Salmon is the common name for several commercially important species of euryhaline ray-finned fish from the genera Salmo and Oncorhynchus of the family Salmonidae, native to tributaries of the North Atlantic (Salmo) and North Pacific (Oncorhynchus) basins. Other closely related fish in the same family include trout, char, grayling, whitefish, lenok and taimen, all coldwater fish of the subarctic and cooler temperate regions with some sporadic endorheic populations in Central Asia.
Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmon, trout, char, graylings, freshwater whitefishes, taimens and lenoks, all coldwater mid-level predatory fish that inhabit the subarctic and cool temperate waters of the Northern Hemisphere. The Atlantic salmon, whose Latin name became that of its genus Salmo, is also the eponym of the family and order names.
Fish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environments. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species produced in fish farming are carp, catfish, salmon and tilapia.
The rainbow trout is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead is an anadromous (sea-run) form of the coastal rainbow trout(O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.
Myxobolus cerebralis is a myxosporean parasite of salmonids that causes whirling disease in farmed salmon and trout and also in wild fish populations. It was first described in rainbow trout in Germany in 1893, but its range has spread and it has appeared in most of Europe, the United States, South Africa, Canada and other countries from shipments of cultured and wild fish. In the 1980s, M. cerebralis was found to require a tubificid oligochaete to complete its life cycle. The parasite infects its hosts with its cells after piercing them with polar filaments ejected from nematocyst-like capsules. This infects the cartilage and possibly the nervous tissue of salmonids, causing a potentially lethal infection in which the host develops a black tail, spinal deformities, and possibly more deformities in the anterior part of the fish.
Ceratonova shasta is a myxosporean parasite that infects salmonid fish on the Pacific coast of North America. It was first observed at the Crystal Lake Hatchery, Shasta County, California, and has now been reported from Idaho, Oregon, Washington, British Columbia and Alaska.
Oncorhynchus is a genus of ray-finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributaries of the North Pacific basin. The genus contains twelve extant species, namely six species of Pacific salmon and six species of Pacific trout, all of which are migratory mid-level predatory fish that display natal homing and semelparity.
Tetracapsuloides bryosalmonae is a myxozoan parasite of salmonid fish. It is the only species currently recognized in the monotypic genus Tetracapsuloides. It is the cause of proliferative kidney disease (PKD), one of the most serious parasitic diseases of salmonid populations in Europe and North America that can result in losses of up to 90% in infected populations.
The Ichthyosporea are a small group of Opisthokonta in Eukaryota, mostly parasites of fish and other animals.
Sea lice are copepods of the family Caligidae within the order Siphonostomatoida. They are marine ectoparasites that feed on the mucus, epidermal tissue, and blood of host fish. The roughly 559 species in 37 genera include around 162 Lepeophtheirus and 268 Caligus species.
A xenoma is a growth caused by various protists and fungi, most notably microsporidia. It can occur on numerous organisms; however is predominantly found on fish.
Infectious hematopoietic necrosis virus (IHNV), is a negative-sense single-stranded, bullet-shaped RNA virus that is a member of the Rhabdoviridae family, and from the genus Novirhabdovirus. It causes the disease known as infectious hematopoietic necrosis in salmonid fish such as trout and salmon. The disease may be referred to by a number of other names such as Chinook salmon disease, Coleman disease, Columbia River sockeye disease, Cultus Lake virus disease, Oregon sockeye disease, Sacramento River Chinook disease and sockeye salmon viral disease. IHNV is commonly found in the Pacific Coast of Canada and the United States, and has also been found in Europe and Japan. The first reported epidemics of IHNV occurred in the United States at the Washington and the Oregon fish hatcheries during the 1950s. IHNV is transmitted following shedding of the virus in the feces, urine, sexual fluids, and external mucus and by direct contact or close contact with the surrounding water. The virus gains entry into fish at the base of the fins.
The stone moroko, also known as the topmouth gudgeon, is a fish belonging to the Cyprinid family, native to Asia, but introduced and now considered an invasive species in Europe and North America. The fish's size is rarely above 8 cm and usually 2 to 7.5 cm long.
Nanophyetus salmincola is a food-borne intestinal trematode parasite prevalent on the Pacific Northwest coast. The species may be the most common trematode endemic to the United States.
Dermocystidium is a genus of cyst-forming, eukaryotic fish parasites, the causative agents of dermocystidiosis.
The aquaculture of salmonids is the farming and harvesting of salmonid fish under controlled conditions for both commercial and recreational purposes. Salmonids, along with carp and tilapia, are the three most important fish groups in aquaculture. The most commonly commercially farmed salmonid is the Atlantic salmon.
Like humans and other animals, fish suffer from diseases and parasites. Fish defences against disease are specific and non-specific. Non-specific defences include skin and scales, as well as the mucus layer secreted by the epidermis that traps microorganisms and inhibits their growth. If pathogens breach these defences, fish can develop inflammatory responses that increase the flow of blood to infected areas and deliver white blood cells that attempt to destroy the pathogens.
Bacterial cold water disease (BCWD) is a bacterial disease of freshwater fish, specifically salmonid fish. It is caused by the bacterium Flavobacterium psychrophilum, a psychrophilic, gram-negative rod-shaped bacterium of the family Flavobacteriaceae. This bacterium is found in fresh waters with the optimal growth temperature below 13 °C, and it can be seen in any area with water temperatures consistently below 15 °C. Salmon are the most commonly affected species. This disease is not zoonotic.
Diseases and parasites in salmon, trout and other salmon-like fishes of the family Salmonidae are also found in other fish species. The life cycle of many salmonids is anadromous, so such fish are exposed to parasites in fresh water, brackish water and saline water.
Piscirickettsia salmonis is the bacterial causative agent of piscirickettsiosis, an epizootic disease in salmonid fishes. It has a major impact on salmon populations, with a mortality rate of up to 90% in some species. The type strain, LF-89, is from Chile, but multiple strains exist, and some are more virulent than others. P. salmonis and piscrickettsiosis are present in various geographic regions from Europe to Oceania to South America, but the Chilean salmon farming industry has been particularly hard-hit. Different strategies of controlling the disease and farm-to-farm spread have been the subject of much research, but a significant amount is still unknown.
