Tuna are powerful, fast-swimming fish found in oceans worldwide. Their size varies considerably across species, with some being relatively small and others ranking among the largest bony fish. Their weight is significantly influenced by species characteristics, environmental conditions, and biological factors.
Average Weights by Species
Atlantic bluefin tuna are among the largest, with mature adults typically weighing between 496 and 551 pounds (225-250 kg) and measuring 6.6 to 8.2 feet (2-2.5 meters) in length. They can reach a maximum weight of up to 1,500 pounds (680 kg). Yellowfin tuna commonly weigh around 80 pounds but can occasionally reach 200 pounds, with a maximum size of about 400 pounds (181 kg).
Bigeye tuna can reach up to 600 pounds (270 kg), with common catches ranging from 20 to 200 pounds. Albacore tuna are smaller, with an average market weight between 10 and 30 pounds, though they can grow up to 100 pounds (45 kg). Skipjack tuna are comparatively smaller, commonly weighing 18 to 22 pounds (8-10 kg) and reaching a maximum of 76 pounds (34.5 kg).
Factors Influencing Tuna Weight
Several factors influence a tuna’s weight, including age, diet, habitat, and water temperature. Tuna exhibit rapid growth, especially in their early years, with weight increasing significantly as they mature. For instance, Atlantic bluefin tuna can grow from microscopic larvae to sexually mature individuals weighing hundreds of pounds within a few years. Growth rates slow with age, though some very large specimens can be up to 50 years old.
Diet and prey availability are important for tuna growth. Tuna are apex predators, and their diet changes as they grow, consuming zooplankton as larvae and progressing to larger fish, squid, and crustaceans as adults. Adequate food supply supports their rapid growth. Water temperature also plays a significant role. Tuna are sensitive to temperature changes, which affect their distribution, migration, eating habits, and growth rates. While some species, like skipjack, thrive in warmer surface waters, others, such as Atlantic bluefin, prefer cooler temperatures. Shifts can force them to move, impacting feeding opportunities.
Record-Setting Tuna Catches
Record-setting catches highlight the immense size some tuna can attain. The all-tackle world record for Atlantic bluefin tuna stands at 1,496 pounds (678.5 kg), caught by Ken Fraser off Nova Scotia, Canada, in 1979. For Pacific bluefin tuna, the record is 907 pounds, 6 ounces (411.5 kg), landed by Donna Pascoe in 2014 off New Zealand.
The largest yellowfin tuna on record weighed 427 pounds (193.68 kg), caught by Guy Yocom off Cabo San Lucas, Mexico, in 2012. The record for skipjack tuna is 46 pounds, 5 ounces (20.9 kg), caught in 2020 off La Gomera, Spain. An 88-pound, 2-ounce (39.9 kg) albacore tuna, caught by Siegfried Dickemann off Gran Canaria, Spain, in 1977, holds the world record for that species. For bigeye tuna, the Atlantic record is 392 pounds, 6 ounces (177.9 kg), caught in 1996 off Gran Canaria, Spain, while the Pacific record is 435 pounds (197.3 kg), caught in 1957 off Cabo Blanco, Peru.