How Tuna Is Caught and Processed
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How Tuna is Caught and Processed
Hailing from the cold waters of our oceans is the tuna fish, coming in over 50 different varieties and sizes. Prized for their fighting abilities and meat, the most sought-after tuna fish are the yellow fin tuna, big eye tuna, blue fin tuna, albacore tuna, and the skipjack tuna. Unlike most fish, that have white meat, tuna possess a pinkish to deep red meat. The coloration comes from the oxygen-binding molecule, myoglobin. Some larger tuna fish, like the blue fin tuna, express various warm-blooded adaptations. They are able to raise their core temperature well above the water temperature through muscular-activity. This allows them to survive cold temperatures and have a wider-spread range of ocean environment, something most other fish cant do! The larger species also have the growth range of up to 300 pounds, meaning if someone decided to go deep sea fishing and hooked one of these monsters, theyre going to have a “reely” long fight!
The tuna fish is also known for its unique trait of being able to fold in its pectoral and dorsal fins to reduce drag, adding more speed to the already streamlined and fast fish. The shape of their bodies also had an influence in the shape of torpedoes, because they were so streamline. Being iridescent and shimmering in color, the tuna is camouflaged with its upper body being a metallic blue and under its body being silver-white. This camouflage and speed they have not only helps them evade predators but to catch their unwary prey. The voracious appetite that these fish have contribute to the 6.5 feet nearing length and 550 pound weight they can achieve, larger ones not being uncommon. Tuna normally eat smaller fish, crustaceans, squid (which move exceptionally fast), and eels.
The migratory habits of the tuna fish are also quite interesting, due to the fact that they are warm-blooded. This fish can survive in very cold waters off the coast of Iceland and Newfoundland. The tuna heightens its core temperature through constantly swimming, which causes the muscles to move back and forth causing heat. In warmer areas like in the Gulf of Mexico and the Mediterranean sea, the fish is still comfortable because it is able to regulate its temperature, not as specifically as mammals but enough to keep the fish at a stable condition. These warmer waters are also where all tuna fish migrate to breed. Not much is known about their migratory behavior but they may stay in a feeding area for 3-4 years and when breeding season comes, they all make a bee-line for their breeding grounds in the Mediterranean and Gulf of Mexico.
The sweet, succulent flesh of the tuna fish is highly prized by many peoples, mostly sashimi eaters, who eat the raw flesh of fish. Many countries have found a common interest, and that was to catch as many tuna as they could! Japan, having the largest fish market in the world, caught 12,000 to 20,000 tons of southern Bluefin tuna, 6,000 over the agreed amount limit the rest of the world issued. Not only do these 6,000 tons of tuna cost about two billion U.S. dollars, it greatly depleted the amount of the southern Bluefin tuna in the ocean surrounding Japan. Along with Japans appetite for tuna not being fulfilled ever again, they nearly brought the tuna stock to commercial extinction. Japan also pulled a move where they tried to pin it on Australia saying that the Australians did not report all of their tuna catch, stating that they had much more tuna than they had reported to the officials.
The relationships that schools of tuna have with other animals, such as dolphins, have been taken advantage of. When commercial fishers go out to fish for tuna, they search for pods of dolphins and drop their nets. Most of the dolphins that get entangled in the nets are inevitably injured or killed. The dolphins swim by the tuna to protect them from sharks; the tuna just associate themselves with the dolphins for greater protection from sharks, one of the few tunas predators. The people who commercially fish for whales have used tuna as their excuse saying that hunting for whales is a great way to improve tuna stocks. The act of making catching the tuna more “dolphin-friendly” has caused the nets to by catch other marine life including sharks, sea turtles, and other oceanic fish which get killed when entangled in the nets. From there albacore, bigeye tuna, blackfin tuna, pacific Bluefin tuna, northern Bluefin tuna, southern Bluefin tuna, and the yellowfin tuna have all been added to Greenpeace Internationals red list in 2010. And the thing is that the tuna that makes up 60 percent of all tuna stock in the ocean, the skipjack tuna, is nowhere near being overfished. This statistic suggests that countries that commercially fish for tuna ignore the smaller more abundant species but instead go for the larger and scarcer tuna.
The methods of catching tuna is not limited to but includes a traditional style of a network of nets, fish farming, longline fishing, purse seine nets,