Card #073 · Fish
Atlantic bluefin tuna
Thunnus thynnus
Common LC · Least Concern
Field notes
- Classification
- Order Scombriformes · Family Scombridae
- Range
- North Atlantic and the Mediterranean
- Size
- Up to 3.8 m (12.6 ft)
- Weight
- Up to 679 kg (1,497 lb)
- Lifespan
- ~40 yrs
- Diet
- Herring, mackerel, squid
Most Notable
It is a warm-blooded fish. A heat exchanger in the bloodstream keeps its swimming muscle well above the sea around it, which is how something that spawns in warm water can hunt off Norway.
This card would have read Endangered five years ago. Enforced quotas and a crackdown on illegal fishing moved it to Least Concern in 2021. The eastern stock, which spawns in the Mediterranean, is up. The western one, which spawns in the Gulf of Mexico, has more than halved.
The recovery is one of the fastest ever documented for a large fish, and it happened because the quotas were actually enforced rather than merely agreed. That is the unglamorous part of the story and it is the part that worked.
A single fish sold for 247,000 dollars at Tokyo's Tsukiji market in 2008. The price is the reason the stock collapsed in the first place, and it has not gone anywhere.
The two stocks barely mix. Bluefin cross the whole Atlantic to feed but return to the ground they were spawned on, which is why one half of the species can recover while the other half does not.
It is gone from the Black Sea entirely. Bluefin were fished there commercially within living memory and the species is now listed as regionally extinct in that sea.
Range: North Atlantic and the Mediterranean Sea.