Great Expectations: Alaska SeaLife Center Confirms Steller Sea Lion Pregnancies
PHOTO: Courtesy of the Alaska SeaLife Center
Seward, AK – May 16, 2013 – Alaska SeaLife Center scientists recently announced that they have reached a major milestone in efforts to learn more about Steller sea lion reproduction: Eden and Tasu are pregnant!
Last summer, breeding was facilitated by housing Eden, Tasu and Sitka, three of the Center’s female sea lions, in the same habitat with Woody, a 20-year-old male. Ultrasound examinations have confirmed pregnancies in Tasu and Eden, who are both thirteen years old; however seven year-old Sitka is not pregnant. While scientists and veterinarians report that both Eden and Tasu are carrying a normally developing fetus with a healthy heart rate, they are careful to point out that they are cautious in their optimism regarding the ultimate outcome.
“If all goes well, we expect the pups to be born early this summer, and we anticipate breeding the sea lions again in 2013,” said Dr. Lori Polasek, a marine mammal scientist at the Alaska SeaLife Center and research assistant professor at the University of Alaska Fairbanks. “Because wild Steller sea lions often mate within two weeks of giving birth, females are pregnant and lactating the majority of their lives. If we want to understand this endangered population, it is important to study nutritional and physical demands on a female that is pregnant and supporting a nursing pup at the same time.”
These studies will complement research completed over the past 16 years, including the Chiswell Island video monitoring project that has closely followed reproduction of wild Steller sea lions on an island 35 miles south of Seward.
Steller sea lions typically mate in June when males and females are hauled out together on rookeries. Fertilized eggs do not begin developing until the fall, and pups are born the following June. “There is limited information on pregnant Steller sea lions in collections so we cannot predict the date of birth, but we continue to monitor the pregnancy via ultrasound,” said Brett Long, the Center’s husbandry director.
In order to mimic what would occur in the wild, preparations are underway to allow Woody to breed with the same three females again this summer after successful delivery of the pups. At 20 years old, Woody is older than the majority of breeding male Steller sea lions in the wild. According to Long, “He has led a less competitive life at the Alaska SeaLife Center, and is currently healthy and showing no signs of slowing down. However, due to his advancing age, we plan to retire Woody from the breeding program after the 2014 season.”
The Alaska SeaLife Center is a private non-profit research institution and visitor attraction which generates and shares scientific knowledge to promote understanding and stewardship of Alaska’s marine ecosystems. The Alaska SeaLife Center is an accredited member of the Association of Zoos and Aquariums and the Alliance of Marine Mammal Parks and Aquariums. For additional information, visit www.alaskasealife.org.