THE ANIMAL FILES

Yellowfin tuna

Thunnus albacares

Bright yellow fins mark a predator that can also become prey.

Yellowfin tuna are fast-moving ocean predators, but their role changes as they grow. Small fish can be eaten by larger hunters, including other tuna, while large individuals take their own varied prey. Their yellow fins, schooling companions and use of depth show why an open-ocean life still has many different settings.[1]

Follow the evidence ↓
Yellowfin tuna
Image: OAR/National Undersea Research Program (NURP) · Commons · Public domain
Bright structures
Yellow second dorsal fin, anal fin and finlets[1]
Companions
Often fish of similar size[1]
Food
Fish, squid and pelagic crustaceans[1]

The yellow is in particular places

The second dorsal fin, anal fin and small finlets near the tail provide the yellow that gives the species its name. Mature fish can develop long, curved second dorsal and anal fins.[1]

A surface-water fish can still dive

Yellowfin often use the ocean’s upper mixed layer, but tracking records show that individuals can make much deeper dives. A typical habitat and an occasional excursion are different kinds of description.[1]

Size changes the food-web position

Schools often include similarly sized fish and can contain more than one tuna species. Yellowfin eat fishes, squid and oceanic crustaceans, while juveniles are themselves taken by larger predators.[1]

A COMMON MIX-UP

Does being a predator mean yellowfin tuna have no predators?

No. Young yellowfin are eaten by larger fishes and other ocean hunters. Predator and prey describe a relationship between particular animals, not permanent opposing categories that a species can never cross.[1]

TRY A LITTLE REASONING

Why record both depth and time spent there?

Reveal the explanation

A rare deep dive does not show that the animal normally occupies that depth. Tracking both the excursion and the usual depth distribution helps distinguish exceptional movements from the water layers used most often.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Yellowfin tuna (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Thunnus albacares (identity and classification)

Last fact check:

One discovery leads to another

Atlantic mackerelA mackerel school can change formation when the prey changes.Scomber scombrus ↗Blue mackerelA streamlined hunter with a surprisingly broad small-prey menu.Scomber australasicus ↗Allmouth goosefishThe fishing rod is part of the fish.Lophius piscatorius ↗