Abstract

Regulation of reproduction in killer whales will assist the demographic and genetic management of the population in the care of humans. An 18 year old female killer whale (Orcinus orca) was maintained on the synthetic progestin altrenogest (Regu-Mate®) from March 22, 1995 to April 15, 1996 (389 days). Daily urine samples (stored at -22°C) were analyzed for urinary pregnanediol (PdG) and estrone conjugates (EC) with an ELISA test, and biweekly serum samples were analyzed for progesterone and estradiol-β17 levels. All urinary and serum hormone levels remained at baseline during the 389 contraceptive treatment days. One day prior to the end of treatment an LH spike occurred, followed by mating two weeks later. By 42 days after the end of treatment, urine PdG and serum progesterone had risen and they remained elevated for 149 days at levels comparable to pregnancy.