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Geology topics

J. G. Geiger

Publications and source records attributed to J. G. Geiger.

17 recordsLinked to original sources
USGS2002

Performance comparisons between diploid and triploid sunshine bass in fresh water ponds

Diploid and triploid sunshine bass (white bass ??? x striped bass ???) were produced in 1990 at Florida's Richloam Fish Hatchery. Triploidy was induced with hydrostatic pressure. Fry were cultured to phase I in earthen ponds in Webster and Gainesville, FL, and transported to Leetown, WV, where they were held in circular flow-through fiberglass tanks. Ploidy of treated fish was determined with a Coulter counter and triploids were segregated from diploids. In April 1991, control diploid and triploid populations were graded to remove the largest and smallest individuals, and four 0.2-ha hypalon-lined ponds were stocked with 600 fish each; two ponds contained triploids and two contained diploids. Triploids and diploids were not significantly different in average fork length (FL) or weight at stocking. Triploids averaged 231 mm and 181.2 g, compared to diploid averages of 233 mm and 188.9 g. Monthly samples indicated that diploids grew faster than triploids; mean weights and lengths were both significantly different after 3 months. When harvested in October, triploids averaged 358 mm and 867.9 g, whereas diploids averaged 381 mm and 1153.5 g. Survival of triploids and diploids was 97.0% and 95.9%, respectively. Mean standing crop was 2496.3 kg/ha for triploids and 3280.6 kg/ha for diploids. Male diploids and most female diploids were sexually mature at 2 years of age. Sterility of triploids was confirmed as gonads remained reduced and dysfunctional at 5 years of age. ?? 2002 Elsevier Science B.V. All rights reserved.

Aquaculture↗
USGS1985

Feeding habits of larval and fingerling striped bass and zooplankton dynamics in fertilized rearing ponds

Fertilization of freshwater striped bass rearing ponds with cottonseed meal or chicken manure and chicken litter in combination with liquid inorganic fertilizers and zooplankton inoculation were evaluated in 10 0.04‐ha (0.10 acre) ponds over a 4‐week period. Chlorophyll α levels and pH were significantly higher, and alkalinity and Secchi disk visibility significantly lower, in ponds fertilized with cottonseed meal. Ponds fertilized with cottonseed meal produced more crustacean zooplankton than did ponds fertilized with chicken manure and chicken litter. Fish survival and production averaged 63% and 49 kg/ha (43.7 lbs/acre) in ponds fertilized with cottonseed meal and 46% and 26 kg/ha (23.3 lbs/acre) in ponds fertilized with chicken manure and chicken litter. Adult copepods and small cladocerans were the dominant food items found in the diets of the fish.

Progressive Fish-Culturist↗
USGS1982

Effects of chronic exposure to simazine on the cladoceran, Daphnia pulex

The effects of chronic exposure to simazine, an s-triazine herbicide, on the cladoceran Daphnia pulex were evaluated under laboratory conditions. The daphnids were exposed to simazine concentrations corresponding to previously calculated 48-hr LC5 and LC20 values and the effects on survival, growth, reproduction, and behavior were monitored daily for 26 days. Survival of D. pulex in 20 mg/L simazine averaged 9.6±1.7 days. Most mortality in 4 mg/L occurred between days 21 and 25, and 65% of the daphnids were dead by day 25. Simazine interfered with molting, and growth was reduced in both concentrations tested. Reproductive maturation was delayed by about one molt cycle (3 days at 20°C) in D. pulex exposed to 4 mg/L simazine and was prevented in daphnids exposed to 20 mg/L. Numbers of live young and broods produced by daphnids in 4 mg/L were significantly lower than those produced by controls.

Archives of Environmental Contamination and Toxico↗
USGS1982

Zooplankton production and manipulation in striped bass rearing ponds

Zooplankton production and survival of striped bass fry ( Morone saxatilis ) were examined in ponds treated either with organic fertilizer (in 1980) or with a combination of organic and liquid inorganic fertilizers and inoculated with Daphnia pulex (in 1981). In 1980, there were significant differences in water quality variables and chlorophyll α levels among treatments in three series of three ponds fertilized only with different amounts of ground hay. Production of crustacean zooplankton was low, and rotifer populations increased as the number of crustaceans was reduced by predation. Electron transport system (ETS) activity was low in all treatments. Survival of striped bass differed greatly within and between treatments, ranging from 1 to 64% and averaging 17%. In 1981, water quality variation was less among treatments in four series of three ponds inoculated with Daphnia and fertilized either with chicken litter-chicken manure in combination with liquid ammonium nitrate and phosphoric acid, or with ground hay. Rotifer species were less abundant and numbers of crustacean zooplankton, total protein, and ETS activity were higher than in 1980. Survival of striped bass in 1981 ranged from 1 to 96% and averaged 45% in the ponds fertilized and inoculated with Daphnia . Numbers of striped bass fingerlings produced per hectare and percent survival were significantly greater in 1981 (manure-fertilized ponds) than in 1980 (hay-fertilized ponds). Combinations of organic and liquid inorganic fertilizers and zooplankton inoculation are suggested to develop and maintain the zooplankton forage base in striped bass rearing ponds. Management effort (including the amounts and timing of organic and liquid inorganic fertilizers) should be shifted to maximize crustacean zooplankton foods during the period 2 weeks before and 2 weeks after the fish are stocked.

Aquaculture↗
USGS1982

A review of pond zooplankton production and fertilization for the culture of larval and fingerling striped bass

Successful culture of the planktivorous fry of warmwater fish species such as striped bass ( Morone saxatilis ) depends heavily upon the composition and density of zooplankton established in rearing ponds during the 4–6-week culture period. The paper reviews the growth, reproduction, and succession patterns of zooplankton in ponds, organic and inorganic pond fertilization, and predator—prey relationships as they relate to the culture of striped bass fingerlings. Based upon this information, a pond management strategy is proposed using combinations of organic and liquid inorganic fertilizers and crustacean zooplankton inoculation to develop and maintain the zooplankton forage base in striped bass rearing ponds.

Aquaculture↗