Atlantic Mackerel
Scomber scombrus
Dogtooth Tuna
Gymnosarda unicolor
About
The dogtooth tuna is a fast, powerful hunter that patrols reef walls and drop-offs, often alone or in a small group. Despite the name, it isn't a true tuna at all.
Also known as: white-flesh tuna, dog-tooth tuna, peg-tooth tuna, white tuna, scaleless tuna
How to tell it apart
Its name and torpedo shape suggest a true tuna, but this fish swims constantly with its jaws open, a habit true tunas don't share. That open-mouthed swimming is the giveaway underwater.
Appearance
This fish has a streamlined, torpedo-shaped body. Its back is a brilliant blue-green, fading to silvery on the sides and whitish on the belly, with a white tip on each of the two small fins set close to the base of the tail. The lateral line, the sensory stripe running along its side, undulates strongly instead of running straight. Its mouth is large, with the upper jaw reaching back as far as the eye.
Habitat
It lives on reefs across the tropical Indo-Pacific, from East Africa to French Polynesia. Smaller fish stay closer to shallow reef areas, while larger ones patrol deep reef drop-offs, seamounts, and steep underwater walls, usually alone or in small groups.
Did you know?
Despite its name, the dogtooth tuna isn't a true tuna at all. It belongs to a different group of the same fish family, the bonitos.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.
