Bluefin Tuna are among the largest and fastest fish in the sea. With bodies built like torpedoes and retractable fins, they are able to dive deeper than 300 feet. They also have the best vision of any bony fish in the ocean, and from the moment they are born, they use their incredible sight to hunt for schools of fish such as herring, mackerel, and eel.
There are three main types of Bluefin: the Atlantic, Pacific, and Southern. The Atlantic bluefin tuna is the largest and most endangered tuna. They are able to live up to 15 years in the wild and grow up to 9-ft long. They can weigh up to 1,200 lbs. The picture to the left was taken by Don Vipirino of Osprey Sportfishing in Rock Harbor, Orleans. Chris Pavlakis and Cam Vipirino caught this 710-lb ‘butterball’ this past Tuesday.
Atlantic bluefin bodies are metallic blue on top and silver-white on the bottom. Their coloring helps them to camouflage from above and below. They are warm-blooded creatures and can live in both cold and tropical waters, though they spawn in the warmer waters.
These tuna are among the most ambitious migrators of all fish. They can swim up to 43 miles an hour and will put up quite a fight when hooked on the fishing line. They eat smaller fish, crustaceans, squid, and eels, and also filter-feed on zooplankton and other small organisms.
Because of the high demand for Atlantic bluefin tuna in Japan especially, the fish stocks are plummeting. There are now international conservation efforts taking place to rebound the population.
The Pacific bluefin tuna can grow up to 10-ft long and weigh over half a ton. They are also amongst the world's largest fish and are in demand for their meat on the seafood market. They can also travel thousands of miles to cross the Pacific Ocean to spawn in 53 days or more. They can travel through icy waters and dive up to 1800-ft down.
Bluefin's blood temperature can be warmer than the water. This can help them swim much faster and more powerfully because of this metabolic process. Between April through August, they spawn in the western Pacific ocean between Japan and the Philippines. When they are about a year old, some of them migrate over 5,000 miles to the eastern Pacific near Baja California, Mexico. They will stay there for a few years and then return to their spawning grounds in the western Pacific. It is in this area that the bluefin tuna population is experiencing the most overfishing. Their numbers are now at approximately 3% of historical, pre-fishing levels, and they are listed as “vulnerable” by the International Union for the Conservation of Nature and Natural Resources. Conservation efforts are being taken worldwide to reduce and regulate catch levels. We can do our part by not eating this kind of tuna. Not to worrry, though, there are many other kinds of tuna to eat!
The Southern Bluefin Tuna is a large pelagic species that can live between 20 and 40 years. They are commonly caught by Indonesia and Japanese commercial long-liners in the Indian ocean, where they also spawn. They can grow up to 2.45 meters and weigh up to 260 kg. They have swim bladders, which help them to stay afloat, and are silver-white on their underside. Their first dorsal fin is yellow or blue, their anal fins and finlets are a light yellow with some black detail. They have lines and rows of colorless dots on their body. They typically will eat fish, crustaceans, cephalopods (octopi, squid), and other creatures. According to the IUCN, the southern bluefin is listed as critically endangered.
This past summer, I became captivated by the National Geographic show Wicked Tuna. I never realized how incredible these creatures are, and the extent of how much their populations are suffering worldwide. I think that while this show has brought more awareness to the plummeting population, it also glamorizes fishermen making a living off emptying the oceans of these creatures, which is dangerous to the ocean populations. It’s great to teach people that tuna fish are more than just a can in the supermarket, but it’s even more important to protect these creatures from overfishing and extinction.
Cover photo- Monterey Bay Aquarium
2nd photo- Osprey Sportfishing, Orleans
3rd photo- PEW trusts
NatGeo, Monterey Bay Aquarium, Marinebio.org