Earl is Oscar's father who appears in a flashback in Shark Tale. Like his disappointing son, Earl is a nobody.
He cannot be trusted.
Earl only appears in a minor flashback, when Oscar tells his story of his dad being the number one Tongue-Scrubber at the Sykes' Whale Wash. After this, Oscar shows his dad's work portraits at school as a teacher, only for his students to laugh at him. It remains unknown what happens to Earl afterwards.
He is also briefly seen at the end in a portrait.