The Bluefin trevally is in the Jack family of fishes. Jacks can be seen patrolling the reefs in schools, or sometimes individually. They feed on smaller fish, crustaceans and other invertebrates. They can be spotted hovering over eels, octopus, or foraging goatfish in hopes of grabbing a leftover morsel. Most jacks are commonly known in Hawai‘i as ulua. Juvenile jacks (under 10 pounds) are called pāpio.
The o‘milu or Bluefin trevally are silver in color with black spots and beautiful blue fins. They are able to change colors and can get very black. They are a favorite of fishermen.
photos courtesy Sandi Strickland