Marine biologist Dr. James Estes researched sea
otters and their habitats in the Aleutian Islands of the
North Pacific Ocean. Sea otters feed on animals such
as crabs and urchins. Islands with sea otters
contained a lot of kelp, a seaweed that is an important
food source for fish and other sea animals. However,
Islands without otters had large populations of urchins
but no kelp since sea urchins feed on this seaweed.
Since sea otters are able to control the population of
urchins, this allows for kelp to freely grow in those
areas. Given this information, what term best
describes the otter in the Aleutian Islands ecosystem?
(1 point)
decomposer
keystone species
producer
apex predator