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Tuna School

Species We Sell

Skipjack (Katsuwonus pelamis) – in our Light Tuna products, including our Flavoured Light Tuna and Tuna Salad Kits


Albacore (Thunnus alalunga) – in all of our White Tuna products, including our Gourmet Flavoured White Tuna line


Yellowfin (Thunnus albacares) – in our Light Yellowfin Tuna products

Images by Emma Fowler


A large, highly migratory category of fish living in oceans around the world. Streamlined for rapid swimming with retractable fins and a torpedo-shaped body. Consumes other fish, crustaceans, and mollusks. Depending on the species, can range in size from 100 cm to just over 2 m at adulthood.


How It's Fished & Processed




PURSE SEINING is a method used to catch tuna. A seine or net is drawn out from the fishing boat and around the school of tuna. Weights carry one edge of the seine deep into the water. When the fish are surrounded, the bottom of the seine is drawn together or pursed, so that the fish are trapped and hauled aboard the boat. This method accounts for about 80 percent of the commercial catch of light meat tuna. It takes 368 liters of fuel to catch one ton of tuna using the purse seine method.

All of Clover Leaf’s skipjack and yellowfin (labeled as ‘light’) tuna are fished using this method.



LONG-LINING accounts for about 80 percent of the world's albacore tuna harvest. A very long line (as much as 130 km or 81 m) supported by floats and marked with flags is set out from a fishing boat. Branch lines attached to the long line are sunk with baited hooks to depths of 55 to 150 meters. It may take as many as 20 hours to set a line, and longer to retrieve it with its catch. It takes roughly 1070 liters of fuel to catch one ton of tuna using the long-line method.

All of Clover Leaf’s albacore (labeled as ‘white’) tuna is fished using this method.

POLE AND LINE and TROLLING are other means used to catch tuna commercially. Live bait (anchovies or sardines) are dumped from the fishing boat to bring tuna into a feeding frenzy. This is called "chumming". Fishermen on the boat drop lines with barbless hooks into the school of fish, and bring them aboard as they are hooked. It takes 1485 liters of fuel to catch one ton of tuna using the pole and line method. (Not enough data is available for trolling.)



Tuna is delivered to the cannery either directly from the fishing vessel or from freezer ships delivering from foreign fishing companies. During the unloading, the fish is "sized" which keeps fish of the same size and weight together.



The cleaned loins are then moved to the canning process. Cans are automatically filled with tuna and move in a single line from the filling machine towards the vacuum sealer.


Species Information

Skipjack Tuna (Katsuwonus pelamis)

Skipjack is the smallest tuna canned. Its average size is 3 kg (6 lbs) to 5.5 kg (12 lbs). Although small, it accounts for the largest share of tuna caught and eaten by people around the world, and is the most abundant tuna species. In fact, the majority of Canadian canned tuna is packed with Skipjack. Skipjack live in warmer water temperatures, meaning they can be found around the world in the central belt of water.
Purse seining and pole & line are the most common methods of catching this tuna.

Clover Leaf catches all of our Skipjack tuna using the purse seine method and sources mainly from the Western Pacific Ocean. Skipjack tends to be darker in colour and have a fuller flavour than Albacore (white) and Yellowfin (premium light).


Albacore Tuna (Thunnus alalunga)

Albacore is the only kind of tuna allowed to be called "white meat tuna" in the Canadian market. Albacore usually range in size between 4.5 kg (10 lbs) to 23 kg (50 lbs). Most migrate across the Pacific Ocean from Japan and up the coast of North America. Albacore, however, do not swim in tight schools like other tuna species. This means commercial fishing boats generally need to work harder and longer to fill their boats. Usually, fishers need to be several hundred miles from shore to catch this long-finned tuna.

Clover Leaf’s Albacore is fished using the long line method and is sourced from the Atlantic, Pacific, and Indian Oceans. It is creamy and white with a slight pink hue, and has a mild flavour. Albacore (white tuna) is the best choice when entertaining or for meals where presentation is paramount.


Yellowfin Tuna (Thunnus albacares)

Yellowfin gets its name from the bright yellow colouration of its fins and finlets. Its body reflects the colour of most tuna - metallic dark blue on the back, yellow and silver on the belly. Historically, yellowfin was the most important commercial catch, but because of improved dolphin safe catching methods, it is now second to skipjack. Yellowfin tuna is still the largest of the tunas canned. This tuna can range in size between 13.5 kg (30 lbs) all the way up to 181 kg (400 lbs)!

Clover Leaf’s Yellowfin is caught using the purse seine method and is sourced mainly from the Western Pacific Ocean. Yellowfin is known as premium light tuna because of its slightly stronger flavour than Skipjack. It is creamy light in colour, but slightly darker than Albacore tuna.


Fish Facts

  • All of our tuna are wild-caught.
  • Tuna make up 55% of the product Clover Leaf sells, by volume.
  • Tuna must always be moving to stay alive. They breathe by swimming with their mouth open to shoot water over their gills, from which they extract oxygen. To get enough oxygen, they must swim at least one body length per second!
  • Because tuna swim so rapidly and travel such great distances, they require a large quantity of food, eating around one quarter of their body weight per day.
  • Tuna have different colours on their backs and bellies to camouflage themselves against predators. Their backs are blue to blend in with the dark, deep water beneath them, while their bellies are lighter to blend with surface waters if predators are looking up from below.
  • Although tuna migrate worldwide, they return to the same regions to lay their eggs year after year.
  • Female tuna can lay up to 6 000 000 eggs in one spawning – however, only an average of 2 of these babies will survive long enough to become an adult. Juveniles are eaten by other fish (including other tuna) or seabirds.
  • Tuna are homeothermic: they maintain a body temperature several degrees higher than the surrounding water.