Continuity mistake: The boulder that Mickey throws at the seagull was not on the big rock when he first started chasing the bird.
Continuity mistake: When Mickey is fishing, there is initially a bucket behind him. When we see Mickey fishing later on, his hat appears from nowhere.
Continuity mistake: When Mickey is about to put the hook through the fish, you can see in a long shot that Mickey's hand is above the fish, holding the hook. However, in a close-up of the fish, Mickey's hand is nowhere to be seen.