Generally the sashimi-grade fish from Catalina is good but sometimes it can be a bit of a disappointment. The current batch had excellent toro tuna but mediocre hamachi (wild caught) and the premium uni was not particularly great for sashimi (from which I made "Uni and water cress cooked in butter and soy sauce"). After tasting the hamachi as sashimi on the first day, I made this "kelp-cured" hamachi for the next day.
The hamachi shown in the left back arranged to look like a flower and the hamachi between the cucumber and perilla leaves are kelp-cured. The toro shown on the left front was absolutely excellent and "toro aburi"トロの炙り next to it was also great.
The kelp-curing helped the hamachi lose its slight gaminess (gamey because it was not quite fresh enough), firmed up the texture and added a nice additional "umami" from the kelp. This is exactly the same as kelp-cured "amber jack" ヒラマサの昆布締め I posted before.
I sliced the hamachi on the bias relatively thin ("Sogi-Giri" そぎ切り) and placed it in one layer between two sheets of dried kelp. I had previously wiped the surface of the kelp with a moist paper towel. I then wrapped the kelp with hamachi sandwiched between the two layers in plastic wrap and placed it in the refrigerator for several hours.
Although the main reason for kelp-curing is to add more flavor to white meat fish like flounder, it worked to make a somewhat marginal sashimi palatable—good save, team..