Browsing by Author "Brett JR"

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    Cage culture of seven fish species in a power plant effluent characterized by wide salinity fluctuations. 8. Annu. Meet. World Mariculture Society; San Jose (Costa Rica); 9 Jan 1977
    (1977 1977 Jan 9) Holt R; Strawn K Ayles GB; Brett JR
    Seven fish species, including freshwater, estuarine, and marine species, were cultured in floating cages between 22 July 1973 and 18 August 1975 in intake waters and at five stations in the cooling lake of an upper Galveston Bay, Texas, power plant. Cooling water was characterized by acute salinity fluctuations which adversely affected growth and survival of all species. Black drum was the only species which exhibited growth suitable for commercial production. However, black drum could not adapt to prolonged low salinities and suffered complete mortality. Striped mullet, stocked in the lake, survived the entire 2-year culture period, but growth rates were low. Pinfish and Florida pompano grew slowly and succumbed to low salinities while sea catfish and Atlantic spadefish could not tolerate low temperatures nor prolonged low salinity. Death of channel catfish occurred after conductivity levels increased above 20 millimhos/cm
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    The culture of black drum (Pogonias cromis) in cages receiving effluent from a power plant. 7. Annu. Meet. World Mariculture Society; San Diego, CA (USA); 25 Jan 1976
    (1976 1976 Jan 25) Holt RS; Straw K Ayles GB; Brett JR
    Black drum (P. cromis) were cultured from 17 June 1974, until 15 May 1975, in 0.16 m SUP-3 cylindrical cages in the plant intake water and in heated effluent at stations 1, 2, and 3 located increasing distances from the inlet of the once-through 1053 ha cooling lake of an upper Galveston Bay electric generating station. All caged drum died at the intake station by 12 November, while survival during summer and fall (17 June-19 November, 155 days) was 97% or higher at all stations in the cooling lake. Survival during winter and spring was poor with complete mortality occurring by 11 January, 9 May and 15 May at stations 1, 2, and 3, respectively. Deaths were associated with periods of poor water quality due to heavy rainfall and resultant low salinities. Intake water was the most variable in salinity while changes were less extreme and not as sudden as the effluent moved through the lake resulting in greater survival of fish at more distance stations. During summer and fall greatest mean daily length and weight gains, recorded at station 3, were 0.60 mm/day and 0.98 g/day, respectively. Food conversion values ranged from 3.56 for drum in a cage at station 3 to 48.44 for a cage of drum at the intake. During winter and spring (20 November-15 May, 177 days) growth continued, but mean daily length and weight gains were very small (0.07 mm/day and 0.17 g/day--station 3). The length-weight relationship and standard length-total length conversion equations for drum cultured in cages are: log W = -9.861 + 2.868 (log SL) and TL = 3.426 + 1.236 (SL)
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    Submerged cage culture of fish in supersaturated thermal effluent. 8. Annu. Meet. World Mariculture Society; San Jose (Costa Rica); 9 Jan 1977
    (1977 1977 Jan 9) Chamberlain G; Strawn K Ayles GB; Brett JR
    A primary drawback for cage culture in heated effluent has been extensive mortalities due to gas bubble disease. This malady, endemic to power plant effluent, is caused by supersaturation of atmospheric gases in water. The objective of this research was to determine the effect of hydrostatic pressure as a possible remedy for gas bubble disease in the discharge canal of a Galveston Bay, Texas, steam-electric plant. Seven estuarine fishes, pinfish (Lagodon rhomboides), spot (Leiostomus xanthurus), Atlantic croaker (Micropogon undulatus), black drum (Pogonias cromis), red drum (Sciaenops ocellata), Atlantic spade-fish (Chaetodipterus faber), and striped mullet (Mugil cephalus), were caged at the surface and bottom of the 3 m-deep discharge canal where total gas saturation frequently exceeded 120% during winter months. Survival in surface cages averaged 1% after 2 weeks, while survival in bottom cages averaged 81% after 12 weeks. No supplemental food was allotted, but an abundance of small organisms was continually sluiced down the discharge canal through the cages. Winter growth rates generally surpassed those of comparable species cultured elsewhere in the cooling water system at ambient temperature and fed a prepared ration. As discharge water temperature approached 35 degree C, growth rates declined. Other factors affecting growth were cage mesh size, species type, and size of individuals. All fish were maintained in the heated effluent until thermal death to determine the upper lethal temperature limits. These results indicate that submerged cage culture in power plant effluent might offer a significant savings to the culturist by increasing winter growth rates without the expense of feeding