In a report set for publication in the journal Biology of Reproduction, the team, headed by Dr. Todd R. Robeck, based at SeaWorld San Antonio, notes that their research will allow sperm of killer whales in zoological facilities to be stored by a technique known as "genome resource banking" or GRB. GRB, used in conjunction with artificial insemination, could play an important role in ensuring the genetic vitality of captive marine mammals.
Robeck's team studied one male and five female killer whales to evaluate the reproductive physiology of these animals. The females were between 13 and 20 years old and weighed about 5,000 pounds. The male was 20 years old and weighed more than 11,000 pounds. All were trained to cooperate in a variety of procedures involved in the research.
Noninvasive techniques were used to collect data on reproductive hormonal patterns of the killer whale, and ultrasound exams helped establish the time of ovulation.
Semen collected from the male orca for use in the artificial insemination trials was either liquid-stored for up to three days or preserved by freezing and later thawed.
Eight attempts at artificial insemination over the course of two years led to three pregnancies, one from thawed sperm and two from liquid-stored sperm. One male calf and one female calf were born. The third pregnant female, who died of unrelated causes, was carrying a male fetus. Paternity tests confirmed that all three calves resulted from artificial insemination.
Although killer whales are common throughout the oceans of the world, the population in zoological facili
Contact: Dr. Todd R. Robeck
Society for the Study of Reproduction