Estes said the killer whale theory is the only one put forth so far that can explain the disappearance of so many otters. But he says it's unlikely that as few as four whales are to blame. He believes more killer whales are eating sea otters. He's not sure exactly how many, but a science cruise in the Pribilof Islands north of the Aleutians last summer counted more than 400 killer whales. Why killer whales would target sea otters in the Aleutians is a mystery, too.
Kelp forests are large jumbles of seaweed, kelp and algae.
Some species, like laminaria, anchor themselves to the seafloor. Others float with the currents. Crabs, starfishes, sea cucumbers and urchins live at the base of the forest canopy. Species such as herring spawn by laying their eggs on kelp. The benefits of kelp forests even extend to airborne creatures.