.. (and) globally, 52% of the stocks are at a healthy level of abundance, 39% are over-shed and 9% are at an intermediate level" (3). The International Union for Conservation of Nature (IUCN) Red List of Threatened Species has found that because "this species has been intensively fished since the early 1950s "estimated (that) spawning stock biomass has declined approximately 85% over the past 36 years (1973 -- 2009) and there is no sign that the spawning stock is rebuilding" (1). Today, the majority of canned tuna purchased by consumers is sourced from commercial "fish farms" and industrial fisheries that maintain enormous populations of captive tuna born and bred as a food source. 4.) by what methods are these products processed? Describe the methods. This description should include the conditions for holding of fresh foods, "minimally processed" methods, as well as more extensive methods of preservation, e.g. caning, freezing, drying, fermentation, concentration etc.

5.) for these foods what are the problems encountered during the processing of these foods and how are these products overcome? (e.g. milk when dried may be hard to rehydrate)

The method of processing used to bring tuna from capture to kitchen is entirely dependent on the intended use. For traditional canned tuna, processing typically involves an assembly line utilizing either human or machine labor to gut the fish, with a precooking...

Canned tuna is most often soaked in water, oil, or brine for the sake of preservation, with the can being sealed by a heat-based pressurization process. In the case of tuna destined for the sushiman's slab, however, the largest and most desirable fish stock are frozen immediately after capture and auctioned to the highest bidder nearly immediately after. Sushi-grade tuna like maguro and toro requires little to no processing in the traditional sense, with sushi chefs purchasing their fish at auction, transporting them to the restaurant, and preparing the fish according to cultural standards.
Works Cited

Fonteneau, Alain. "Species composition of tuna catches taken by purse seiners." Western and Central Pacific Fisheries Division. 22 Aug 2008: Web. 5 Apr. 2013. .

Greenberg, Paul. "A Tale of Two Cans: Why Canned Salmon Is Better Than Tuna." The Atlantic. 12 Aug 2011: Web. 4 Apr. 2013 .

Sepulveda, C.A.; Dickson, K.A.; Bernal, D.; Graham, J.B. (2008). "Elevated red myotomal muscle temperatures in the most basal tuna species, Allothunnus fallai." Journal of Fish Biology 73(1): 241 -- 249. Web. 4 Apr. 2013. .

United States Department of Agriculture. The USDA National Nutrient Database for Standard Reference. Washington, DC: Government Printing Office, 2011. Web. .