Part 1
possible causes
*sea otters spend 48 percent of the daylight hours grooming and cleaning their fur. This is the reason oil spills are so dangerous to sea otters. The oil coats the guard hairs and, since oil cannot be easily removed, the underfur becomes wet, loosing its insulative qualities, and the animal dies of hypothermia.
Part 2
What predator is decreasing them
*increased predation by killer whales was the cause of the sea otter decline
What expirments could you use to tell
*know all about habits and reasreach of the killer whale, what it eats sleeps reprodeces etc.
*estimated the impact of killer whales on sea otter populations by comparing trends in population size and survival rates of individually marked otters between two adjacent locations on Adak Island-Clam Lagoon and Kuluk Bay. Kuluk Bay is on an open coast, so sea otters there are exposed to killer whales.
Could killer whales be it?
*If increased predation by killer whales was the primary cause of the sea otter decline in Alaska from 1990-1996, as Estes and his group suspected, killer whales would have to have eaten 40,000 sea otters in six years
Part 3
Why are killer whales eating otters?
*All the evidence collected by Estes and his coworkers points to killer whales as the cause of the decline in sea otters: the increase in observed killer whale attacks on sea otters, the differences in sea otter survival and population trends at the two locations on Adak Island
Part 4
Who cares?
*Although sea otters formerly were found at all of these locations, they were exterminated from most of their range by hunting during the 19th century. Amchitka and Adak Islands in the Aleutians were locations of some of the few remnant populations at the time otters were protected in the early 1900s. Sea otters were re-introduced to southeast Alaska in 1968-71. That population expanded into Surge Bay by the early 1970s and into Torch Bay in 1985.
