Researchers said this week that they were puzzled as to why whales and other ocean predators are targeting and killing sea lion pups at an increasingly high rate. Without a reduction in predators, the already-threatened northern sea lion species will have difficulty recovering, added the scientists.
The pups are part of the endangered western population of Eumetopias jubatus, better known as Stellar sea lions, the largest member of the eared seals family. In only four decades, the population has declined by 90 percent.
After tracking juvenile sea lions in the Kenjai Fjords and Price William Sound region of the Gulf of Alaska, researchers concluded that predation was the main cause of death among the pups. The results also suggested "predation on junvenile sea lions as the largest impediment to recovery of the species in the eastern Gulf of Alaska region." Scientists said younger sea lions spend more time close to shore, near their mothers, and as a result, predators can find them more predictably. The pups' worst enemy was expected to be transient killer whales, or orcas, as well as salmon sharks and Pacific sleeper sharks.
Researchers warned that there are not enough Stellar sea lions born each year to rejuvenate the species' population.