None. The dog is known as a ‘Retriever’ as hunters used it to retrieve game on land as well as water. It is known as a "Labrador" as it originally came from Newfoundland that is quite close to Labrador.
There are 6 types of Retrievers that are recognized by the American Kennel Club.
1 Labrador Retrievers
2 Chesapeake Bay Retrievers
3 Curly Coated Retrievers
4 Flat Coated Retrievers
5 Golden Retrievers
6 Irish Water Spaniels