double-lined mackerel
A species of mackerel (Grammatorcynus bilineatus) found in tropical waters. The name is usually written in kana.
In Okinawa, double-lined mackerel can sometimes be caught.
Katakana spelling, common for fish names in biological or culinary contexts.
The name likely derives from the two dark lines along the body (二条) and the mackerel family (鯖). The exact origin is uncertain.