Sockeye Salmon (Oncorhynchus nerka)
Pragya Tripathi
National Geographic Website http://animals.nationalgeographic.com/animals/fish/sockeye-salmon/
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“Salmon, shad, and alewives were formerly abundant here, and taken in weirs by the Indians ... until the dam and afterward the canal at Billerica, and the factories at Lowell, put an end to their migrations hitherward; though it is thought that a few more enterprising shad may still occasionally be seen in this part of the river.... Perchance, after a few thousands of years, if the fishes will be patient, and pass their summers elsewhere meanwhile, nature will have leveled the Billerica dam, and the Lowell factories, and the Grass-ground River run clear again, to be explored by new migratory shoals.” - Henry David Thoreau (Dictionary.com) |
Taxonomy
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Salmoniformes Family: Salmonidae Genus: Oncorhynchus Species: nerka [2] |
Among the seven salmon species found in the Pacific ocean, sockeyes are the smallest. [1] However, their succulent, bright-orange meat is prized above all others. Sockeye salmon meat gets its color from the orange krill they eat while in the ocean. [4] The name sockeye comes from a poor attempt to translate the word suk-kegh which means red fish in British Columbia's native Coast Salish language. [1] The average sized sockeye salmon are up to 33 inches (84 cm) and the weight is 5 to 15 lbs (2.3 to 7 kg). [4] They are anadromous by nature; they live in the ocean but enter fresh water to spawn. They cannot be harvested in an aquaculture environment because of their unique diet habits and lifecycle.
Sockeyes are caught by the fisheries using gillnets, vertical panels of netting attached to a small boat. They are usually caught in the ocean on their way back to freshwater to spawn. According to the data from International Union for Conservation of Nature (IUCN), out of 98 subpopulations in the Alaskan coastline and lakes, only five are extinct. Therefore, they are quite abundant in number. However, there has been a decline in the runs Sockeye makes back to the spawning areas. The future numbers of the population is in the decline.
Sockeyes are caught by the fisheries using gillnets, vertical panels of netting attached to a small boat. They are usually caught in the ocean on their way back to freshwater to spawn. According to the data from International Union for Conservation of Nature (IUCN), out of 98 subpopulations in the Alaskan coastline and lakes, only five are extinct. Therefore, they are quite abundant in number. However, there has been a decline in the runs Sockeye makes back to the spawning areas. The future numbers of the population is in the decline.
Like all species of Pacific salmon, sockeye salmon are anadromous, living in the ocean but entering fresh water to spawn. [3] While in the ocean, the sockeye salmon are greenish-blue with fine black speckles on back. [17] Thus, sockeye salmon are sometimes called blueback salmons. [4] Spawning males have pale green heads, dark jaws, pale undersides and bright red bodies. Spawning females look generally the same; except, they have more subdued coloration. While spawning, they turn bright red with a green head right after they enter fresh water. The size of an adult returning to spawn may measure up to 2.8 feet (32 in) in length and weigh an average of 8 pounds (3.6 kg). [2]
Maturing sockeye salmon are filter feeders, feeding on a variety of planktons. [18] At their larval stage, they feed on zooplankton, which they continue to feed on till their adult stage. An adult Sockeye salmon also feeds on insects, small crustaceans, and occasionally squid and small fish. [2] Sockeye flesh gains its brilliant orange-red color from an antioxidant called astaxanthin. [18] Astaxanthin is a naturally-occurring pigment found in the zooplankton that salmon eat.
Sockeye’s anadromous life cycle starts when an adult female Sockeye salmon deposits her eggs in gravel beds in freshwater streams and rivers. [1] Once the eggs have been fertilized by the male Sockeye salmon, the embryos will incubate over the winter months and then hatch into alevins in late winter. [1] In the alevins phase, they take on a strange appearance of large eyes and a ballooning orange sack and pencil like body. [1] Approximately 4 months after becoming an alevin, the young salmon changes into a fry. [1] A Sockeye salmon fry averages 1 inch in length, has an elongated body and swims freely. [4]
Juvenile sockeyes stay in their natal habitat for up to three years, more than any other salmon. [1] In systems with lakes, sockeye salmon usually spend one to three years in fresh water, before migrating to the ocean. [3] However, in systems without lakes, they migrate to the ocean soon after emerging from the gravel. [3] A fry, then, changes into a smolt when it is ready to head to the ocean were it will stay until it matures into an adult Sockeye salmon. They continue to grow until they reach maturity at four to five years of age. The mature female Sockeye salmon will begin its journey back to its place of origin were it will deposit its bounty of eggs in order to continue the salmon life cycle. As they return upriver to their spawning grounds, sockeyes eventually die after spawning. [4]
Sockeye salmon, which is the third most abundant salmon species, is a culturally and economically important resource to commercial fishermen throughout Alaska, British Columbia, Washington and Oregon. Sockeye salmon rank second in commercial landings to the pink salmon. However, their meat is given more value due to their bright-orange color. They are also an important sustaining food source and a valuable recreational resource. Additionally, the landlocked sockeye is a very important freshwater sport fish. [17]
Maturing sockeye salmon are filter feeders, feeding on a variety of planktons. [18] At their larval stage, they feed on zooplankton, which they continue to feed on till their adult stage. An adult Sockeye salmon also feeds on insects, small crustaceans, and occasionally squid and small fish. [2] Sockeye flesh gains its brilliant orange-red color from an antioxidant called astaxanthin. [18] Astaxanthin is a naturally-occurring pigment found in the zooplankton that salmon eat.
Sockeye’s anadromous life cycle starts when an adult female Sockeye salmon deposits her eggs in gravel beds in freshwater streams and rivers. [1] Once the eggs have been fertilized by the male Sockeye salmon, the embryos will incubate over the winter months and then hatch into alevins in late winter. [1] In the alevins phase, they take on a strange appearance of large eyes and a ballooning orange sack and pencil like body. [1] Approximately 4 months after becoming an alevin, the young salmon changes into a fry. [1] A Sockeye salmon fry averages 1 inch in length, has an elongated body and swims freely. [4]
Juvenile sockeyes stay in their natal habitat for up to three years, more than any other salmon. [1] In systems with lakes, sockeye salmon usually spend one to three years in fresh water, before migrating to the ocean. [3] However, in systems without lakes, they migrate to the ocean soon after emerging from the gravel. [3] A fry, then, changes into a smolt when it is ready to head to the ocean were it will stay until it matures into an adult Sockeye salmon. They continue to grow until they reach maturity at four to five years of age. The mature female Sockeye salmon will begin its journey back to its place of origin were it will deposit its bounty of eggs in order to continue the salmon life cycle. As they return upriver to their spawning grounds, sockeyes eventually die after spawning. [4]
Sockeye salmon, which is the third most abundant salmon species, is a culturally and economically important resource to commercial fishermen throughout Alaska, British Columbia, Washington and Oregon. Sockeye salmon rank second in commercial landings to the pink salmon. However, their meat is given more value due to their bright-orange color. They are also an important sustaining food source and a valuable recreational resource. Additionally, the landlocked sockeye is a very important freshwater sport fish. [17]
Marine Exchange of Southern California (mxsocal.org)
Sockeye salmon and other members of the same genus are said to have been evolved from a primitive trout genus Salmo. The evolution is believed to have occurred during a series of geographical isolations around the North Pacific rim as ocean elevations fell and rose during glacial changes in the early Pleistocene period [5].
Today, fresh water lakes, streams and estuaries provide important habitat for spawning and rearing sockeye salmon. On the west coast of North America, sockeye salmon range from the Klamath River in Oregon to Point Hope in northwestern Alaska. The largest sockeye salmon populations are in the Kvichak, Naknek, Ugashik, Egegik, and Nushagak Rivers that flow into Alaska’s Bristol Bay, plus the Fraser River system in Canada. In good years, these runs can number in the tens of millions of fish. [3] Alaska's 34,000-mile coastline is home to the most abundant and healthiest salmon stocks in the world. The Marine Stewardship Council (MSC) has certified Alaska's salmon as "sustainable." The Council is an international nonprofit organization that promotes sustainable fishing practices worldwide and guides consumer-buying habits through eco-labeling. [6]
Many fisheries have found out that harvesting sockeye salmon in a farm is impossible because of their anadromous nature. Attempts to farm them have not been commercially successful. Sockeye have a unique diet and lifecycle that are not easily replicated in an aquaculture environment. Thus, there are some hatcheries near dams in many river systems, which raise sockeye salmon in its early stage before they are released in freshwater. [6]
Therefore, Sockeye Salmon are harvested using method called gillnetting. Gillnets are vertical panels of netting normally set in a straight line. Fish may be caught by gill nets in 3 ways:
(1) wedged – held by the mesh around the body
(2) gilled – held by mesh slipping behind opercula, the gill plate
(3) tangled – held by teeth, spines, maxillaries, or other protrusions without the body penetrating the mesh. [8]
Most often salmon are gilled. When salmon swim into gillnets, their heads are caught just behind the gill plate. When they struggle to free themselves, the twine slips behind the gill cover and prevents escape. Gillnets are set in coastal areas across the path of returning salmon. This method of fishing is done using small one- or two-person boats that drift as they allow the net to "soak." Gillnetting can also be done from the shore. The mesh openings in the net are regulated to ensure that they catch only fish of a desired size. The nets are hauled aboard the fishing boat by a hydraulic drum, and the fish are removed from the net by hand. Gillnets are mainly used in Bristol Bay and in limited areas throughout Alaska to catch sockeye salmon and few other types of salmon. [7]
Sockeye salmon are also caught using purse seines. A purse seine is a fishing seine that is drawn into the shape of a bag to enclose the catch. A smaller boat is used to control the free end of the net until the larger vessel comes around to complete the encircling. While using gillnets and purse seines, the size of the net is controlled to catch sockeye and avoid by-catch. They rarely touch the seafloor so there is little lasting physical impact on the benthic habitats. [19]
Today, fresh water lakes, streams and estuaries provide important habitat for spawning and rearing sockeye salmon. On the west coast of North America, sockeye salmon range from the Klamath River in Oregon to Point Hope in northwestern Alaska. The largest sockeye salmon populations are in the Kvichak, Naknek, Ugashik, Egegik, and Nushagak Rivers that flow into Alaska’s Bristol Bay, plus the Fraser River system in Canada. In good years, these runs can number in the tens of millions of fish. [3] Alaska's 34,000-mile coastline is home to the most abundant and healthiest salmon stocks in the world. The Marine Stewardship Council (MSC) has certified Alaska's salmon as "sustainable." The Council is an international nonprofit organization that promotes sustainable fishing practices worldwide and guides consumer-buying habits through eco-labeling. [6]
Many fisheries have found out that harvesting sockeye salmon in a farm is impossible because of their anadromous nature. Attempts to farm them have not been commercially successful. Sockeye have a unique diet and lifecycle that are not easily replicated in an aquaculture environment. Thus, there are some hatcheries near dams in many river systems, which raise sockeye salmon in its early stage before they are released in freshwater. [6]
Therefore, Sockeye Salmon are harvested using method called gillnetting. Gillnets are vertical panels of netting normally set in a straight line. Fish may be caught by gill nets in 3 ways:
(1) wedged – held by the mesh around the body
(2) gilled – held by mesh slipping behind opercula, the gill plate
(3) tangled – held by teeth, spines, maxillaries, or other protrusions without the body penetrating the mesh. [8]
Most often salmon are gilled. When salmon swim into gillnets, their heads are caught just behind the gill plate. When they struggle to free themselves, the twine slips behind the gill cover and prevents escape. Gillnets are set in coastal areas across the path of returning salmon. This method of fishing is done using small one- or two-person boats that drift as they allow the net to "soak." Gillnetting can also be done from the shore. The mesh openings in the net are regulated to ensure that they catch only fish of a desired size. The nets are hauled aboard the fishing boat by a hydraulic drum, and the fish are removed from the net by hand. Gillnets are mainly used in Bristol Bay and in limited areas throughout Alaska to catch sockeye salmon and few other types of salmon. [7]
Sockeye salmon are also caught using purse seines. A purse seine is a fishing seine that is drawn into the shape of a bag to enclose the catch. A smaller boat is used to control the free end of the net until the larger vessel comes around to complete the encircling. While using gillnets and purse seines, the size of the net is controlled to catch sockeye and avoid by-catch. They rarely touch the seafloor so there is little lasting physical impact on the benthic habitats. [19]
International Union for Conservation of Nature (IUCN) Red List
http://jr.iucnredlist.org/documents/attach/SockeyeSalmon_SupportingDoc.pdf
http://jr.iucnredlist.org/documents/attach/SockeyeSalmon_SupportingDoc.pdf
According to the data from International Union for Conservation of Nature (IUCN), out of 98 subpopulations in the Alaskan coastline and lakes, only five are extinct. However, since past decade, there has been a decline in the number of Sockeye Salmons making their run back to their spawning freshwater areas from ocean. In 2009, scientists recorded the lowest number of sockeye salmon in 50 years in the massive Fraser River system in British Columbia. A various number of reasons can be associated with it.
1. Human obstruction of Sockeye’s path to freshwater spawning areas
Dam construction has seemed to affect a lot of fisheries species due to the obstruction they create. Indeed, a lot of sockeye salmon have been obstructed by dams from making their journey. Some dams have fish ladders to help the fishes and other water organisms pass through. Statistics show that even the construction of fish ladder has not helped at all. Since Bonneville Dam outside Portland was built in 1938, there have been times when there weren't 38,000 sockeye salmon swimming over the fish ladders in a whole year. [14]
2. Fish farms of other species near Sockeye’s habitat
One might think that the farms of other fisheries should not affect the sockeye population, which is not reared in farms. However, the truth is - fish farms near the Sockeye salmon’s spawning areas release a lot of waste and have been the primary source of sea lice in the freshwater river systems. Sea lice are small marine parasites that occur naturally on many different species of wild fish including wild adult salmon. Sea lice are planktonic and are transported on the tide. When they encounter marine fish they attach themselves, usually on the skin, fins and/or gills and feed off the mucous or skin. [10] Sea lice from salmon farms are one of the most significant threats facing wild salmon in British Columbia, Canada. The year round fish farms with hundreds of thousands of fish in small areas (net-cages) are ideal and unnatural breeding grounds for lice. Infestations on farms significantly increase the number of lice in surrounding waters, far beyond what would occur naturally. In the spring, when fish eggs hatch and juvenile Sockeye salmon emerge from the rivers and make their way to the ocean many are exposed to sea lice during their journey because fish farms are typically located in sheltered waters along wild salmon migration routes.
3. Sea Temperature
Although Sockeye Salmon’s behavior is difficult to track when they are in the ocean, some scientists attribute their decline to the decrease in temperature of sea around Alaska.
Since Sockeye Salmon is a 10 million dollar industry, biologists and conservationists are trying to conserve Sockeye Salmon population. In Bristol Bay near Alaska and Canada, the fisheries are being managed biologically to ensure healthy, sustainable returns of Sockeye population. The teams of biologists monitor the salmon’s return, gauging escapement levels and comparing data with projected returns and preseason escapement goals. Fishermen are allowed to catch salmon only when the biologists are confident that in doing so, the resource does not suffer. By basing management decisions on biology, and not economics, the State of Alaska hopes to safeguard, the sustainability of Sockeye Salmon. Due to the conservation efforts, a record number of Sockeye Salmon- 400,000 of the Columbia Basin's farthest-swimming salmon are expected to return this year, almost all of them wild fish bred in rivers. [10]
1. Human obstruction of Sockeye’s path to freshwater spawning areas
Dam construction has seemed to affect a lot of fisheries species due to the obstruction they create. Indeed, a lot of sockeye salmon have been obstructed by dams from making their journey. Some dams have fish ladders to help the fishes and other water organisms pass through. Statistics show that even the construction of fish ladder has not helped at all. Since Bonneville Dam outside Portland was built in 1938, there have been times when there weren't 38,000 sockeye salmon swimming over the fish ladders in a whole year. [14]
2. Fish farms of other species near Sockeye’s habitat
One might think that the farms of other fisheries should not affect the sockeye population, which is not reared in farms. However, the truth is - fish farms near the Sockeye salmon’s spawning areas release a lot of waste and have been the primary source of sea lice in the freshwater river systems. Sea lice are small marine parasites that occur naturally on many different species of wild fish including wild adult salmon. Sea lice are planktonic and are transported on the tide. When they encounter marine fish they attach themselves, usually on the skin, fins and/or gills and feed off the mucous or skin. [10] Sea lice from salmon farms are one of the most significant threats facing wild salmon in British Columbia, Canada. The year round fish farms with hundreds of thousands of fish in small areas (net-cages) are ideal and unnatural breeding grounds for lice. Infestations on farms significantly increase the number of lice in surrounding waters, far beyond what would occur naturally. In the spring, when fish eggs hatch and juvenile Sockeye salmon emerge from the rivers and make their way to the ocean many are exposed to sea lice during their journey because fish farms are typically located in sheltered waters along wild salmon migration routes.
3. Sea Temperature
Although Sockeye Salmon’s behavior is difficult to track when they are in the ocean, some scientists attribute their decline to the decrease in temperature of sea around Alaska.
Since Sockeye Salmon is a 10 million dollar industry, biologists and conservationists are trying to conserve Sockeye Salmon population. In Bristol Bay near Alaska and Canada, the fisheries are being managed biologically to ensure healthy, sustainable returns of Sockeye population. The teams of biologists monitor the salmon’s return, gauging escapement levels and comparing data with projected returns and preseason escapement goals. Fishermen are allowed to catch salmon only when the biologists are confident that in doing so, the resource does not suffer. By basing management decisions on biology, and not economics, the State of Alaska hopes to safeguard, the sustainability of Sockeye Salmon. Due to the conservation efforts, a record number of Sockeye Salmon- 400,000 of the Columbia Basin's farthest-swimming salmon are expected to return this year, almost all of them wild fish bred in rivers. [10]
Global Assessment of Extinction Risk to Populations of Sockeye Salmon; plosone.org
The table above shows the decline of Sockeye population over last 3 generations from the IUCN Red List. The Red List directs the use of A2 for species such as the sockeye salmon, where population reduction or its causes may not have ceased or may not be fully understood or may not be reversible. According to the table, the sub-populations of Sockeye who were in the Critically Endangered criteria have declined by 80%, the Endangered species by 20% and the Vulnerable species by 30%. [15] From this data, one can conclude that while Sockeye salmon are still in abundance, they are slowly declining.
Due to the difficulty in forecasting, the forecasts for Sockeye Salmon is mostly found for individual river systems. Looking at the data from the largest salmon spawning area - Bristol Bay, the decline of Sockeye population seems inevitable. A total of 26.03 million sockeye salmon are expected to return to Bristol Bay in 2013. This prediction is 33% lower than the previous 10-year mean of total runs (39.06 million; range of 24.1 million to 46.60 million), and 20% lower than the long-term mean of 32.38 million. The forecast range is from 17.30 million to 34.76 million. [16] The forecast for the sockeye salmon run to Bristol Bay in 2013 is the sum of individual predictions for nine river systems (Kvichak, Alagnak, Naknek, Egegik, Ugashik, Wood, Igushik, Nushagak-Mulchatna, and Togiak rivers) and four age classes (ages 1.2, 1.3, 2.2, and 2.3, plus ages 0.3 and 1.4 for Nushagak River). Adult escapement and return data from brood years 1972–2009 were used in the analyses. Historically, total runs of sockeye salmon to Bristol Bay have been highly variable. In seven consecutive years from 2004–2010, the total run was close to or exceeded 40 million sockeye salmon. In 2011, total run dropped to 31.91 million sockeye salmon. Thus, the 2013 run is expected to be less than the total run in 2012. [16]
Although salmon fisheries are carefully managed in some parts of Pacific to ensure sustainability of the stocks, the sockeye salmon do not have a bright future. The sockeye population is not at risk at the species-level; however, about one-third of the sub-populations are at risk or already extinct. The prediction of the future of sockeye salmon is still difficult because they travel to ocean where it’s quite difficult to keep their track. Since there has been a decline in Sockeye population coming back to spawning areas, we can surmise that the future population of salmon is in decline due to low spawning rates.
Due to the difficulty in forecasting, the forecasts for Sockeye Salmon is mostly found for individual river systems. Looking at the data from the largest salmon spawning area - Bristol Bay, the decline of Sockeye population seems inevitable. A total of 26.03 million sockeye salmon are expected to return to Bristol Bay in 2013. This prediction is 33% lower than the previous 10-year mean of total runs (39.06 million; range of 24.1 million to 46.60 million), and 20% lower than the long-term mean of 32.38 million. The forecast range is from 17.30 million to 34.76 million. [16] The forecast for the sockeye salmon run to Bristol Bay in 2013 is the sum of individual predictions for nine river systems (Kvichak, Alagnak, Naknek, Egegik, Ugashik, Wood, Igushik, Nushagak-Mulchatna, and Togiak rivers) and four age classes (ages 1.2, 1.3, 2.2, and 2.3, plus ages 0.3 and 1.4 for Nushagak River). Adult escapement and return data from brood years 1972–2009 were used in the analyses. Historically, total runs of sockeye salmon to Bristol Bay have been highly variable. In seven consecutive years from 2004–2010, the total run was close to or exceeded 40 million sockeye salmon. In 2011, total run dropped to 31.91 million sockeye salmon. Thus, the 2013 run is expected to be less than the total run in 2012. [16]
Although salmon fisheries are carefully managed in some parts of Pacific to ensure sustainability of the stocks, the sockeye salmon do not have a bright future. The sockeye population is not at risk at the species-level; however, about one-third of the sub-populations are at risk or already extinct. The prediction of the future of sockeye salmon is still difficult because they travel to ocean where it’s quite difficult to keep their track. Since there has been a decline in Sockeye population coming back to spawning areas, we can surmise that the future population of salmon is in decline due to low spawning rates.
1. National Geographic
http://animals.nationalgeographic.com/animals/fish/sockeye-salmon/
2. NOAA Fisheries
http://www.nmfs.noaa.gov/pr/species/fish/sockeyesalmon.htm
3. Alaska Government
http://www.adfg.alaska.gov/index.cfm?adfg=sockeyesalmon.main
4. Wild Pacific Salmon
http://www.wildpacificsalmon.com/site/680079/PAGE/505912
5. Burgner, Robert L. "Life History of Sockeye Salmon". Pacific Salmon Life Histories. Vancouver, 1991.UBC press. page 3.
6. Smoky Bay Fisheries
http://smokybayfish.com/html/aboutfish.html
7. http://northpacificseafoods.com/content/view/97/362/
8. Murphy, B. and Willis, D. (1996) "Fisheries Techniques: Second edition." Bethesda, MD: American Fisheries Society.
9. http://www.globaltvbc.com/report+into+decline+of+bcs+sockeye+fishery+critical+of+salmon+farming...
10. http://www.farmedanddangerous.org/salmon-farming-problems/
11. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0016851
12. http://www.nature.com/news/government-confusion-is-harming-sockeye-salmon-1.11727
13. http://www.globaltvbc.com/report+into+decline+of+bcs+sockeye+fishery+critical+of+salmon+farming...
14. http://www.nbcnews.com/id/47991126/ns/us_news-environment/#.UUCxXdaG1js
15. Rand PS, Goslin M, Gross MR, Irvine JR, Augerot X, et al. (2012) Global Assessment of Extinction Risk to Populations
of Sockeye Salmon Oncorhynchus nerka. PLoS ONE 7(4): e34065. doi:10.1371/journal.pone.0034065
16. 2013 Bristol Bay Sockeye Salmon Forecast
http://www.adfg.alaska.gov/static/home/news/pdfs/newsreleases/cf/238496858.pdf
17. http://www.psmfc.org/habitat/edu_sockeye_facts.html
18. http://www.redsalmon.com/fish_2.html
19. http://www.fishchoice.com/For-BUYERS/Seafood-Market-Summaries/Sockeye-Salmon/tabid...
http://animals.nationalgeographic.com/animals/fish/sockeye-salmon/
2. NOAA Fisheries
http://www.nmfs.noaa.gov/pr/species/fish/sockeyesalmon.htm
3. Alaska Government
http://www.adfg.alaska.gov/index.cfm?adfg=sockeyesalmon.main
4. Wild Pacific Salmon
http://www.wildpacificsalmon.com/site/680079/PAGE/505912
5. Burgner, Robert L. "Life History of Sockeye Salmon". Pacific Salmon Life Histories. Vancouver, 1991.UBC press. page 3.
6. Smoky Bay Fisheries
http://smokybayfish.com/html/aboutfish.html
7. http://northpacificseafoods.com/content/view/97/362/
8. Murphy, B. and Willis, D. (1996) "Fisheries Techniques: Second edition." Bethesda, MD: American Fisheries Society.
9. http://www.globaltvbc.com/report+into+decline+of+bcs+sockeye+fishery+critical+of+salmon+farming...
10. http://www.farmedanddangerous.org/salmon-farming-problems/
11. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0016851
12. http://www.nature.com/news/government-confusion-is-harming-sockeye-salmon-1.11727
13. http://www.globaltvbc.com/report+into+decline+of+bcs+sockeye+fishery+critical+of+salmon+farming...
14. http://www.nbcnews.com/id/47991126/ns/us_news-environment/#.UUCxXdaG1js
15. Rand PS, Goslin M, Gross MR, Irvine JR, Augerot X, et al. (2012) Global Assessment of Extinction Risk to Populations
of Sockeye Salmon Oncorhynchus nerka. PLoS ONE 7(4): e34065. doi:10.1371/journal.pone.0034065
16. 2013 Bristol Bay Sockeye Salmon Forecast
http://www.adfg.alaska.gov/static/home/news/pdfs/newsreleases/cf/238496858.pdf
17. http://www.psmfc.org/habitat/edu_sockeye_facts.html
18. http://www.redsalmon.com/fish_2.html
19. http://www.fishchoice.com/For-BUYERS/Seafood-Market-Summaries/Sockeye-Salmon/tabid...