water dog

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A dog that takes easily to the water, especially one trained for hunting waterfowl.
• noun Informal A person who feels at home in or on the water.
• noun A larval tiger salamander.

from the GNU version of the Collaborative International Dictionary of English.

• (Zoöl.) A dog accustomed to the water, or trained to retrieve waterfowl. Retrievers, waters spaniels, and Newfoundland dogs are so trained.
• (Zoöl.) The menobranchus.
• A small floating cloud, supposed to indicate rain.
• colloq. A sailor, esp. an old sailor; an old salt.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A retriever type of gun dog bred to flush and retrieve game from water.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a dog accustomed to water and usually trained to retrieve waterfowl
• noun a person who enjoys being in or on the water