Bluefin tuna rule the ocean as some of the biggest fish targeted on rod and reel.
Anglers travel thousands of miles to prime bluefin spots or spend days aboard long-range boats just for a chance to battle the largest of the tunas. Bluefin are wide-ranging, voracious and strong, requiring anglers to equip themselves with the latest tools to find them and some of the stoutest conventional tackle available to land them. While bluefin compete in size with some of the largest billfish, in battle they don't waste energy jumping around for the camera, but rather put all of their effort into pulling line off reels.
Bluefin tuna are divided into two groupings, the Atlantic bluefin (Thunnus thynnus) and Pacific bluefin (Thunnus orientalis). These highly migratory fish school by size, with the largest giants making the longest journeys. Throughout their range, bluefin tend to favor deep ocean waters in the winter, while traveling along seasonal migration routes in spring and summer.
Atlantic bluefin are found on both sides of the ocean from Newfoundland south to Brazil and Peru in the west and from Norway to Africa in the east. They also venture into the Mediterranean and southern portion of the Black Sea.
Pacific bluefin primarily spawn in the waters near Japan. From there they often travel incredible distances, with juvenile fish being commonly caught off Southern California and Baja Mexico. Adult fish will often frequent waters much further south.
Bluefin seasonally run close to shore in a number of legendary hotspots worldwide. The Atlantic bluefin's annual appearance in Bimini's Tuna Alley was once the stuff of legend, where in the 1950s crews employed spotter planes to run down massive schools of big bluefin (see video in gallery above). The numbers of trophy fish coming out of the Bahamas dwindled from historic highs, but the occasional 1,000-pounder is still pulled from these waters.
More recently, the Atlantic coast of Canada has again become the go-to spot for a good shot at a giant bluefin over the magical 1,000-pound mark. It's no secret that the biggest bluefin prowl the waters off Novia Scotia --Ken Fraser landed the 1,496-pound all-tackle world record here in 1979 -- but recent reports have noted the return of historic numbers of big fish to Nova Scotia in recent years.
Anglers targeting big Pacific bluefin should make their way to New Zealand, where a number of world-record fish have been landed recently, including the current all-tackle world record of 716 pounds, 8 ounces. While bluefin were once thought to stay well above the equator, researchers and fishermen have found that adults visit New Zealand and Australia with regularity.
Bluefin tuna are heavily built for speed and power. They sport deep blue coloration on their backs, fading into light gray on their bellies. The bluefin's anal fin and finlets are yellow with a black edge, and the lateral keel is black in adults.
Other than their immense size, the main identifying characteristic that can be used to separate bluefin from other tunas is their short pectoral fin, which extends to the 11th or 12th spine in the bluefin's dorsal fin. Other tuna, especially albacore and yellowfin, sport much longer pectorals.
Fascinated by the bluefin's ability to easily swim between areas of warm and cold water, scientists have discovered that bluefin tuna sport a highly evolved heat-exchange system. Bluefin can change their heat conductivity at will, reducing body heat loss in cold water and giving them an advantage over prey.
Bluefin are effective and voracious predators, and target prey by sight before overtaking them with lightning-fast speed. Bluefin feed on a variety of schooling fishes, squid and crustaceans.
Some scientist believe that bluefin can live to 40 years old in the western Altlantic. While they grow quickly as juveniles, their growth slows in adulthood, taking 10 years for a fish to reach two thirds of its maximum length. Bluefin can lay up to 25 million eggs during a summer spawn, but despite this fecundity all species are highly endangered due to overfishing.
Up until the 1950s, many unwanted bluefin landed by recreational fishermen would be ground up into cat food or meet other unceremonious ends. But the growing sushi craze would eventually make bluefin tuna some of the most valuable fish in in the sea, with individual fish now often selling for sometimes obscene prices. In January of 2013, for example, a single 489-pound bluefin sold at the Tsukiji fish market in Japan for a record $1.76 million, albeit as part of an annual publicity stunt.
Such rabid demand has led to exploitation of the bluefin tuna worldwide. Some researchers estimate Atlantic bluefin numbers dropped over 90% from historical highs due to overfishing, creating a need for strict conservation. But bluefin travel great distances across national jurisdictions during their life, complicating conservation efforts.
Once thought to be completely separate populations, researchers have discovered that eastern and western Atlantic bluefin populations regularly mix. And while authorities in the west might set strict limits on commercial and recreational anglers, rampant overfishing in the eastern Atlantic and Mediterranean has impacted numbers on both sides of the Atlantic. The key to the species survival is international cooperation.
The International Commission for the Conservation of Atlantic Tunas (ICCAT) was formed in 1969, and tasked to study tuna, their habitats and fishing pressures throughout the Atlantic, and work with member countries to set sustainable fishing quotas and ensure responsible harvest. ICCAT constantly faces political pressures, however, and the organization has come under fire from a number of conservation groups regarding its quotas and policies. The battle is not over for the mighty bluefin.