Антарктика крилі: балық аулау, өңдеу және қолданылуы

The krill fishery is the commercial fishery of krill, small shrimp like marine animals that live in the oceans world wide. The present estimate for the biomass of Antarctic krill (Euphausia superba) is 379 million tonnes. The total global harvest of krill from all fisheries amounts to 150–200,000 tonnes annually, mainly Antarctic krill and North Pacific krill (E. pacifica). Krill are rich in protein (40% or more of dry weight) and lipids (about 20% in E. superba). Their exoskeleton amounts to some 2% of dry weight of chitin. They also contain traces of a wide array of hydrolytic enzymes such as proteases, carbohydrases, nucleases and phospholipases, which are concentrated in the digestive gland in the cephalothorax of the krill. Most krill is used as aquaculture feed and fish bait; other uses include livestock or pet foods. Only a small percentage is prepared for human consumption. Their enzymes are interesting for medical applications, an expanding sector since the early 1990s.

Krill are small animals, considered a type of zooplankton, and hence need to be fished with fine meshed plankton nets. Such nets pose several problems: they tend to clog fast, and they have high drag, producing a bow wave that deflects the krill to the sides. Trawling must hence be done at low speeds. Additionally, fine nets are delicate, and the first krill nets designed exploded while fishing through the krill schools. Furthermore, fine nets increase unwanted bycatch, such as fish fingerlings, which might have unforeseen side effects on the ecosystem, even though large krill aggregations tend to be monospecific. Another problem is bringing the krill catch on board. When the full net is hauled out of the water, the organisms compress each other, resulting in great loss of the krill's liquids. Experiments have been carried out to pump Antarctic krill, while still in water, from the cod end of the net through a large tube on board. This method had already been used by the small fishing boats in Japanese waters; it increases the capture capacity and the processing rate of krill. One of the first Antarctic krill trawlers to use this technique was the FV Atlantic Navigator, registered in Vanuatu and owned by the Norwegian based company Aker ASA, which used this technique in the 2003/04 and 2004/05 fishing seasons. In these seasons, this ship alone caught 25% and 38% of the whole krill catch in CCAMLR regions. The successor ship of the Atlantic Navigator, the FV Saga Sea, can fish up to about 120,000 tonnes of krill annually, and Aker announced plans to build more such ships Antarctic Endurance launching early 2019. Krill must be processed within one to three hours after capture due to the rapid enzymatic breakdown and the tainting of the meat by the intestines. They must be peeled because their exoskeleton contains fluorides, which are toxic in high concentrations.

Most krill is processed to produce fish food for use in aquariums and aquacultures. The krill is sold freeze dried, either whole or pulverized. Krill as a food source is known to have positive effects on some fish, such as stimulating appetite or resulting in an increased disease resistance. Furthermore, krill contains carotenoids and is thus used sometimes as a pigmentizing agent to color the skin and meat of some fish. About 34% of the Japanese catch of E. superba and 50% of E. pacifica are used for fish food; the Canadian catch is used almost exclusively for this purpose. One quarter of the Japanese catch of E. superba is used in the form of fresh frozen krill as fish bait and half the E. pacifica catch is used as chum for sport fishing. The Japanese industry produces boiled, frozen krill and peeled tail meat. Other uses include krill pastes or processed krill as food additives, e. g. in the form of krill oil gel capsules. Only a small amount of E. superba is processed for human consumption. Medical applications of krill enzymes include products for treating necrotic tissue and as chemonucleolytic agents. Of the 376 krill related patents that had been registered world wide until 2002, 17% related to medical uses. Most of these medical patents had been registered after 1988.

The krill fishery in Japanese waters primarily targets the North Pacific krill (Euphausia pacifica), which reaches a size of about The annual catch is of the order of 60–70,000 tonnes. Minor fisheries for Euphausia nana (a few thousand tonnes) and Thysannoessa inermis (a few hundred tonnes annually) also exist. The fishing ground are all above the continental shelf close to the coast and at most deep. E. nana reaches only 1.2 cm, and T. inermis can grow to
E. pacifica was fished as early as the 19th century. Fishing is done with small boats. The traditional technique uses bow mounted trawls, augmented by fish pumps since the 1980s. A bow mounted trawl can exploit only surface swarms of krill up to a depth of about eight metres. In the 1970s, the krill fishery expanded drastically and began to use also one or two boat seines, which can catch swarms as deep as A peak in the krill production was reached in 1992 with over 100,000 tonnes. The following year, catch regulations were enforced, and since then the annual catch has been reduced by about 30%.

Small scale fisheries for krill also exist in other areas. In Canada, fishing for E. pacifica takes place in the Strait of Georgia off British Columbia; there is a government imposed catch limit of 500 tonnes per year. Fisheries targeting the Northern krill (Meganyctiphanes norvegica), a medium sized krill reaching body lengths of more than , as well as Tysanoessa raschii (2 cm) and T. inermis in the Gulf of St. Lawrence and on the Scotian Shelf have been proposed, but didn't get beyond early experimental stages. They are limited to harvesting a few hundred tonnes of krill per year, and Nicol & Foster consider it unlikely that any new large scale harvesting operations in these areas will be started due to the opposition from local fishing industries and conservation groups.