Overfishing now threatens one of the most popular items on U-S menus; swordfish. That’s according to Carl Safina, a research ecologist and founder of the Living Oceans Program for Marine Conservation at the National Audubon Society. He’s just written a book about fish and fishing called “Song For the Blue Ocean: Encounters Along the World’s Coasts and Beneath the Seas” being published by Henry Holt and Company. Steve Curwood spoke with Dr. Safina who says part of the reason for the swordfish decline is the way the fish are caught.