Not sure what the Tuna is that we get at the supermarkets, but it's not as nice as it was when I was a kid, as there are a number of different "Tuna" in Oz waters, and the Blue Fin that we were educated on as children won't ever make it to the table in Oz.
(Colin Thielle wrote a book, that became a movie called Blue Fin, at the height of average joes making money from fishing. Good book/movie, Perfect Storm ripped some of it off)
Southern Blue Fin Tuna is currently listed as endangered, peak Tuna having occured in 1982, and stocks being down 90+ percent since then.
Some people (same people who blame depletion on whales, and justify hunting them in Oz waters to preserve fish stocks) still fish for them, and their scarecty reflects what the Japanes are willing to pay, $1,000 per fish...the other week one bloke paid nearly $3/4M for one fish.
[/rant]
It's tasty, but we can usually only get salmon (don't mean "only", more "just").
Boss puts some olive oil salt and pepper on a sheet of foil, tops with shredded shallots, grated ginger, shredded carrot, a little soy, and a little fish sauce, seals the foil, and 15 mins in the oven...it's lovely.
There's a Company in Oz (Cleanseas Tuna), that have successfully spawned Southern Bluefin, and raised them to fingerling status on a couple of occasions...Awesome if they can pull this off.