There’s a reason people call tuna the “king of the sea.” In addition to weighing up to 1,500 pounds, tuna is full of good fat, protein, and vitamins, a versatile taste, and meaty. Tuna is a staple in various culinary cultures.
There are 15 different species of tuna, which are detailed below. These all belong to the Thunnini subgroup of the Scombridae family. Tuna swim throughout the world’s oceans, and they’re fast about it, too. These fish have been clocked in at 75 miles per hour.
The world drools over tuna - fresh on sushi rice, scooped out of a can, grilled over a pit. While tuna meat has never been more popular with celebrity chefs or quaint kitchens across the world, tuna, like so many sea creatures, is struggling.
Due to overfishing, some species are on the brink of extinction. While we have organizations in place to supposedly protect tuna and the waters in which they swim, these policing bodies such as ICCAT and IOTC fail to enforce protective measures. There are a lot of ways to do your part as a tuna-lover. Getting to know the different species of tuna will inform your purchasing decisions and help lead towards sweeping changes in the commercial fishing industry.
[Image by Alfred Koop from Pixabay]
This species is one of the smaller varieties of tuna. It is bullet-shaped and also has the mildest flavor. They live for about 12 years and migrate throughout all ocean waters. It is frequently sold and bought in cans.
Bigeye tuna, or Thunnus obesus, live in the warm waters of the Atlantic, Pacific, and Indian Oceans. They are a dark metallic blue color except on their bellies, which are white, and their dorsal fins which are yellow. They look very similar to yellowfin tuna. While regulations are in place to minimize bycatch and nations work together to form a plan for rebuilding, this species is below its target population level. If you can find product that is “wild-caught,” that would be the most sustainable way to eat this delicious fish.
Blackfin tuna, or Thunnus atlanticus, is the smallest species of tuna, maxing out at 100 cm in size. Their oval-shaped bodies are black with yellow tints on their fins. It feeds on smaller fish and plankton. Its habitat is coastal and offshore waters.
Native to the Atlantic Ocean and Mediterranean Sea, bluefin tuna or Thunnus thynnus, is a robust species with a large mouth. They are dark blue with yellow finlets. A female fish can produce 30 million eggs in a single lifetime. There are efforts to ban any fishing of bluefin tuna, though the United Nations has rejected these initiatives so far.
Bonito tuna - or Atlantic Bonito - reside (zoologically) in the tribe Sardini - not to be confused with sardines, of course. Closely resembling skipjack, they are a predatory, striped tuna that can be found swimming in the Mediterranean and Black seas.
Bullet tuna or Auxis rochei, lives in tropical waters. It is a slender fish with a triangle-shaped dorsal fin. It is a highly migratory species with a deep purple or almost black-colored head. They are considered a critical point in the food web, due to their abundance.
Also known as white tuna, dogtooth or Gymnosarda unicolor is a large-sized tuna. Bright blue on the back, silver on the sides, and a white belly are how observers are able to distinguish this species. They are widespread through the Indo-Pacific Ocean areas, the eastern coast of Africa, and French Polynesia. They are aggressive predators.
Identified by the botanical name Auxis thazard, this species of tuna are found in tropical waters. It is a highly migratory species with small teeth. They are preyed upon by other fish, including other types of tuna. Can be sold fresh or frozen, but are often distributed smoked, salted, or canned.
Little tunny or Euthynnus alletteratus is the most commonly found tuna fish in the Atlantic Ocean. It ranges from the eastern coast of the United States all the way down to Brazil. It moves in large schools and is highly migratory. Other common names for it include false albacore, little tuna, and bonita.
Otherwise known as northern bluefin tuna, Thunnus tonggol is slender and has pectoral fins. It is easily confused with other species of tuna. Because of its slow growth patterns, it is particularly vulnerable to overfishing.
Euthynnus affinis, or mackerel tuna will give you quite a battle at the end of the fishing line. Known as difficult to reel in, they are also called Kawa Kawa. Like other species of tuna, they produce perpetual motion while alive. This species prefers warmer waters.
Pacific Bluefin Tuna
A predatory species, Thunnus orientalis, is widely distributed throughout the Pacific Ocean, though it migrates south. It is overfished and endangered. It can grow to be over 9 feet tall, but their numbers have dropped 96.8%. Most activists argue that we should avoid eating this species entirely. It spawns in the Northwestern Philippines sea. They are the second-largest species of tuna.
Katsuwonus pelamis is a medium-sized tuna fish with, finally some good news, a stable population. It has many common names including balaya, tongkol, arctic bonito, mush mouth, and striped tuna. Males can reach up to 42 pounds. Part of why this species is considered sustainable is because the skipjack tuna’s fecundity is able to keep up with consumption. Scientists only warn of “moderate mercury levels” - which is better than a lot of fish we eat today. This tuna is especially prevalent in Japanese cuisine.
Southern Bluefin Tuna
Thunnus maccoyii swims in the world’s southern waters. They migrate long distances and are an opportunistic feeder. Because tuna swims continuously and at high speeds, they have a high need for oxygen - but oxygen levels of the water change based on temperature. Can you guess what the problem is with that? Climate crisis, and warmer oceans, means less oxygen in the water. Southern Bluefin Tuna are critically endangered.
Slender Tuna, Allothunnus fallai, is another southern swimmer. They have a blue back, white belly, and a purple-to-black head. Slender tuna schools occasionally and feeds on krill. It is more oily when eaten compared to other species of tuna. Its population is currently stable.
Also known as ahi, Yellowfin is deep pink in color when on your plate, and tornado shaped when in the water. Its botanical name is Thunnus albacares, and it is a smart choice for consumption if it is wild-caught as they are not currently overfished. They have a blue back and a yellow-to-silver belly. They can be found swimming in tropical and subtropical oceans around the world.
[Image by scottgardner from Pixabay]
Tuna and Sustainability
So how do you ethically engage with the tuna industry? It’s imperative that we ask this question of ourselves and our communities. As detailed in this ultimate guide, not all tuna species are endangered, and choosing wild-caught fish from stable species is an ethical way to eat tuna. Populations of yellowfin tuna and skipjack tuna are stable. By choosing environmentally-conscious brands, it is possible to conserve and protect the species of tuna that are endangered while still enjoying the succulent taste of (almost) everyone’s favorite fish.
Article written by Siri Undlin on November 30, 2020.
[Featured image by Kevin Phillips from Pixabay]