Icy Killers Once a year, one of nature’s great spectacles takes place on the northernmost coast of the Gulf of Alaska. It’s a collision of two massive migrations, when thousands of ravenous salmon sharks gather to attack millions of Pacific salmon. The salmon are desperately trying to reach their spawning grounds in Prince William Sound. In a matter of weeks, the sharks will eat up to 25% of the salmon. This shark is the only one equipped to ply these icy waters.