Admittedly the Japanese were hunting tuna miles from Japan in the 18th and 19th centuries, and expanded their fleets in the s and s. Tuna, though, was not a practical fish when caught so far away from the markets, until the development of deep-freeze facilities in the midth century. In feudal times it was considered to be a very low quality fish in Japan, and the poor would not eat it. One reason for this may have been a risk of food poisoning, as tunas have high body temperatures and the warm flesh spoils easily.
Before the Second World War, the fatty meaty of tuna toro and oo-toro , now highly prized in Japan, was considered to be of very low value and often discarded. In the s, they moved further into the Indian, Pacific and Atlantic Oceans to catch tuna. Meanwhile, another great tuna industry sprang up in San Diego, California, when a sardine fisherman, Albert P Halfhill, decided to plug a seasonal sardine shortage with a local species, albacore, which was once considered a nuisance.
By weight, 5 per cent of the world's entire fish catch is tuna. Landings, though, are falling. Tuna, like almost every other fish and fishery in the world, is struggling. Ninety per cent of the world's marine megafauna have been eaten. The global tuna fleet is out of control. It catches other species with abandon, and throws away all but the tuna destined for your tin, sandwich or sushi box.
But surely, you might ask, not the tuna in my supermarket, in my store cupboard? Fishing is afflicted by the "tragedy of the commons". The fish are there, wild and free, and valuable; you just need a boat. Because tuna roam the oceans outside the mile limit for territorial waters, the fisheries are regulated by five Regional Fisheries Management Organisations. In , WWF published a damning report on the failures of these to police the main commercial species of tuna: skipjack yellowfin, Atlantic bluefin, Southern bluefin, Pacific bluefin, big-eye and albacore.
As Tuna in Trouble revealed, most of these seven species are fully exploited i. WWF says tuna fisheries face "severe and alarming tuna stock declines All species of bluefin are in trouble. Organised crime in Italy is in charge of some of the Atlantic bluefin industry and, according to Charles Clover, author of a book on over-fishing which is the subject of a new film, The End of the Line, "sleazy ministers" end up working at ICCAT.
Most big-eye and some yellowfin are in trouble; albacore is fully exploited. The one bright spot is the skipjack, a member of the mackerel family. Unlike the slow-breeding tunas, skipjack is smaller and spectacularly fecund; the "chicken of the seas" is most likely to be the tuna in your tin. What concerns marine scientists, campaigners and journalists is not just what happens to the tuna and the humans who rely on it for protein, but what tuna-fishing is doing to the rest of the marine environment.
Tuna skippers are secretive, but for his book, Clover obtained the accounts of scientific observers on the by-catch; what is unintentionally caught by fishing boats. A Russian scientist, EV Romanov, estimated what was caught by the tuna fleet in the western Indian Ocean between and The boats caught , to , tons of tuna and: 2, tons of shark, 1, tons of rainbow runners, 1, tones of dolphin fish, 1, tons of triggerfish, tons of wahoo, tons of billfish, tons of mobula and manta rays, 80 tons of mackerel scad, 25 tons of barracuda, tons of miscellaneous fish, and an unspecified number of whales and dolphins.
All thrown back into the sea — dead. Some populations, such as leatherback turtles, are being heavily damaged; pushed to the brink of extinction, even though they are not being hunted. Purse seine boats that drop giant drawstring nets in tuna areas, and "long-liners" which sink lines of up to 80km, hooked with bait, are the biggest by-catch culprits. Conservationists say pole and line fishing, where boats drops bait into the sea and fishermen claw the tuna into the boat avoiding other species , are "cleaner" methods.
In a report from Greenpeace last year, and still available online, retailers and canning companies were ranked in order of their tuna-fishing policies. The bycatch which is going on is criminal," he said yesterday. From now on, his company is insisting only on pole and line-caught skipjack. The first canned tuna came out in California canner Albert P. Halfhil, previously a sardine man, was the one who realized that when tuna is steamed it turns an appealing white color and has a pleasantly mild flavor.
Sardines were first packed at Nantes, France, in , and by a fairly good market had been created for French sardines in this country. In , shortly before the industry began to consolidate, the number of canneries peaked at With proper storage methods, your canned tuna will most likely stay good on the shelf for anywhere from years, which is an incredible length of time.
Canned tuna typically has an expiration date. This eliminated the need for solder and provided for cost reduction and improved manufacturing speed. In , machinery was developed to crimp the can ends to the sides with a double seam sealed with a rubber compound. This new method used rollers to shape the can, allowing manufacturers to begin producing can bodies via sheets of coated tin plate.
Rectangles were cut and curled around a die and then welded together to create the cylinder with a side seam. The top and bottom of the can were flared to create a quarter flange around the edge. Ends were die-cut, shaped, and pressed to fit snuggly on the top and bottom of the can. The body and the bottom end were brought together through a final seam by the can maker and the top end applied by the filler.
In , the double seam cans were in full production and dominated the market by In , aluminum was introduced as a more durable and recyclable solution for metal can making.
It was officially introduced to the market in by beer-makers Adolf Coors Company. From coated and lined tin-free cans, the production of aluminum cans were created in two different ways: three-piece and two-piece. Figure 1.
Three-piece can side seams a soldered; b cemented; c welded. Courtesy of Proceedings, 3rd International Tinplate Conference , Available from Researchgate. In , more than years after a steamboat named the Bertrand sank in the Missouri River, canned food was retrieved from the shipwreck and tested to determine if it was still safe to eat.
There was no trace of microbial growth found. The smell and appearance had suffered, but even after years, it was perfectly safe. As the decades went by, automation, monitoring control systems, and improved processes have led to more efficient can making world-wide. Statistical tracking of production flow, downtime, spoilage, and scrap has become key in remaining competitive and keeping up with the ebb and flow of demand.
Freshness, convenience, and efficiency remain front of mind for industry engineers, as they continue to work on advancements in protective linings, bonding materials, printing, and ease-of-use features. With less guesswork, can makers are growing their businesses and fueling decisions with accurate real-time data. Large can makers are turning to enterprise-wide Production Information Systems for insight into their high-volume operations, as well as, overall productivity and efficiency.
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