UNDER THE SEA

 Hello ladies and gents this is the Viking telling you that today we are talking about 

INTERESTING FACTS ABOUT BLUEFIN TUNA

1. YES, THEY ARE A PREDATOR

The Bluefin Tuna will eat a wide variety of prey, but they prefer pelagic (open ocean) fishes and invertebrates that they can swallow whole.

2. THEY CAN REACH UP TO 2,000 POUNDS

This, paired with reaching lengths of nearly 15 feet, makes the Bluefin Tuna especially sought after by deep-sea fishermen. There have been specific fish that are tagged by scientists to have supposedly reached this weight, but none have been caught and recorded yet.

3. THEY START OUT AS NEARLY MICROSCOPIC LARVAE

Like many open ocean bony fishes, they begin life no more than a few millimeters long. It only takes three to five years for them to reach lengths of three feet and begin being sexually mature.

4. THEIR ONLY NATURAL PREDATORS ARE TOOTHED WHALES AND SOME OPEN-OCEAN SHARK SPECIES

Once these tuna reach their full size and maturity, they go much higher on the food chain than when they were smaller. Only something much larger, and generally further from their own natural range than usual, can take one down.

5. THEY’RE HIGHLY MIGRATORY

These migrations correspond with their spawning behavior and their food needs. There are two populations of Atlantic Bluefin Tuna, with one reproducing in the Gulf of Mexico and the other in the Mediterranean Sea.

6. THEY “BROADCAST SPAWN”

This is the most common reproductive behavior for tuna. Several females and several males release millions of eggs and sperm into the water column at the same time. This increases the likelihood that the eggs will be fertilized and decreases the chances they’ll be eaten by egg predators.

7. BLUEFIN TUNA CAN RAISE THEIR BODY TEMPERATURE

Unlike most cold-blooded fish, the Atlantic Bluefin has a specialized blood vessel structure called a countercurrent exchanger that allows them to maintain a body temperature higher than the surrounding water. This is to allow them to hunt in colder water quicker and more intelligently.

8. THEY NEED TO BE CONSTANTLY MOVING

Just like sharks, the Bluefin relies on constant water flow over their gills in order to obtain oxygen. They’ll also increase oxygen intake by swimming with their mouth open.

9. IT’S BEEN SPECULATED TO BE AN ENDANGERED SPECIES

The Atlantic Bluefin was formerly common in the Black Sea and off the coast of Brazil, but it hasn’t been observed in significant numbers in decades. This has led to scientists believing it should be classified as endangered and highly vulnerable to extinction.

10. IT’S STILL FISHED HEAVILY THROUGHOUT ITS RANGE

Despite the potential classification as endangered, fisheries managers continue to allow commercial fishing to target it. It’s a highly lucrative fish for sushi and is highly targeted by fishermen.

And as always have a chilled day from the Viking