it was not comfortable , as temeraire 's control was not very precise and he bobbed up and down wildly , but it proved very practical , for as he scattered bits of entrails onto the ocean below , other fish began to rise to the surface to feed on the discards , and when he had finished with the porpoise he at once snatched up two large tunnys , one in each forehand , and ate these as well , and then an immense swordfish also .