Tuna is a different to brine. For the most part because of the high fat content it needs to be brined longer. WAY LONGER.
Where did you get your fat content numbers from Birdsnest? From what I can tell most tuna has a very low fat content. Salmon has 5-6 times more fat.
http://www.diffen.com/difference/Salmon_vs_Tuna
Not disagreeing with your long brine conclusion just on the reason it works.
Here's a raw recipe I've been making with Spanish mackerel but I think it would go well with albacore or even Pacific mackerel. If you're making it from fresh tuna you can even use a spoon to scrape out the meat between the bones after the fillets have been removed and really max your meat yield..
Mackemole:
Adapted from:
http://tworedbowls.com/2013/06/17/ha...picy-ahi-poke/
It's a Hawaiian take on fish tartar / spicy tuna
Mackemole
1 lb Spanish mackerel (or tuna) filets with skin and dark meat removed
1-2 Avocadoes
about 1 tbsp soy sauce, to taste
about 1 tbsp sesame oil, to taste
2 scallions, chopped finely
2 tbsp mayonnaise or
1 tbsp Sriracha (or other hot) sauce (adjust depending on how spicy you like it)*
1/2 tbsp lemon juice
Cut mackerel and avocado into 1/4" cubes or whatever size you like to eat. Mix the rest of the ingredients together in a non metallic bowl and then fold in the mackerel and avocado. Chill in fridge for 30 mins and devour with chips, over rice or make handrolls with some dried seaweed, some sushi rice and the mackemole.