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change title

farmed vs. wild??

North America vs. rest of world is egotistical... add other specific countries? rename?

Add more to climate change section with my Project 2 work?? or create into subsections....

Environmental issues with salmon ----> Environmental impacts on salmon  ???

Gillnets are designed to harvest a specific sized fish. For example, Washington Department of Fish and Wildlife's 2010 Commercial Regulations had a 7-inch (180 mm) minimum mesh size restriction for Chinook, and a 5-inch (130 mm) minimum – 5.5-inch (140 mm) maximum for sockeye.[4] Possible problems arising from this selective harvest are smaller reproducing adult fish, as well as the unexpected mortality of the fish which sustain injuries from the gillnet but are not retained in the fishery. Most salmon populations include several age classes, allowing for fish of different ages, and sizes, to reproduce with each other. A recent 2009 study looked at 59 years of catch and escapement data of Bristol Bay sockeye to determine age and size at maturity trends attributable to the selectivity of commercial gillnet harvests. The study found that the larger females (>550 mm) of all age classes were most susceptible to harvest.^[3] The study suggests that smaller, younger fish were more likely to successfully traverse the gillnet fishery and reproduce than the larger fish. The study also found that the average length of sockeye harvested from 1946–2005 was 8 mm larger than the sockeye who escaped the gillnet fishery to spawn, reducing the fecundity of the average female by 5%, or 104 eggs.^[3]

If a salmon enters a gillnet, but manages to escape, it often sustains injuries. These injuries can lead to a lower degree of reproductive success. A study aimed at quantifying mortality of Bristol Bay sockeye salmon due to gillnet-related injuries found that 11 – 29% of sockeye sustained fishery-related injuries attributable to gillnets, 51% of those fish were expected to not reproduce.^[5]

Competition at sea

Competition between juvenile salmon entering the ocean, other wild salmon, and hatchery-released salmon in the ocean is a major factor that determines survival rates.^[6] Hatchery production has increased since 1970, and there is high spatial and trophic, dietary overlap between wild and hatchery sockeye, pink and chum salmon in the North Pacific.^[7] With more competition for prey and space in the ocean, the period of maturation in saltwater before salmon reach sexual spawning age grows. Longer times spent in the ocean causes a decline in salmon survival and abundance. Also, as the human population grows, the demand for seafood increases. With more commercial fisheries, it is difficult to maintain sustainable fishing levels.

Freshwater variables

Warming temperatures

An increase in fresh water temperature can delay spawning and accelerate the transition to smolting. Warmer temperatures of streams during spawning and incubation have negative effects on salmon productivity due to pre-spawn mortality, reduced egg survival, and temporal changes during salmon embryo development^[8]. However, the effects of higher stream temperatures during juvenile rearing vary across populations and habitats. For some watersheds as temperatures increase, an increase in turbidity and reduction in invertebrate food availability is found to cause a reduction in growth rates of juvenile salmon. For other watersheds, productivity increases with more nutrients and food availability for juvenile salmon. The salmon growth rate and maturation rate increase causing an age at maturation increase. Salmon are then able to migrate to the ocean earlier^[7].

Ulcerative dermal necrosis

(UDN) infections of the 1970s and 1980s severely affected adult salmon in freshwater rivers.

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Habitat

The loss of suitable freshwater habitat, especially degradation of stream pools and reduction of suitable material for the excavation of redds, has caused a reduction in spawning. Historically, stream pools were largely created by beavers . With their extirpation, the nurturing function of these ponds was lost. Reduced retention of the nutrients brought by the returning adult salmon in stream pools has lowered population numbers. Without stream pools, dead adult salmon tend to be washed straight back down the streams and rivers, so the nutrients are not available for the hatchlings.

The construction of dams, weirs, barriers and other "food prevention" measures bring severe adverse impacts to river habitat and on the accessibility of those habitats to salmon, particularly in the Pacific Northwest, where large numbers of dams have been built in many river systems, including over 400 in the Columbia River Basin.^[9] Other environmental factors, such as light intensity, water flow, or change in temperature, dramatically affects salmon during their migration season.^[10] Modern farming methods and various sources of pollution have resulted in loss of invertebrate diversity and population density in rivers, thus reducing food availability. Reduction in freshwater base flow in rivers and disruption of seasonal flows, because of diversions and extractions, hydroelectric power generation, irrigation schemes, barge transportation, and slackwater reservoirs, inhibit normal migratory processes and increase predation for salmon.^[11] Agricultural practices, such as the removal of riparian plants, destabilization of stream banks by livestock and irrigation processes, result in a loss of suitable low-gradient stream habitats.^[12][13]

Climate Change Impact

Climate change is affecting different types of salmon in ways from short term affects such as a decrease in population to long term affects such as evolution change. The change in temperature has left salmon most vulnerable during their egg stage, and the becoming adult stage of its life cycle (9) Climate change has caused salmon to spend less time in their natural freshwater habitat (10) (1). This type of stressor can affect the age class of salmon because it causes them to migrate at an early stage, which would cause them to delay maturation making them spend an additional year feeding in the ocean. Also, it can affect the availability for food which creates a chain reaction to their freshwater growth (1)(8).

The immediate affects consist of thermal requirements which is the critical thermal maximum for survival, and population crashes. When the water temperature increases the thermal requirements for the three species (Atlantic Salmon, Brown Trout, and Arctic Charr) are a necessity because if any other problems occur it can be predicted/anticipated by those of the biodiversity in the freshwater ecosystems (2). This can cause a population crash since the increased temperature will affect the eggs and may also bring in more diseases and illnesses towards the species (6). Although, the species may be able to adapt to the rising temperatures (7). These species of fish help support and provide for important fisheries in Western Europe, so, according to a scholarly journal their research finding say that salmon populations changes from environmental issues has a massive affect many other populations in distant habitats (2)(3). The long term affects from climate change produce more selection pressures in different parts of salmon’s life such as Juvenile growth, development rates, thermal tolerance, and disease resistance. Which shows that because of increased anthropogenic activity, or human-caused, formed these additional stressors on Salmons stages of life (4)(5).

North America

Pacific salmon populations now exist in all the Great Lakes. Coho stocks were planted in the late 1960s in response to the growing population of non-native alewife by the state of Michigan. Now Chinook (King), Atlantic, and Coho (silver) salmon are annually stocked in all Great Lakes by most bordering states and provinces. These populations are not self-sustaining and do not provide much in the way of a commercial fishery, but have led to the development of a thriving sportfishery.

Outside of North America

Native Pacific salmon populations exist in China, Taiwan, Korea, Japan, and Russia. Introduced and sustaining populations of Pacific salmon are found in New Zealand, Chile, Argentina, and the Falkland Islands.

Native Atlantic salmon populations outside of North America are found in much of coastal Europe, as well as Greenland, Iceland, the Faroe Islands, and the northwestern part of Russia.^[23] Introduced populations of Atlantic salmon, both the common anadromous life cycle and the less common land-locked life cycle, are found in many locations outside of the native range.

Relief efforts

Several governments and nongovernmental organizations (

• In the western Atlantic, the Atlantic Salmon Federation has developed a major sonic tracking technology program to understand the high at-sea mortality since the early 1990s. Ocean arrays are deployed across the
  Baie des Chaleurs and between Newfoundland and Labrador at the Strait of Belle Isle
  . Salmon have now been tracked halfway from rivers, such as the Restigouche, to Greenland feeding grounds. Now, the first line of the Ocean Tracking Network initiative is installed by DFO and Dalhousie University of Halifax, from Halifax to the edge of the continental shelf. First results include Atlantic salmon travelling from the Penobscot River in Maine, the "anchor river" for US Atlantic salmon populations.
• In the northern Atlantic, the North Atlantic Salmon Fund, led by Icelandic entrepreneur Orri Vigfússon, has worked closely since 1989 with governments and fishermen for conservation. The conservation efforts are not limited to oceans, and a sustainable angling scheme has been developed in rivers, notably in Vopnafjörður, Iceland.
• Throughout the Pacific Rim, the Wild Salmon Center partners with communities, businesses, governments, and other non-profits to protect and preserve healthy salmon ecosystems and the biodiversity on which these ecosystems depend.

Results overall show estuary problems exist for some rivers, but issues involving feeding grounds at sea are impacting populations as well. In 2008, returns were markedly improved for Atlantic salmon on both sides of the Atlantic Ocean, but no one knows if this is a temporary improvement or sign of a trend.

• Endangered Species Act
  .
• Sweden has generated a protection program as part of its
  Biodiversity Action Plan
  .
• State of Salmon maintains an
  IUCN red list of endangered salmon
  .
• The Kamchatka Peninsula, in the Russian Far East, contains the world's greatest salmon sanctuary.
• Bear Lake, Alaska, has been the site of salmon enhancement activities since 1962.^[24]

In the Pacific Northwest, one of the most notable relief efforts is the

Another notable local relief effort is the People for Puget Sound. People for Puget Sound is a citizen group founded by Kathy Fletcher in 1991 working to restore the health of our local land and waters with help from volunteers in the Puget Sound basin.^[26]

Sweden will stop salmon fishing in Baltic Sea in 2013 to protect it.^[27]

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