If there’s blood in the water does a circle of grinning sharks give a tooth that the beefy bluefin tuna is loaded with mercury and disappearing from the oceans? Hell no. And neither did the mob of grinning, camera-wielding shoppers that surrounded a 300-pound Mediterranean-caught leviathan at the “Giant Bluefin Tuna Cutting Performance” yesterday at Mitsuwa.

I was feeling pretty good watching it all go down. “Only children can touch big tuna!” shouted a woman in a bandanna as she and her cohort urged little kids to bum rush the barriers and stroke the glistening fish. Their parents snapped away. We were told the fish was about six or seven years old and about half its potential size. A master of ceremonies earned some yuks by unveiling a plastic samurai sword and attempting to cut away one of its pectoral fins. Then out came the hacksaws and a long, much sharper blade and a three-man crew got to work, taking off the head and breaking down the first half of the loins and the belly.

The emcee auctioned off the massive head. A kid perched atop his dad’s shoulders bid furiously for it, winning it for $15–they were planning to make soup. The collar went for $35. Very quickly the Mitsuwa crew portioned, wrapped, and tagged the lean akami, or loin at ($39.99 a pound) but many in this crowd were waiting for the otoro, the superfatty, melt-in-your-mouth underside of the belly. Even with the price at $62 a pound, people clustered at the scale. Some had strategically positioned their kids in front, and the little monsters reached up to snatch the packages the instant they were weighed and priced.

Standing by the display cooler where they were supposed to go, I waited with increasing anxiety as three beautifully marbled rectangles were intercepted by well dressed, middle-aged women with murder in their eyes–all of whom had already collected four or five pieces. But I did eventually score a nice little piece for $13 and change. I also splurged on some fresh wasabi root and a piece of yellowtail.

No one, it seemed–myself included–wanted to wait for the second half of the belly to be cut. After I’d gone over to the food court for lunch, the crowd dispersed and there was plenty to be had.

I booked home only to be confronted by this grim New York Times piece by Mark Bittman about the depletion of the world’s wild fisheries. A bluefin ain’t a mulefoot. These fish aren’t coming back if we keep eating them the way we do.

My precious, hard-won little piece of tuna belly now made me feel like a jerk driving a Hummer around a golf course.