Not quite Portuguese, but the Osaka style sushi’s boxed mackerel is named after the Potuguese word “bateria”, or small boat. The name evolved into the word battera, and is used commonly in Japan today.The word battera was derived by an Osaka sushi restaurant around 1893 to describe a gizzard shad sushi, which looked like a small boat, and eventually became a word just for boxed cured mackerel.
The battera uses one fillet of a mackerel and is placed inside a mold (sushi box, or hakozushigata) filled with sushi rice. A piece of vinegared kelp is placed on top, and pressed with the lid of the sushi box. They are cut in individual pieces and result in rectangular boxes.