Out of more than a dozen types of squid eaten here, the Japanese flying squid, or Todarodes pacificus, is so central to the national cuisine, it's sometimes referred to as maika, or the true squid.

But now, fluctuations in ocean temperatures and years of overfishing and lax regulatory oversight have drastically depleted populations of the translucent squid in waters around Japan. As recently as 2011, fishermen in Japan were hauling in more than 200,000 tons of flying squid a year. That number had fallen by three-quarters to 53,000 tons last year, the lowest harvest since Japan's national fisheries cooperative started keeping records more than 30 years ago. Japanese researchers say they expect catches of flying squid to be even smaller this year.

That such a ubiquitous creature could disappear has shaken a country whose identity is intertwined with fish and fishing, a nation where sushi chefs are treated like rock stars and fishermen are the heroes of countless TV shows. The shortage of flying squid, an icon of the working and middle classes, has dealt a hard blow to the livelihoods of not only fishermen, but everyone from suppliers to traders at Tokyo's famous fish market.