HOME >> BIOLOGY >> NEWS
Killer Whales Have Begun Preying On Sea Otters, Causing Disruption Of Coastal Ecosystems In Western Alaska

ported by several lines of evidence, Estes said. First is the sudden increase in observed attacks. A careful statistical analysis found it extremely unlikely that the cluster of recent observations was due to chance alone.

The researchers also compared sea otter populations at two sites on Adak Island, one an open bay and the other an area inaccessible to killer whales. From 1993 through 1997, sea otter numbers were stable in the protected Clam Lagoon, while in the adjacent Kuluk Bay they declined by 76 percent.

According to calculations based on the team's observations in one section of the Aleutian Islands, killer whales must have killed 6,788 sea otters per year between 1991 and 1997 to account for the observed decline in the population. Taking into account the number of hours of field observations by the research team during this period, the number of those attacks they could expect to have observed is 5.05, which is very close to the actual number of six observed attacks.

The researchers ruled out other possible causes of the sea otter decline, such as disease, toxins, and starvation, Estes said.

"It took about two years for me to become convinced that killer whales were responsible, as we dismissed one possibility after another and gradually gathered direct evidence pointing to killer whales," Estes said.

Terrie Williams, an associate professor of biology at UCSC and coauthor of the paper, analyzed the caloric value of sea otters, which are a less nutritious food source than killer whales' usual prey because they have very little blubber. Williams estimated that a single killer whale would need to eat 1,825 otters per year to meet its energy requirements. These figures suggest that as few as four killer whales feeding exclusively on sea otters could have driven the population decline observed over a large area of the Aleutian archipelago.

Sea otters were nearly extinct by the early 20th century due to overhunting for the fur trade. Pr
'"/>

Contact: Tim Stephens
stephens@cats.ucsc.edu
831-459-2495
University of California - Santa Cruz
15-Oct-1998


Page: 1 2 3 4

Related biology news :

1. Killer virus
2. Tracking A Killers Progression
3. USGS Finds Sea Otters At Risk From Killer Whales In A Changing Ocean
4. French Researchers Breed Flightless Ladybirds As Pest-Killers
5. University Of Kentucky Researcher Awarded MERIT Extension For Study Of Third World Killer
6. How A Common Protein Becomes A Cancer Killer
7. Weevils Wipe Out Killer Weeds In Papua New Guinea
8. Virginia Tech Scientists Study Killer Molecules
9. Whales, seals or men? Who stole all the fish?
10. Whales get the bends
11. Whales drawn to waters off Mississippi River Delta

Post Your Comments:
(Date:11/12/2014)... Fla. , Nov. 12, 2014 Crossmatch™, ... today that its U.are.U ® fingerprint readers have ... chain in Central Mexico . The ... 2014 to eliminate payroll issues caused by employees clocking ... installing the U.are.U fingerprint readers, Montparnasse relied on paper ...
(Date:11/7/2014)... 2014  In conjunction with the Glendale ... Community Foundation of the Verdugos has announced the " ... a $250,000 initiative to keep the Verdugo Regional Crime Lab ... six months of existence, the Lab has processed more than ... law enforcement. "Because our number one priority is ...
(Date:11/6/2014)... that predator runs so fast that it essentially blinds itself. ... fastest creature on Earth. Some of these half-inch-long beetles cover ... per hour). The fastest human can do about five body ... a person would have to hit 480 miles per hour. ... speeds, everything becomes a blur. They can,t gather enough light ...
Breaking Biology News(10 mins):Montparnasse Pasteleria Achieves Time and Attendance Transparency with Crossmatch U.are.U Fingerprint Readers 2Community Foundation Of The Verdugos Unveils Campaign To Fund Glendale-Burbank DNA Justice Project 2The tiger beetle: Too fast to see 2
(Date:11/26/2014)... ADDISON, TX (PRWEB) November 25, 2014 ... age-defying skincare products, earned three prestigious MarCom Awards for ... , Nerium received a Platinum MarCom Award, the organization’s ... Real Event in St. Louis held in April of ... for more than 14,000 attendees. Additionally, Nerium was awarded ...
(Date:11/26/2014)... 26, 2014 CURE™ magazine ... on December 5, 2014, in San Francisco prior to ... Heroes event will honor clinicians, caregivers, and advocates who ... neoplasms (MPNs). , Special guest speaker Charles Esten, ... cancer journey at the reception. Over a decade ...
(Date:11/26/2014)... Nov. 25, 2014  Roka Bioscience, Inc. (NASDAQ: ... testing solutions for the detection of foodborne pathogens, today announced ... Piper Jaffray  26 th Annual Healthcare Conference on December ... at The New York Palace in New York, ... information concerning the Company, its operations, strategies and prospects may ...
(Date:11/24/2014)... , November 24, 2014   ... online on ScienceDirect   Elsevier , a ... services, is pleased to announce the launch of the latest ... Current Opinion in Food Science . ... will provide specialists with a new platform to keep up-to-date ...
Breaking Biology Technology:Nerium International™ Wins One Platinum, Two Gold MarCom Awards 2CURE Magazine and Incyte to Honor MPN Heroes 2CURE Magazine and Incyte to Honor MPN Heroes 3CURE Magazine and Incyte to Honor MPN Heroes 4Roka Bioscience to Present at the Piper Jaffray Healthcare Conference 2Elsevier Announces Launch of New Journal: Current Opinion in Food Science 2Elsevier Announces Launch of New Journal: Current Opinion in Food Science 3
Cached News: