Abstract: This project was aimed to collect data about the ovarian cycle of the Indo-Pacific humpback dolphin, Sousa chinensis, using sonographic examination of the ovaries and serum hormone level assessment. The ovaries of two nonpregnant females were assessed at least once weekly, and one pregnant female was assessed when possible. A total of 15 normal ovarian cycles, one episode of follicular atresia, and one episode of a luteinized cystic follicle were detected using ultrasonography and serum progesterone levels. Two more cycles were detected on serum progesterone levels but not on ultrasonography. The mean ovarian cycle, mean follicular phase, mean follicle diameter measured just before ovulation, mean luteal phase, and average diameter of the corpus luteum were determined. Data showed an irregular pattern of ovarian cycling, varying between and within subjects. Serum progesterone and estradiol levels were measured one to three times per month in two females and intermittently in one other female. Recorded progesterone and estradiol levels during the follicular phase, luteal phase, and anestrus are reported. Progesterone levels during pregnancy are also included.
Key Words: INDO-PACIFIC HUMPBACK DOLPHIN; SOUSA CHINENSIS; REPRODUCTION; OVARIES; OVARIAN CYCLE; SONOGRAPHY
Document Type: Research Article
Page Numbers: 137-148