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Geology topics

J.G. Stanley

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

8 recordsLinked to original sources
USGS1976

Production of hybrid, androgenetic, and gynogenetic grass carp and carp

Hybridization, androgenesis, and gynogenesis were studied as potential methods for creating nonreproducing populations of fish. Hybrids from crosses of female grass carp (Ctenopharyngodon idella) X male carp (Cyprinus carpio, Israeli mirrow variety) died during embryonic development. Hybrids of the reciprocal cross hatched and were stocked in ponds, but most died within 3 months. Dimensions of the nuclei of erythrocytes from hybrids indicated that survivors were polyploid. Androgenetic grass carp and gynogenetic carp were both observed in this reciprocal cross. Gynogenesis occurred in 3% of the eggs from grass carp fertilized with UV‐irradiated milt from carp. Nuclear dimensions of androgenetic and gynogenetic fish suggested a diploid karyotype. The yield of 7,862 gynogenetic grass carp is evidence that this method might be practical for production of monosex fish for experimentation.

Transactions of the American Fisheries Society↗
USGS1974

Nitrogen and phosphorus balance of grass carp, Ctenopharyngodon idella, fed elodea, Egeria denea

The herbivorous grass carp fed winter elodea exhibited a negative nitrogen balance in metabolism, suggesting that food having a higher protein content would be required for normal growth. About a third of the phosphorus contained in food was retained; hence, a combination of aquatic plants and grass carp might afford an effective biological method for removing phosphorus from water. Water quality was altered by the excretion of ammonium and orthophosphate by grass carp. Even though the grass carp might be useful in removing some phosphorus from water, its principal impact was to increase the rate of recycling of nitrogen and phosphorus.

Transactions of the American Fisheries Society↗