I dug up some more info after speaking to my husband.
I found this gem:
Most parasites which are fully grown into worms are visible and obvious. Fishes that contain these do not even make it to the fish market. The parasites that are of concern, if any, are the tiny larvae and the young parasites that are present in bonito and salmon. The tentacularia is found in a low percentage of bonito, and the anisakis is found in a very few salmon since it lives in fresh water during mating season. The existence of these parasites were known for a long time. The bonito has a lesser chance of having parasites which have a characteristic of living right under the skin. For this reason, the skin, along with a few millimeters of flesh underneath was always charred before it was served (tataki method). As for salmon, it was never used for sashimi or sushi until very recently.
The salmon was considered dangerous to serve for its higher chance of having parasites than bonito, and it was never eaten raw in Japan, but this was not true for the Ainu culture that lives in Northern Japan. They understood for centuries that freezing the salmon in the snow for a couple days makes it edible without any chance of stomach problems. Recent scientific studies concluded that all parasites linked to sushi can be killed off by freezing it at a temperature of -20 degrees Celsius (-4 degrees Fahrenheit) for 24 hours. Nothing tastes better than a pre-frozen fresh sashimi, but freeze treatment is often used on other fishes used for sashimi and sushi just to be extra safe about parasites. The good news is that most seafood have to be freezed anyways when they are transported. The question to ask is at what temperature and how long.
SO... I'm going to the grocery store.. and buying 2 lbs of spicy ahi and putting it in the deep freeze! TONIGHT!