at a rate of 990/hectare. In the paddlefish treatment, zooplankton densities were significantly lower, particularly during the period March through May. Some recovery of the zooplankton occurred June to September. Seasonal mean chlorophyll-α concentrations were significantly higher in the paddlefish treatment, apparently because of reduced zooplankton grazing pressure. Dissolved nitrogen was related inversely to chlorophyll-α concentrations. The unchecked growth of the algal community (particularly of colonial forms) in the paddlefish treatment apparently interfered with efficient feeding of pad...

Do fish growth rates correlate with PCB body burdens

Residues of DDT (1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane) were measured quarterly during 1983–84 in bottom sediments and benthic macroinvertebrates from heavily contaminated sections of Huntsville Spring Branch (HSB) and Indian Creek (IC), backwater streams on Wheeler Reservoir (Alabama). Bottom muds from both channel and overbank locations contained mean concentrations of DDTR (DDT and its metabolites) ranging from 12 to 2,730 ppm (dry weight). Sediment DDTR were highest in HSB at stations closest to the original DDT source. Stations in IC, downstream from HSB, had progressively lower DDTR as distance from the DDT source increased. Macroinvertebrate DDTR measured from several stations suggested bioaccumulation of residues mainly through food webs; however, at the most contaminated locations, substrate and mode of life appeared to override trophic level effects in determining DDTR in the benthos. There is apparently an upper limit to the amount of DDTR these organisms usually accumulate. For example, detritivore DDTR from channel sediments at two stations just downstream from the DDT source averaged 125.1 and 157.9 ppm, respectively, although sediment DDTR at these two sites averaged 2,730 ppm and 96 ppm, respectively. Benthic macroinvertebrates in the highly contaminated sediments of HSB and IC apparently acquire DDTR from water, sediments, and food.