Patch reefs are isolated, relatively small growths of coral that typically occur on the bottoms of near-shore shallows around Key West. The majority of the patch reefs lie across the Hawk Channel and just inshore of the main living coral barrier reef that extends along the southern edge of the Keys. They are usually circular in shape and set amidst sand or sea grass flats. Patch reefs offer shelter and habitat to many fish, with several species mingling on a given reef. There are thousands of patch reefs, and they make great fishing spots during the winter and good sites for snorkeling and diving in the summer.