The wreckage of a 379-ton tuna boat blocks the road to the deserted fish market in Kesennuma, once Japan's largest port for bonito and swordfish. Even after the debris from last month's tsunami have been cleared away, the industry may never recover.

"Thirty years ago we used to think Japan was the No. 1 fishing country in the world, with the best catching and processing methods, but that's really no longer the case," Ryosuke Sato, chairman of the Kesennuma Fisheries Cooperative Association, said in an interview in the town "We've been in terminal decline."

Traffic at the port had dropped by 90 percent over the last 20 years as seafood imports rose, even before the Tohoku region coast was devastated on March 11. Destruction of boats, harbors and processing plants, coupled with fears of radioactive contamination in marine life, threatens to hasten Japan's turn to overseas for its most important food staple after rice.