How to Make Pickled Mackerel 

I’d also like to know this! I catch my own mackerel

Flash frozen, otherwise a month frozen if freshly caught. I usually just ask the fishmonger/seafood section of my grocer to give me fish still solid frozen. For still frozen fish have been flash frozen right after being caught for market.

In Japan they don't freeze it normally, the risk comes from the Anisaki parisite he mentions in the video(he makes the extra cuts in the flesh and mentions those can kill it) however it is the pickling process shown here that is largely responsible for ridding the fish of parasites. In short the fish does not need to be frozen because it is being pickled in this case. If eaten raw it is highly reccomended to get it from a skilled sushi chef who knows how to cut out the part that contains the most parasites or have it flash frozen like salmon.

Assuming the fish has been killed using the ikejime method, the fish will be fine, plus the salty environment will kill whatever may be on the fish

Assuming the fish has been killed using the ikejime method, the fish will be fine, plus the salty environment will kill whatever may be on the fish

How much “waste” is there from raising chicken, beef, pork? Much cleaner process with little waste. If you are that conservation minded, lightly salt and grill the fillets.