Mysterious Sea Lion Decline: The Game’s Afoot!
Image Credit: Wikimedia
A valuable member of the eared seal family may be in trouble, but rest assured, scientists are on the case.
The Stellar Sea Lion, whose recent unexplained decline in Alaskan waters have concerned scientists for decades, is experiencing an eerily similar decline in eastern Russia as of late. Home to relatively newer sea lion colonies, Russia’s Commander Islands saw the lowest sea lion colony birth rate in years. Only 167 pups were born in the main colony by the end their reproductive season in July.
Sergi Ryazantsev, a researcher with the Pacific Institute of Geography, monitors the main colony and says that population decline is a major concern. Why? Like Alaska, the reason for the dramatic decline is a mystery.
To further explain the extent of sea lion population decline, The Moscow Times helped put the numbers into perspective.
“The Gulf of Alaska and Aleutian Islands accounted for 74 percent of the global population in 1970s, but the number shrank to 56 percent by 1989, according to the U.S. National Park Service. The rate of the decline reached an alarming 15 percent per year in the late 1980s, according to the Alaska Department of Fish and Game”
Strangely, the decline has only affected half of the world’s sea lion populations. Sea lions are divided into two “stocks”, or groups: the eastern stock (Prince William Sound and further west) and the western stock (California through southeast Alaska, also including the Commander Islands’ colonies). The western stock happen to be the unlucky ones.
Rapidly working to halting the decline and save the species, researchers have developed several theories to explain the Alaskan decline:
- The warming trend of the mid-1970’s in the Gulf of Alaska and the Bering Sea may have been the culprit. This caused the numbers of small oily fish to drop and be replaced by less nutritional species of fish, causing an unhealthy change in sea lions’ diet, the park services said.
- Blame could be assigned to fishermen who use high-catch methods.
To slow the decline of sea lions in Alaska, new regulations were put in place to limit the usage of high-catch methods, thus reducing competition for fish. Modest increases continue today as a result of the new regulations.
Despite protective measures, only about 39,500 western stock sea lions are left. Scientists are dedicated to determining the reason for their rapid decline and working toward rebuilding the population.
The most recent data, collected in 2006, cite that only 39,500 Stellar Sea Lions are left in existence. The situation has become dire. Extinction creates an unhealthy ocean ecosystem and scientists are striving to find solutions to ensure the continued survival of these vital species so we can reap the benefits of a healthy ocean.
Source: http://www.themoscowtimes.com/news/article/sea-lion-population-vanishing-in-russia-s-far-east/503195.html
