Fresh Water Studies Commons^™

A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson

Publications (WR)

Several limnological studies have been conducted in Lake Mead during the past decade. The recent studies clearly show that most of Lake Mead is deficient in nutrients, especially phosphorus, and very low in productivity. The reservoir-wide average total phosphorus concentration for 1981 - 1982 was only 9 mg/m³. This is below levels found In most oligotrophic lakes and reservoirs. Algal biomass, as measured by chlorophyll-a, averaged only 1.5 mg/m³. That also places Lake Mead in the oligotrophic range. Transparency, as measured by a Secchi disc, averaged 9-5 m in Lake Mead during 1981-1982. That far exceeds …

Seasonal And Spatial Heterogeneity In The Limnetic Zooplankton Community Of Lake Mead, Gene Robert Wilde

Publications (WR)

Zooplankton samples collected from throughout Lake Mead, in 1981-1982, demonstrate the presence of a statistically significant seasonal and spatial heterogeneity in zooplankton densities. Seasonally, the major zooplankton groups were most abundant in the spring and fall, coincident with maxima in chlorophyll-a concentrations. Successions among the various rotifers, cladocerans and copepods present in the reservoir were influenced by food availability, diapause, predation by planktivorous fish and, possibly, water temperatures. Spatial heterogeneity in zooplankton densities was unrelated to water temperature, pH, conductivity and dissolved oxygen concentrations, but was related to the abundance of phytoplankton (chlorophyll-a concentrations) and fish. Statistical analyses indicate that …

Factors Affecting Reproductive Success Of Bonytail Chubs And Razorback Suckers In Lake Mohave, Michael A. Bozek, Larry J. Paulson, James E. Deacon, U.S. Department Of Interior, Fish And Wildlife Service

Publications (WR)

Razorback suckers (Xyrauchen texanus) and bonytail chubs (Gila elegans) were once widespread throughout the Colorado River system. The ranges and populations of these native species and others have declined in the past 50 years. Bonytail chubs appear to be extremely rare and possibly nearing extinction in the Upper Colorado River Basin. The razorback sucker is widely distributed in the upper river but is considered rare throughout most of that range and is also rare in the Grand Canyon. Razorback suckers are abundant only in a few habitats in the upper river. They congregate and spawn over …

The Growth And Feeding Behavior Of Juvenile Spot, Leiostomus Xanthurus Lacepede, In The Nursery Region Of The James River, Virginia, John Thomas Mccambridge Jr.

OES Theses and Dissertations

The in situ growth and feeding behavior of juvenile spot, Leiostomus xanthurus Lacepede, was investigated for populations in the nursery area of the James River, Virginia. Growth of juvenile spot was found to be fairly rapid (11.34 mm/month, standard length) during their first summer in the nursery grounds, but it levelled off in the autumn. The mean size of spot after the first year was calculated to be 195 mm total length. The weight-length relationship was log W = -5.018 + 3.246(log L), where W = wet weight in grams and L = standard length in millimeters.

Juvenile spot appeared …

Fisheries Report No 59 - Potential Fisheries Capability Of The Ord In The Short, Medium And Long Terms, Dr N. Morrissy

Fisheries Research Reports

This report examines the history, future and problems of various methods for development and exploitation of the fisheries resources of the Ord.

The primary resource is the array of native fish and crustacean species, with the possible introduction of other desirable or noxious species being a subject for consideration.

Water resources, supporting these species, are the remaining natural Ord River downstream from the Diversion Dam at Kununurra, the stillwaters of Lake Kununurra and Lake Argyle, and, for aquaculture, the controlled distribution of water supply over the flat land of the irrigation system (Fig. 1). Another recognized resource is the climatic …

Report No 58 - 1982 - Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro

Fisheries Research Reports

An account is given of involved the biological principles in decisions concerning duck-shooting seasons in the south-west of western Australia.

Conditions for waterfowl during 1982 are described through the use of rainfall statistics and data obtained from the Department's wetland monitoring programme.

1982 was characterized by exceptionally high rainfall in January and well-below average from February to October.

1982 was the seventh consecutive year of below-average rainfall in all five Meteorological of the south-west. 1976 to 1982 has thus been the south-west's driest seven-year period for more than seventy years.

The record-breaking rains of January caused widespread flooding in the …

The Effects Of Limited Food Availability On The Striped Bass Fishery In Lake Mead, John R. Baker, Larry J. Paulson

Publications (WR)

The original range of striped bass (Morone saxatilis) was along the Atlantic Coast. They were introduced into the lower Sacramento River in 1879 and are now also found along the Pacific Coast. A landlocked striped bass fishery was established in Santee-Cooper Reservoir, South Carolina, in 1954, and they have since been introduced into numerous other reservoirs, including Lake Havasu, Lake Mead and Lake Powell on the Colorado River. Striped bass were introduced into Lake Mead in 1969 in response to declines in the largemouth bass (Micropterus salmoides) fishery that occurred during the 1960s and in order to further utilize the …

Historical Patterns Of Phytoplankton Productivity In Lake Mead, Richard T. Prentki, Larry J. Paulson

Publications (WR)

Lake Mead was impounded in 1935 by the construction of Hoover Dam. The Colorado River was unregulated prior to then and therefore was subjected to extreme variations in flows and suspended sediment loads. Hoover Dam stabilized flows and reduced suspended sediment loads downstream, but Lake Mead still received silt-laden inflows from the upper Colorado River Basin. The Colorado River contributed 97% of the suspended sediment inputs to Lake Mead, and up to 140 x 1O⁶ metric tons (t) entered the reservoir in years of high runoff. Most of the sediments were deposited in the river channel and formed an …

Report No 56 - 1981 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro

Fisheries Research Reports

An account is given of the biological principles involved in decisions concerning duck-shooting seasons in the south-west of Western Australia.

The conditions for waterfowl which prevailed during 1981 are described through the use of rainfall statistics and data obtained from the Department's wetland monitoring programme.

Rainfall was generally average over central and northern areas of the south-west during 1981. Rainfall in southern areas, however, was generally

below to much-below-average, although south coastal areas from Augusta to Albany received average falls.

Unusually heavy falls were recorded in North Coastal, North Central and Central Coastal Districts in May, and average falls were …

Report No 47 - 1980 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro

Fisheries Research Reports

An account is given of the biological principles involved in decisions concerning duck-shooting seasons in the south-west of Western Australia.

The conditions for waterfowl which prevailed during 1980 are described through the use of rainfall statistics and data obtained from the Department's wetland monitoring programme.

1980 was the fifth consecutive year of below-average rainfall in all five Meteorological Districts of the south-west. 1976 to 1980 was thus' the south-west's driest five-year period since 1913 at least.

Low rainfall during 1980 resulted in a further decline in the condition of wetlands throughout most of the inland south-west, Few gauged wetlands increased …

Mass Marking Of Mosquitofish: Preliminary Results, Bruce Vondracek, Wayne A. Wurtsbaugh, Joseph J. Cech Jr.

Watershed Sciences Faculty Publications

Three marking techniques were tested to determine their applicability for mosquitofish. Tetracycline drugs and DC Ar administered in the diet successfully marked laboratory-cultured mosquitofish, but exposure to direct sunlight in outdoor tanks resulted in the rapid disappearance of the marks. Preliminary data on fluorescent marks from a polystyrene pigment in a melamine-sulfonamide-formaldehyde resin forced into the dermal ,tissue with compressed air are more promising.

A t an optimal deliver pressure of 7.3 m Hg (140 p.s.i.) and spraying time of 15 sec., marking percentage is maximized and fish mortality is minimized. Mark retention time was up to 80 days in …

Effect Of Fish Size On Prey Size Selection In Gambusia Affinis, Wayne A. Wurtsbaugh, Joseph J. Cech Jr., James Compton

Watershed Sciences Faculty Publications

Food size selection of the mosquitofish , Gambusia affinis affinis. was measured in aquaria using juvenile stages of the mosquito, Clllex tarsalb;, as prey. Fish size varied from recently born fry to large adult females. Food size selection was positively correlated with fish size. Mosquitofish fry (6-8 111m standard length) attacked and ate primarily first and second instar larvae. Fry attacked larger instars, but attack success on these was low (0 - 50%). Fish larger than 20 mm attached primarily pupae and third and fourth instar larva. No first instar mosquitoes were eaten. Attack success for these fish was above …

Evaluation Of Impacts Associated With Reregulation Of Water Levels In Lake Mohave, Larry J. Paulson, John R. Baker, U.S. Water And Power Resources Service

Publications (WR)

The U.S. Water and Power Resources Service is considering reregulating Lake Mohave water levels to increase the net power benefit from Hoover Dam. Reregulation will not increase the generation capacity of the Hoover powerplant but it will enable the plant operation to be increased when the energy has greater monetary value. Energy generated at different times of the year has different market value, the highest being in January-March and July- September. By generating more power during these periods more net monetary benefit can be derived from Hoover Dam. The total volume of water released from Hoover Dam over an annual …

The Relationship Of Food Conversion Efficiency And Growth Potential In Juvenile Mosquitofish, Gambusia Affinis, Joseph J. Cech Jr., Michael J. Massingill, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

New information concerning respiratory metabolic rates of juvenile mosquitofish (i = 915 mg 02 kg-1 h-1 at 20° C) was applied to existing data on mosquitofish respiration and combined with findings on growth and food consumption rates to determine percentages of net ingested energy used for growth and respiration over a 10- 35° C temperature range. The energy percentage used by mosquitofish for respiration was minimized at 25-30° C while that used for growth (= food conversion efficiency) was maximized at the same temperature. A calculated growth potential index, derived from an overall energy balance equation, was also maximized at …

Effects Of Organic Compounds On Amphibian Reproduction, Wesley J. Birge, Jeffrey A. Black, Robert A. Kuehne

KWRRI Research Reports

Aquatic toxicity tests were conducted with atrazine, carbon tetrachloride, chloroform, methylene chloride, trisodium nitrilotriacetic acid (NTA), and phenol. Each compound was administered to developmental stages of three to five amphibian species. Exposure was initiated at fertilization and maintained through 4 days posthatching. Test responses included lethality and teratogenesis. Different amphibian species exhibited varying degrees of tolerance to the selected compounds. Greatest tolerance usually was observed for the more broadly adapted semi-aquatic and terrestrial species (e.g., Bufo americanus, Bufo fowleri). The more sensitive amphibians usually included those species which normally are restricted to aquatic or moist habitats (e.g., Rana …

Influence Of Dredging And High Discharge On The Ecology Of Black Canyon, Larry J. Paulson, Theron G. Miller, John R. Baker, U.S. Water And Power Resources Service

Publications (WR)

The Water and Power Resources Service is considering dredging in Black Canyon to create a larger forebay to accommodate higher peak discharges and reverse flows for proposed modifications to Hoover Dam. The Black Canyon area from Hoover Dam to Willow Beach supports a heavily utilized trout fishery and is important habitat for the razorback sucker (Xyrauchen texanus) and possibly bonytail chub (Gila elegans). The Water and Power Resources Service initiated this investigation to determine what effect dredging and higher peak-discharges would have on the ecology of Black Canyon.

The Comparative Ecology Of Two Populations Of The Troglobitic Isopod Crustacean Lirceus Usdagalun (Asellidae), James Alexander Estes

Biological Sciences Theses & Dissertations

Aquatic communities of two caves in Lee Co., Virginia, were compared, and an examination was made of the life history phenomena of the troglobitic isopod Lirceus usdagalun. Measurements of physical and biological parameters were made in Thompson Cedar Cave and Gallohan Cave No. l. A contagious distribution was exhibited by populations of L. usdagalun in both caves and also by the population of another troglobitic isopod, Caecidotea recurvata, in Gallohan Cave No. 1. This distribution was attributed to aggregations of individuals which were considered to occur in areas of preference or optimal habitat patches. Lirceus usdagalun exhibited a …

Potential Use Of Hydroelectric Facilities For Manipulating The Fertility Of Lake Mead, Larry J. Paulson, John R. Baker, James E. Deacon

Publications (WR)

Analysis of historical nutrient data for Lake Mead indicates that the fertility of the reservoir has decreased which may be the cause for a corresponding decline in the largemouth bass population. However, it appears that fertility can be manipulated by altering the operation of the dam. The depletion of nutrients in the euphotic zone by phytoplankton and subsequent accumulation in the hypolimnion during summer and fall provide a natural nutrient gradient from which water of varying fertility can be drawn for discharge. This combined with alterations in the depth or seasonal pattern of discharge can possibly be used to enhance …

Fish Of Lake Mead And Lake Mohave, Robert C. Allan, Dennis L. Roden

Publications (WR)

This publication offers an in-depth study of the fish and other organisms that live in Lakes Mead and Mohave. The history and background of the two lakes is offered, as well as information about diseases, parasites, and unusual fish occurrences. Food sources, predation and competition are also discussed.

Fisheries Report No 27 - A Survey Of Recreational Usage Of South Coastal Estuaries Of Western Australia, N. Caputi, R C.J. Lenanton

Fisheries Research Reports

Over recent years, factors such as the State's population increase, a generally higher standard of living which enables people to have more leisure time, and better roads, particularly from the Eastern States of Australia, have all contributed towards an increase in the general recreational usage of the Western Australian south coast estuaries.

To aid proper planning of facilities to cater for an increasing number of visitors in these south coast estuaries, management agencies must be able to quantify the recreational usage in this group of estuaries.

This survey, therefore, attempts to identify and quantify the different recreational pursuits of visitors …

Fisheries Report No 26 - Report On Lake Chandala With Recommendations Of Its Importance As A Fauna Reserve, Alan Tingay, Susan R. Tingay

Fisheries Research Reports

The hydrology, vegetation, fauna and land use of Lake Chandala (31°30 'S, 115°57'E) is described on the basis of field and literature surveys. The significance of the Lake as a Straw-necked Ibis (Thresktornts spinicollis) nesting rookery is emphasised and recommendations are made for its acquisition and future management.

Fisheries Report No 16 - Notes On The Wildlife Of A Proposed Nature Reserve Around Lake Grace And Lake Chinokup, Western Australia, N. L. Mckenzie, W. K. Youngson

Fisheries Research Reports

During 1972 and 1973 plants and vertebrate animals were collected and recorded from a proposed 22 000 ha nature reserve centred on a chain of salt lakes in south-western Western Australia (33° 10' S - 33° 35' 8 and 118° 19' B - 118° 29' E).

The dominant plant species were collected, the structural formations desert bed and a vegetation map produced. Seven species of native terrestrial mammal and three species of bat were recorded.

Three of the terrestrial species are endemic to southwestern Western Australia, and two of these - Pseudomys occidentalis and Sminthopsis granulipes - are regarded as …