The Squilla or “Shako” (蝦蛄in Japanese) is a delicacy that appears on the sushi bar counters from April to Summer, although different varieties can be found in Hokkaido markets (Otaru City in particular) almost all year round.
You will discover it under names such as “Shaku” and “Gazaebi”.
They are actually caught in almost all Japanese seas, but the best are supposed to originate from Hokkaido.
Like any crustaceans, they can be eaten in many ways.
The Japanese favour the small kind with a violet back. I had the opportunity to buy some very large specimen in Otaru, and eat them just boiled and served with rice vinegar mixed with a little Japanese mustard, or in salads.
They almost disappeared from Tokyo Bay in the 1960’s but reappeared in the 1970’s. Most fishermen in the Kanto area will place them in boxes themselves to sell them directly at fish markets. The market value can vary wildly, but look for the genuine harbour markets and buy them yourself.
Naturally, they are most popular as nigiri sushi. Customers jokingly ask for “garage” (in English) as “shako” also means (different kanji, of course) “garage”!