Featured Research

from universities, journals, and other organizations

Northern Fur Seal Pup Decline: Lowest Birth Rate Since 1916

Date:
January 19, 2009
Source:
National Oceanic And Atmospheric Administration
Summary:
Researchers have marked another decline in northern fur seal pup births in the Pribilof Islands in the Bering Sea, where most of the world's population of northern fur seals gather in the summer to rest and breed.

Northern fur seal pups on St. Paul Island, one of the Pribilof Islands. A temporary mark was applied to a pup (top right) by 'shearing' dark hairs off to expose lighter hair below.
Credit: NOAA

Researchers at the National Marine Mammal Laboratory of NOAA’s Alaska Fisheries Science Center have marked another decline in northern fur seal pup births in the Pribilof Islands in the Bering Sea, where most of the world’s population of northern fur seals gather in the summer to rest and breed.

“We started seeing an over-all decline in the abundance of fur seals on the Pribilof Islands around 1998, but we have not been able to identify the factors responsible,” said Dr. Doug DeMaster, center director. “While the population trends were up in specific areas and certain sectors of the population, the Pribilof Island pup count is a major marker, and it was down by 4.9 percent since the 2006 count.”

Analysis of 2008 data produced an estimate of 121,000 northern fur seal pups born in 2008. The total number of adult males counted on the Pribilof Island increased by 4.6 percent to 10,600.

Northern fur seals are considered depleted under the Marine Mammal Protection Act. The complexity of ecosystem interactions and limitations of data and models make it difficult to determine how fishery removals may have influenced this population. Other factors which may have contributed to past or present declines of northern fur seals include entanglement in marine debris, parasites and disease, pollutants, general nutrition, and predation.

“We have a very long, scientific record of the population of northern fur seals on the Pribilof Islands and not since 1916 have the islands produced this few seal pups,” said DeMaster. “Adult male counts began in 1909 and pup counts were initiated in 1912. At that time, the northern fur seal population was rebounding at a healthy eight percent per year, following the end of extensive at-sea seal hunting.”

The northern fur seal population rose steadily from the end of unregulated sealing into the 1950s, when scientists estimated the population at about two million. A harvest of adult females from 1956 to 1968 reduced the population through the 1970s. The total Pribilof population size stabilized briefly from about 1980 through the mid-1990’s but, since 1998, the population has declined at an annual rate of 5.2 percent.

While the Pribilof Islands are the main breeding and resting areas for northern fur seals, the seals also claim other, smaller breeding areas on Bogoslof, San Miguel, and South Farallon islands in the United States and in foreign waters on the Kurile, Commander, and Robben islands. Pribilof Island fur seals spend only the summer months foraging in the Bering Sea. During the rest of the year, they migrate south of the Aleutian Islands and forage at sea.

For 2008, researchers noted an overall population increase on the smaller of the Pribilof breeding islands, St. George Island, and that northern fur seals have also been increasing at Bogoslof Island in the nearby Aleutian Island chain.

The total population of northern fur seals in the whole Eastern Pacific stock was last estimated at 666,000.


Story Source:

The above story is based on materials provided by National Oceanic And Atmospheric Administration. Note: Materials may be edited for content and length.


Cite This Page:

National Oceanic And Atmospheric Administration. "Northern Fur Seal Pup Decline: Lowest Birth Rate Since 1916." ScienceDaily. ScienceDaily, 19 January 2009. <www.sciencedaily.com/releases/2009/01/090116164521.htm>.
National Oceanic And Atmospheric Administration. (2009, January 19). Northern Fur Seal Pup Decline: Lowest Birth Rate Since 1916. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2009/01/090116164521.htm
National Oceanic And Atmospheric Administration. "Northern Fur Seal Pup Decline: Lowest Birth Rate Since 1916." ScienceDaily. www.sciencedaily.com/releases/2009/01/090116164521.htm (accessed September 17, 2014).

Share This



More Earth & Climate News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins