Japanese grocery w/ Bonito?
Your "even those in Metairie" line made me chuckle. The best ethnic shopping in our area is all in the suburbs. The best Japanese centric supermarket in these parts is Asian Gourmet Market, 3239 Williams, in Kenner. It isn't a huge store, but it has more Japanese items than the larger Hong Kong Market. If AGM doesn't have whole bonito, I'm sure it can be ordered for you. I've never looked for it, so I can't say if it is a stock item or not.