Skeletal changes in the test and jaws of the sea urchinDiadema antillarum in response to food limitation

A comparison of western Aleutian Islands with and without sea otter populations shows that this species is important in determining littoral and sublittoral community structure. Sea otters control herbivorous invertebrate populations. Removal of sea otters causes increased herbivory and ultimately results in the destruction of macrophyte associations. The observations suggest that sea otter reestablishment indirectly affects island fauna associated with macrophyte primary productivity.