Thesis Title

Seasonal Reproductive Changes in Cryptobranchus Alleganiensis

Date of Graduation

Spring 1982

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Robert Wilkinson

Subject Categories

Biology

Abstract

Seasonal changes in the testes, ovaries, and oviducts were studied in Cryptobranchus alleganiensis collected from the Niangua River, Missouri, from October 1979 through October 1980. Spermatogenesis occurred from late June through early August. Length, absolute weight, and relative weight of the testes were maximal by mid-July. Breeding occurred from mid-September through early October. The testes had regressed by October. Spermatogonia occupied the regressed testes from October through June. Vitellogenic activity was greatest from May through mid-September. Absolute and relative ovarian weights and ovarian oocyte diameters were maximal during September prior to ovulation. Little change occurred in the absolute and relative ovarian weights from mid-September, after the eggs were laid, until May. Relative oviducal weights followed the same pattern as the ovaries. From October through June, 27.5% of the females had retained mature ovarian oocytes from the breeding period. Retained oocytes were undergoing atresia. Yolk elements were phagocytized by the follicle epithelium cells in the oocytes undergoing atresia.

Copyright

© Chris Alan Ingersol

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Dissertation/Thesis

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