Claim: Literally lousy: Parasite plagues world salmon industry.
Verdict: SUPPORTS

Retrieved passages:
title: Fish disease and parasites
text: Adult salmon may survive otherwise critical numbers of sea lice, but small, thin-skinned juvenile salmon migrating to sea are highly vulnerable. On the Pacific coast of Canada, the louse-induced mortality of pink salmon in some regions is commonly over 80%. In 1972, Gyrodactylus salaris, also called salmon fluke, a monogenean parasite, spread from Norwegian hatcheries to wild salmon, and devastated some wild salmon populations. In 1984, infectious salmon anemia (ISAv) was discovered in Norway in an Atlantic salmon hatchery. Eighty percent of the fish in the outbreak died. ISAv, a viral disease, is now a major threat to the viability

title: Sea louse
text: salmonis" characterized by epithelial hyperplasia and inflammation. This results in rejection of the parasite within the first week of infection in these species of salmonids. Heavy infections of farmed Atlantic salmon and wild sockeye salmon ("Oncorhynchus nerka") by "L. salmonis" can lead to deep lesions, particularly on the head region, even exposing the skull. Some evidence indicates that sea lice flourishing on salmon farms can spread to nearby wild juvenile salmon and devastate these populations. Sea lice, particularly "L. salmonis" and various "Caligus" species, including "C. clemensi" and "C. rogercresseyi", can cause deadly infestations of both farm-grown and wild salmon.

title: Salmon louse
text: Salmon louse The salmon louse, Lepeophtheirus salmonis, is a species of copepod in the genus "Lepeophtheirus". It is a sea louse, a parasite living mostly on salmon, particularly on Pacific and Atlantic salmon and sea trout, but is also sometimes found on the three-spined stickleback. It lives off the mucus, skin and blood of the fish. They are natural marine parasites of fish such as adult salmon. Once detached they can be blown by wind across the surface of the sea, like plankton. When they encounter a suitable marine fish host they may adhere themselves to the skin, fins, the

title: Sea louse
text: been a condition of tenure license for farm operators. Many sea louse species are specific with regard to host genera, for example "L. salmonis" which has high specificity for salmonids, including the widely farmed Atlantic salmon ("Salmo salar"). "Lepeophtheirus salmonis" can parasitize other salmonids to varying degrees, including brown trout (sea trout: "Salmo trutta"), Arctic char ("Salvelinus alpinus"), and all species of Pacific salmon. In the case of Pacific salmon, coho, chum, and pink salmon ("Oncorhynchus kisutch", "O. keta", and "O. gorbuscha", respectively) mount strong tissue responses to attaching "L. salmonis", which lead to rejection within the first week of

title: Salmon louse
text: attached to the abdomen. The salmon louse uses its feet to move around on the host or to swim from one host to another. This parasite is one of the major threats to salmon farmers. Salmon are stocked usually for a 14 - 18 month cycle. Salmon farms are an unusual, but ideal environment for the sea lice to breed. The infestations of sea lice in salmon farms increases the number of lice in the rest of the surrounding water dramatically if the eggs from the gravid louse are allowed to disperse. Sea lice can also affect juvenile salmon while

title: Diseases and parasites in salmon
text: concentrations of sea lice; when exposed in river estuaries containing large numbers of open-net farms, many young wild salmon are infected, and do not survive as a result. Adult salmon may survive otherwise critical numbers of sea lice, but small, thin-skinned juvenile salmon migrating to sea are highly vulnerable. On the Pacific coast of Canada, the louse-induced mortality of pink salmon in some regions is commonly over 80%. In 1972, "Gyrodactylus", a monogenean parasite, spread from Norwegian hatcheries to wild salmon, and devastated some wild salmon populations. Enteric redmouth disease is a bacterial infection of freshwater and marine fish caused

title: Salmon louse
text: £300m in control efforts. In small numbers, salmon lice cause little damage to a fish although if populations increase on a fish, this can lead to death. The parasites can cause physical damage to the fish's fins, skin erosion, constant bleeding, and open wounds creating pathways for other pathogens. The sea lice may also act as a vector for diseases between wild and farmed salmon. These copepod vectors has caused infectious salmon anemia (ISA) along the Atlantic coast. An outbreak of ISA occurred in Chile during 2007 where it spread quickly from one farm to another, destroying the salmon farms.

title: Salmon louse
text: salmon from the rivers migrating to the ocean if on the way they pass by fish farms, the early stage and mature stages of sea lice may attaches onto them as well. These young salmon are smaller than a size of a key and still developing. When sea lice attach to the young salmon they can kill them. The Salmon louse currently infests nearly half of Scotland’s salmon farms. In 2016 Guardian news stated that the lice killed thousands of tonnes of farmed fish, caused skin lesions and secondary infections in millions more, and cost the Scottish salmon industry around

title: Sea louse
text: ectoparasites of farmed and wild Atlantic salmon. Several antiparasitic drugs have been developed for control purposes. "L. salmonis" is the best understood in the areas of its biology and interactions with its salmon host. "Caligus rogercresseyi" has become a major parasite of concern on salmon farms in Chile, and studies are under way to gain a better understanding of the parasite and the host-parasite interactions. Recent evidence is also emerging that "L. salmonis" in the Atlantic has sufficient genetic differences from "L. salmonis" from the Pacific to suggest that Atlantic and Pacific "L. salmonis" may have independently co-evolved with Atlantic

title: Salmon louse
text: combat salmon lice infection. The intensity of inflammatory response controls how fast the parasites are rejected from the body. Intensity is determined by recognition of and regulation by salmon lice secretory/excretory products (SEP), which includes proteases and prostaglandin E2. The marine parasite secretes SEP into the damaged skin of the salmon which inhibits proteolytic activity. Proteolytic activity increases the amount of host peptides and amino acids that can be used as a source of nutrition and lowers the intensity of inflammatory responses. Salmon louse The salmon louse, Lepeophtheirus salmonis, is a species of copepod in the genus "Lepeophtheirus". It is

title: Sea louse
text: lice, and Krkosek "et al." have claimed that on the Pacific coast of Canada the louse-induced mortality of pink salmon in some regions is over 80%. A few studies indicated no long-term damage to fish stocks in some locations, and a population decline in wild salmon that occurred in 2002 was caused by "something other than sea lice". However, the repeated epizootics of lice on wild fish have only occurred in areas with salmon farms in Ireland, Scotland, Norway, British Columbia, and Chile. Field sampling of copepodids, and hydrographic and population models, show how "L. salmonis" from farms can cause

title: Diseases and parasites in salmon
text: as Fraser, Skeena, Nass and from mainland coastal streams in the southern half of B.C. "are more likely to have a low prevalence of infection." The report also states "It should be stressed that "Henneguya", economically deleterious though it is, is harmless from the view of public health. It is strictly a fish parasite that cannot live in or affect warm blooded animals, including man". According to Klaus Schallie, Molluscan Shellfish Program Specialist with the Canadian Food Inspection Agency, ""Henneguya salminicola" is found in southern B.C. also and in all species of salmon. I have previously examined smoked chum salmon

title: Fish disease and parasites
text: In crowded net pens they can become epidemics. Diseases and parasites also transfer from farmed to wild salmon populations. A recent study in British Columbia links the spread of parasitic sea lice from river salmon farms to wild pink salmon in the same river." The European Commission (2002) concluded “The reduction of wild salmonid abundance is also linked to other factors but there is more and more scientific evidence establishing a direct link between the number of lice-infested wild fish and the presence of cages in the same estuary.” It is reported that wild salmon on the west coast of

title: Salmon
text: conducted, stocks from the middle and upper reaches of large river systems in British Columbia such as Fraser, Skeena, Nass and from mainland coastal streams in the southern half of B.C., "are more likely to have a low prevalence of infection." The report also states, "It should be stressed that "Henneguya", economically deleterious though it is, is harmless from the view of public health. It is strictly a fish parasite that cannot live in or affect warm blooded animals, including man". According to Klaus Schallie, Molluscan Shellfish Program Specialist with the Canadian Food Inspection Agency, ""Henneguya salminicola" is found in

title: Infectious salmon anemia virus
text: salmonis" sea louse, a small crustacean parasite that attacks the protective mucus, scales and skin of the salmon, can carry the virus passively on its surface and in its digestive tract. Under laboratory conditions "Lepeophtheirus salmonis" can passively transfer ISA. It is not known whether the ISA virus can reproduce itself in the sea louse, although this is a possibility as viruses can use secondary vectors for transmission, for example Arboviruses such as dengue fever, West Nile virus, or African swine fever virus. Clinical signs and pathology may suggest infection. Viral identification is possible using immunofluorescence and PCR. There is

title: Sea louse
text: stages can be transported tens of kilometres from their source. The source of "L. salmonis" infections when salmon return from fresh water has always been a mystery. Sea lice die and fall off anadromous fish such as salmonids when they return to fresh water. Atlantic salmon return and travel upstream in the fall to reproduce, while the smolts do not return to salt water until the next spring. Pacific salmon return to the marine nearshore starting in June, and finish as late as December, dependent upon species and run timing, whereas the smolts typically outmigrate starting in April, and ending

title: Fish disease and parasites
text: the spawning stream. When juvenile salmon out-migrate to the Pacific Ocean, the second host releases a stage infective to salmon. The parasite is then carried in the salmon until the next spawning cycle. The myxosporean parasite that causes whirling disease in trout, has a similar lifecycle. However, as opposed to whirling disease, the "Henneguya" infestation does not appear to cause disease in the host salmon — even heavily infected fish tend to return to spawn successfully. According to Dr. Kieser, a lot of work on "Henneguya salminicola" was done by scientists at the Pacific Biological Station in Nanaimo in the

title: Diseases and parasites in salmon
text: classified on List One of the European Commission’s fish health regime. Amongst other measures, this requires the total eradication of the entire fish stock should an outbreak of the disease be confirmed on any farm. ISAv seriously affects salmon farms in Chile, Norway, Scotland and Canada, causing major economic losses to infected farms. As the name implies, it causes severe anemia of infected fish. Unlike mammals, the red blood cells of fish have DNA, and can become infected with viruses. The fish develop pale gills, and may swim close to the water surface, gulping for air. However, the disease can

title: Fish farming
text: sea are highly vulnerable. On the Pacific coast of Canada, the louse-induced mortality of pink salmon in some regions is commonly over 80%. A 2008 meta-analysis of available data shows that salmon farming reduces the survival of associated wild salmon populations. This relationship has been shown to hold for Atlantic, steelhead, pink, chum, and coho salmon. The decrease in survival or abundance often exceeds 50%. Diseases and parasites are the most commonly cited reasons for such decreases. Some species of sea lice have been noted to target farmed coho and Atlantic salmon. Such parasites have been shown to have an

title: Salmon louse
text: gills of the fish, and feeding off the mucus or skin. Sea lice only affect fish and are not harmful towards humans. Salmon lice are natural ectoparasites of salmon, in the 1980s high levels of salmon lice were observed on Pink salmon smolts. Salmon lice are found in Pacific and Atlantic Oceans, they infect Pink salmon, Atlantic salmon, and Chum salmon. There has been some research on the problems caused by this species in aquaculture, but little is known about the salmon louse's life in nature. It has been shown, however, that salmon louse infections in fish farming facilities can