Thousands of seals have congregated on Cape Cod. But now the seals are attracting sharks, and some fishermen say the seals are eating all the fish. Sharks are drawn to big seal population, flocking here. These fascinating pictures taken by Welsh-born photograph Dan Callister capture the daily battle for life in the waters around Seal Island. (Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)

(Source: huanqiu.com)