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R.M. Harrell

Publications and source records attributed to R.M. Harrell.

4 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↗
USGS1998

A comparison of triploid induction validation techniques

Triploidy induction is a technique that allows genetic manipulation of chromosome number to control reproduction and potentially create faster‐growing animals; however, most methods for inducing polyploidy are not 100% effective. Using sunshine bass (white bass Morone chrysops ♀ × striped bass M. saxatilis ♂) as a model, we cross‐validated the most common verification techniques: DNA staining and fluorescence quantification with a flow cytometer, erythrocyte nuclear volume with a Coulter counter particle size analyzer, silver staining of nucleolar organizer regions (NORs), and cytological karyotyping. Results indicated that the electronic techniques of particle size analysis and flow cytometry were the simplest and quickest methods of validation. The major drawback of both electronic ploidy determination methods is the cost of the equipment required for analysis. Cytological karyotyping was the most accurate method for determining polyploidy because actual chromosome numbers were determined. It was also the most time‐consuming, tedious, and frustrating of the techniques, which reduces its applicability in mass screening of fish. Silver staining was the least expensive technique used for verifying a nominal number of fish, but it was also the most suspect because the NORs were sometimes difficult to detect, and there were conflicting results in older fish. All techniques demand a certain technical competence that can either be self‐taught or requires extramural training.

Progressive Fish-Culturist↗