How to Identify a Saltwater Tuna

Tuna is probably the most well-known and most consumed fish on the planet. But did you know that there are 8 common varieties of tuna in the ocean? Use these steps to learn how to identify the traits of each of the eight varieties.

Instructions

  1. Identify Albacore, Atlantic Bonito, Bigeye and Blackfin Tuna

    • 1

      Notice the extra long pectoral fins and the white outline along the tail. These features make the Albacore the easiest to identify. It is also the most well-known among the tuna family as it is the kind most frequently available in cans at the grocery store.

    • 2

      Look for the steel blue coloring on the Atlantic Bonito's back and upper sides with approximately a half-dozen stripes that run forward and downward. The lower sides are silver in color. This is important to know as this fish is often confused with the Skipjack which has similar coloring.

    • 3

      Compare the Bigeye Tuna to the Yellowfin tuna as they are often confused due to their similar appearance. Both are mostly silver in coloring with yellow fins and black lined finlets. The Bigeye's anal and dorsal fins are smaller and they have bigger eyes.

    • 4

      Watch for finlets that are uniformly dark on the Blackfin Tuna without the bright yellow usually present in other tuna. The fins may have white edges. The back of the fish is bluish black, the sides are silvery gray and the belly is milky white.

    Identify Kawakawa, Little Tunny, Pacific Bonito and Yellowfin Tuna

    • 5

      See the wavy lines over a turquoise background on the Kawakawa. Some of these fish may have dark longitude stripes on the venter, but these quickly disappear when you remove the fish from the water.

    • 6

      Note that the body of the Little Tunny is wider towards the center and tapers at both ends. The coloring is pale metallic blue on the upper half and silver on the belly. The upper back has wavy lines and there are dark spots below the pectoral fin.

    • 7

      Look at the body of the Pacific Bonito. It is cigar-shaped and compact. The coloring ranges from dark blue along the top to dusky on the sides and silvery on the bottom. There are slanted dark stripes along the back.

    • 8

      Read Step 3 in Section 1 to find the general description of the Yellowfin Tuna. They are blue and black on the back and upper sides, with yellow and silver on the belly. All fins and finlets are bright yellow.