Usually found on the bottom eating the sea-grass that is plentiful on the bottom of this harbour, they are frequently seen at the surface getting air for their next foray for food.
(the sea-grass; is; plentiful) (they; are seen; L:at the surface; T:Usually found on the bottom eating the sea-grass; T:frequently)
the sea-grass they
is are seen
plentiful
L:at the surface T:Usually found on the bottom eating the sea-grass T:frequently