Mackarel Scad or Ōpelu are black metallic to blue green and are silvery white along the belly. Their tails are yellow-green and have a small black spot on its operculum, or gill plate. ‘Ōpelu resembles a mackerel with a long and slender body, similar to that of Akule, but more elongated. It has a sweet, oily flavor similar to mackerel and is great for grilling.