Utilization of by-products in the fish industry

Abstract

The global annual harvesting of fish from the wild in oceans and lakes was 90.2 and 93 million tons in 2002 and 2003, respectively, and has been around 90 million tons in the last decade (STATICE, 2005). The Pacific Ocean has been the main harvesting ground with about 50 million tons followed by the Atlantic Ocean at around 20 million tons (Figure 12.1). The number one species has been Peruvian anchovy, ranging from 6.2 to 11.3 million tons in the past few years, but the El Nino storm has caused some major fluctuations in the stock and harvesting. Alaskan Pollock has been in second place at around 3 million tons, with Atlantic herring and Skipjack tuna following at about 2 million tons each 1, about 1 million tons of Capelin, which is a small pelagic schooling fish like the anchovy. Around 1 million tons of Atlantic cod have been harvested in recent years (Figure 12.1). The leading fishing nation in the world has been China with more than 16 million tons, followed by Peru at 6 and the United States at 5 million tons. Russia has ranked number 8 with between 3 and 4 million and Norway and Iceland have been the leading European fishing nations ranking as number 11-15 worldwide with 2.5 and 2 million tons but at the top of the list for the North Atlantic. Wild fish stocks are a limited resource and overfishing has been a problem in many fishing grounds, although the severity has varied greatly between fish species and regions. Modernization and increased capacity of fishing vessels has increased opportunities and ability to find and harvest fish in the ocean; now we are at a stage where most fish species are being harvested to their limit. Sustainability of the stock and increased or total utilization of the harvested fish therefore is very important from an environmental point of view. The particular species of fish being harvested and utilized is also important with respect to environmental sustainability. All life in the oceans is based on phytoplankton like seaweed, but phytoplankton production is gigantic; with respect to organic material it has been estimated to be ∼10,000 times the world production of wheat and rice. There are not many fish species in the ocean feeding directly on plankton, like livestock on land feeds on grass; only some sardines, menhaden, and anchovies. The plankton feeders belonging to the second production step according to the "production pyramid" put forth by Georg Borgstrom some 50 years ago (Figure 12.2). His pyramid is still valid and it would be beneficiary if we could utilize more of the species in the lower production steps for human consumption.