
Fish migration is
mass relocation by
fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
from one area or
body of water
A body of water or waterbody is any significant accumulation of water on the surface of Earth or another planet. The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rare ...
to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear.
Fish migrations involve movements of
schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to
spawn
Spawn or spawning may refer to:
* Spawning, the eggs and sperm of aquatic animals
Arts, entertainment and media
* Spawn (character), a fictional character in the comic series of the same name and in the associated franchise
** ''Spawn: Armageddon' ...
; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn.
Marine
forage fish
Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons (i.e. planktivores) and other small aquatic organisms (e.g. krill). They are in turn preyed upon by various predators including larger fish, seabirds ...
often make large migrations between their spawning, feeding and nursery grounds. Their movements are associated with ocean currents and with the availability of food in different areas at different times of the year. The migratory movements may partly be linked to the fact that the fish cannot identify their own offspring and moving in this way prevents
cannibalism
Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is also well document ...
. Some species have been described by the
United Nations Convention on the Law of the Sea
The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international treaty that establishes a legal framework for all marine and maritime activities. , 169 sov ...
as highly migratory species. These are large
pelagic fish
Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs. ...
that move in and out of the
exclusive economic zones
An exclusive economic zone (EEZ), as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine resources, including e ...
of different nations, and these are covered differently in the treaty from other fish.
Salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...
and
striped bass
The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has ...
are well-known anadromous fish, and freshwater
eels are catadromous fish that make large migrations. The
bull shark
The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in riv ...
is a
euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water.
The green crab ('' Carcinus m ...
species that moves at will from fresh to salt water, and many marine fish make a
diel vertical migration, rising to the surface to feed at night and sinking to lower layers of the ocean by day. Some fish such as
tuna
A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...
move to the north and south at different times of year following temperature gradients. The fish with the longest freshwater migration is the
dourada catfish, which travels up the
Amazon River. The patterns of migration are of great interest to the fishing industry. Movements of fish in fresh water also occur; often the fish swim upriver to spawn, and these traditional movements are increasingly being disrupted by the building of dams.
Classification

As with various other aspects of fish life, zoologists have developed empirical classifications for fish migrations.
The first two following terms have been in long-standing wide usage, while others are of more recent coinage.
* ''Anadromous'' – fish that migrate from the sea up ( and ) into fresh water to spawn, such as
salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...
,
striped bass
The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has ...
,
and the
sea lamprey
The sea lamprey (''Petromyzon marinus'') is a parasitic lamprey native to the Northern Hemisphere. It is sometimes referred to as the "vampire fish".
It was likely introduced to the Great Lakes region through the Erie Canal in 1825 and the Wel ...
[Silva, S., Araújo, M. J., Bao, M., Mucientes, G., & Cobo, F. (2014). "The haematophagous feeding stage of anadromous populations of sea lamprey Petromyzon marinus: low host selectivity and wide range of habitats". ''Hydrobiologia'', 734(1), 187–199.]
* ''Catadromous'' – fish that migrate from fresh water down (Greek: and ) into the sea to spawn, such as
eels
George S. Myers coined the following terms in a 1949 journal article:
* ''Diadromous'' – ''all'' fish that migrate between the sea and fresh water. Like the two aforementioned, well-known terms, ''diadromous'' was formed from
Classical Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archa ...
( and ).
* ''Amphidromous'' – fish that migrate from fresh water to the sea, or vice versa, but not for the purpose of breeding. Instead they enter saltwater or freshwater as larvae, where they will grow into juveniles before returning to the habitat they originally came from and stay there for the rest of their life, growing into sexually mature adults.
[Investigating Diadromy in Fishes and Its Loss in an -Omics Era](_blank)
/ref>
* ''Potamodromous'' – fish whose migrations occur wholly within fresh water
* ''Oceanodromous'' – fish that live and migrate wholly in the sea
Although these classifications originated for fish, they can apply, in principle, to any aquatic organism.
List of diadromous orders and families, and the number of known species:
Forage fish
Forage fish
Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons (i.e. planktivores) and other small aquatic organisms (e.g. krill). They are in turn preyed upon by various predators including larger fish, seabirds ...
often make great migrations between their spawning, feeding and nursery grounds. Schools of a particular stock usually travel in a triangle between these grounds. For example, one stock of herrings has their spawning ground in southern Norway
Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...
, their feeding ground in Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
, and their nursery ground in northern Norway. Wide triangular journeys such as these may be important because forage fish, when feeding, cannot distinguish their own offspring.
Capelin are a forage fish of the smelt family found in the Atlantic
The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...
and Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
oceans. In summer, they graze on dense swarms of plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...
at the edge of the ice shelf. Larger capelin also eat krill
Krill ''(Euphausiids)'' (: krill) are small and exclusively marine crustaceans of the order (biology), order Euphausiacea, found in all of the world's oceans. The name "krill" comes from the Norwegian language, Norwegian word ', meaning "small ...
and other crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
s. The capelin move inshore in large schools to spawn and migrate in spring and summer to feed in plankton rich areas between Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
, Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...
and Jan Mayen
Jan Mayen () is a Norway, Norwegian volcanic island in the Arctic Ocean with no permanent population. It is long (southwest-northeast) and in area, partly covered by glaciers (an area of around the Beerenberg volcano). It has two parts: la ...
. The migration is affected by ocean current
An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, sh ...
s. Around Iceland, maturing capelin make large northward feeding migrations in spring and summer. The return migration takes place from September to November. The spawning migration starts north of Iceland in December or January.
The diagram on the right shows the main spawning
Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...
grounds and larval
A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...
drift routes. Capelin on the way to feeding grounds is coloured green, capelin on the way back is blue, and the breeding grounds are red.
In a paper published in 2009, researchers from Iceland recount their application of an interacting particle model to the capelin stock around Iceland, successfully predicting the spawning migration route for 2008.
Highly migratory species
The term highly migratory species (HMS) has its origins in Article 64 of the United Nations Convention on the Law of the Sea
The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international treaty that establishes a legal framework for all marine and maritime activities. , 169 sov ...
(UNCLOS). The Convention does not provide an operational definition of the term, but in an annex (UNCLOS Annex 1) lists the species considered highly migratory by parties to the convention. The list includes: tuna
A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...
and tuna-like species (albacore
The albacore (''Thunnus alalunga''), known also as the longfin tuna, is a species of tuna of the order Scombriformes. It is found in temperate and tropical waters across the globe in the epipelagic and mesopelagic zones. There are six distinct ...
, bluefin, bigeye tuna
The bigeye tuna (''Thunnus obesus'') is a species of true tuna of the genus ''Thunnus'', belonging to the wider mackerel family (biology), family Scombridae. In Hawaiian language, Hawaiian, it is one of two species known as ahi, the other being t ...
, skipjack, yellowfin, blackfin
Blackfin is a family of 16-/32-bit microprocessors developed, manufactured and marketed by Analog Devices. The processors have built-in, fixed-point digital signal processor (DSP) functionality performed by 16-bit multiply–accumulates (MA ...
, little tunny, southern bluefin and bullet
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constru ...
), wahoo
The wahoo (''Acanthocybium solandri'') is a scombrid fish found worldwide in tropical and subtropical seas. In Hawaii, the wahoo is known as ono. The species is sometimes called hoo in the United States. It is best known to sports fishermen, a ...
, pomfret, marlin
Marlins are fish from the family Istiophoridae, which includes between 9 and 11 species, depending on the taxonomic authority.
Name
The family's common name is thought to derive from their resemblance to a sailor's marlinspike.
Taxonomy
T ...
, sailfish
The sailfish is one or two species of marine fish in the genus ''Istiophorus'', which belong to the family Istiophoridae ( marlins). They are predominantly blue to gray in colour and have a characteristically large dorsal fin known as the ...
, swordfish
The swordfish (''Xiphias gladius''), also known as the broadbill in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are the sole member of the Family (biology), family Xiphiidae. They ...
, saury
The saury (''Cololabis adocetus'') is a species of fish that is a member of the family Scomberesocidae, or the saury family. It is widespread in the Eastern Pacific in the surface waters, typically remaining in the top 50 centimeters of the water ...
and oceangoing shark
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...
s, dolphin
A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...
s and other cetaceans
Cetacea (; , ) is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively c ...
.
These high trophic level
The trophic level of an organism is the position it occupies in a food web. Within a food web, a food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the ...
oceanodromous species undertake migrations of significant but variable distances across oceans for feeding, often on forage fish, or reproduction, and also have wide geographic distributions. Thus, these species are found both inside the exclusive economic zone
An exclusive economic zone (EEZ), as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine natural resource, reso ...
s and in the high seas
The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regiona ...
outside these zones. They are pelagic
The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...
species, which means they mostly live in the open ocean and do not live near the sea floor, although they may spend part of their life cycle in nearshore waters.
Highly migratory species can be compared with straddling stock and transboundary stock. Straddling stock range both within an EEZ
An exclusive economic zone (EEZ), as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine natural resource, reso ...
as well as in the high seas
The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regiona ...
. Transboundary stock range in the EEZs of at least two countries. A stock can be both transboundary and straddling.FAO
The Food and Agriculture Organization of the United Nations; . (FAO) is a List of specialized agencies of the United Nations, specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition ...
(2007
Report of the FAO workshop on vulnerable ecosystems and destructive fishing in deep sea fisheries
Rome, Fisheries Report No. 829
HTML
/ref>
It can be challenging to determine the population structure of highly migratory species using physical tagging. Traditional genetic markers such as short-range PCR products, microsatellites and SNP-arrays have struggled to identify population structure and distinguish fish stocks
Fish stocks are population, subpopulations of a particular species of fish, for which intrinsic parameters (growth, recruitment, mortality and fishing mortality) are traditionally regarded as the significant factors determining the Population ...
from separate ocean basins. However, population genomic research using RAD sequencing in yellowfin tuna, albacore, and wahoo has been able to distinguish populations from different ocean basins and reveal fine-scale population structure. Similar population genomics methods have also provided improved insight towards population structure in striped marlin
The striped marlin (''Tetrapturus audax'', also ''Kajikia audax'') is a species of marlin found globally in tropical to temperate oceans not far from the surface. It is a desirable commercial and game fish, although conservation measures are in p ...
.
Other examples
Some of the best-known anadromous fishes are the Pacific salmon
''Oncorhynchus'', from Ancient Greek ὄγκος (''ónkos''), meaning "bend", and ῥύγχος (''rhúnkhos''), meaning "snout", is a genus of ray-finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributarie ...
species, such as Chinook (king), coho COHO, short for Coherent Oscillator, is a technique used with radar systems based on the cavity magnetron to allow them to implement a moving target indicator display. Because the signals are only coherent when received, not transmitted, the concept ...
(silver), chum (dog), pink
Pink is a pale tint of red, the color of the Dianthus plumarius, pink flower. It was first used as a color name in the late 17th century. According to surveys in Europe and the United States, pink is the color most often associated with charm, p ...
(humpback) and sockeye (red) salmon. These salmon hatch in small freshwater streams. From there they migrate to the sea to mature, living there for two to six years. When mature, the salmon return to the same streams where they were hatched to spawn. Salmon are capable of going hundreds of kilometers upriver, and humans must install fish ladder
A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon, is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as mov ...
s in dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...
s to enable the salmon to get past. Other examples of anadromous fishes are sea trout
Sea trout is the common name usually applied to anadromous (sea-run) forms of brown trout (''Salmo trutta''), and is often referred to as ''Salmo trutta'' morpha ''trutta''. Other names for anadromous brown trout are bull trout, sewin (Wales ...
, three-spined stickleback
The three-spined stickleback (''Gasterosteus aculeatus'') is a fish native to most inland and coastal waters north of 30°N. It has long been a subject of scientific study for many reasons. It shows great morphological variation throughout its ra ...
, sea lamprey
The sea lamprey (''Petromyzon marinus'') is a parasitic lamprey native to the Northern Hemisphere. It is sometimes referred to as the "vampire fish".
It was likely introduced to the Great Lakes region through the Erie Canal in 1825 and the Wel ...
and shad
The Alosidae, or the shads, are a family (biology), family of clupeiform fishes. The family currently comprises four genera worldwide, and about 32 species.
The shads are Pelagic fish, pelagic (open water) schooling fish, of which many are anadr ...
.
Several Pacific salmon
''Oncorhynchus'', from Ancient Greek ὄγκος (''ónkos''), meaning "bend", and ῥύγχος (''rhúnkhos''), meaning "snout", is a genus of ray-finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributarie ...
(Chinook, coho and Steelhead) have been introduced into the US Great Lakes, and have become potamodromous, migrating between their natal waters to feeding grounds entirely within fresh water.
Remarkable catadromous migrations are made by freshwater eels. Examples are the American eel
The American eel (''Anguilla rostrata'') is a facultative catadromous eel found on the eastern coast of North America. Anguillidae, Freshwater eels are fish belonging to the Elopomorpha, elopomorph superorder, a group of Phylogenetics, phylogen ...
and the European eel which migrate huge distances from freshwater rivers to spawn in the Sargasso Sea
The Sargasso Sea () is a region of the Atlantic Ocean bounded by four currents forming an ocean gyre. Unlike all other regions called seas, it is the only one without land boundaries. It is distinguished from other parts of the Atlantic Oc ...
, and whose subsequent larvae can drift in currents for months and even years before returning to their natal rivers and streams as glass eels or elvers.
An example of a euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water.
The green crab ('' Carcinus m ...
species is the bull shark
The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in riv ...
, which lives in Lake Nicaragua
Lake Nicaragua or Cocibolca or Granada (, , or ) is a freshwater lake in Nicaragua. Of tectonic origin and with an area of , it is the largest fresh water lake in Central America, the List of lakes by area, 19th largest lake in the world (by are ...
of Central America and the Zambezi River
The Zambezi (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than half of t ...
of Africa. Both these habitats are fresh water, yet bull sharks will also migrate to and from the ocean. Specifically, Lake Nicaragua bull sharks migrate to the Atlantic Ocean and Zambezi bull sharks migrate to the Indian Ocean.
Diel vertical migration is a common behavior; many marine species move to the surface at night to feed, then return to the depths during daytime.
A number of large marine fishes, such as the tuna
A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...
, migrate north and south annually, following temperature variations in the ocean. These are of great importance to fisheries
Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...
.
Freshwater (potamodromous) fish migrations are usually shorter, typically from lake to stream or vice versa, for spawning purposes. However, potamodromous migrations of the endangered Colorado pikeminnow of the Colorado River system can be extensive. Migrations to natal spawning grounds can easily be 100 km, with maximum distances of 300 km reported from radiotagging studies. Colorado pikeminnow migrations also display a high degree of homing and the fish may make upstream or downstream migrations to reach very specific spawning locations in whitewater canyons.
Sometimes fish can be dispersed by birds that eat fish eggs. They carry eggs in the digestive tracts and then deposit them in their faeces in a new place. The survival rate for fish eggs that have passed through a bird's digestive tract is low.
Historic exploitation
Since prehistoric
Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use o ...
times humans have exploited certain anadromous fishes during their migrations into freshwater streams, when they are more vulnerable to capture. Societies dating to the Millingstone Horizon are known which exploited the anadromous fishery of Morro Creek and other Pacific coast
Pacific coast may be used to reference any coastline that borders the Pacific Ocean.
Geography Americas North America
Countries on the western side of North America have a Pacific coast as their western or south-western border. One of th ...
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...
. In Nevada
Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...
the Paiute
Paiute (; also Piute) refers to three non-contiguous groups of Indigenous peoples of the Great Basin. Although their languages are related within the Numic group of Uto-Aztecan languages, these three languages do not form a single subgroup and th ...
tribe has harvested migrating Lahontan cutthroat trout
Lahontan cutthroat trout'','' ''Oncorhynchus henshawi'',Markle, D. (2018). An interim classification of the cutthroat trout complex, Oncorhynchus clarkii Sensu Lato, with comments on nomenclature. In Trotter P., Bisson P., Schultz L., & Roper B. ...
along the Truckee River
The Truckee River is a river in the U.S. states of California and Nevada. The river flows northeasterly and is long.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed October 20, 2012 Th ...
since prehistoric times. This fishing practice continues to current times, and the U.S. Environmental Protection Agency has supported research to assure the water quality in the Truckee can support suitable populations of the Lahontan cutthroat trout.
Myxovirus genes
Because salmonids live an anadromous lifestyle, they encounter a larger range of viruses
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almo ...
from both freshwater and marine ecosystems. Myxovirus resistance (Mx) proteins are part of a GTP-ase family that aid in viral immunity, and previously, rainbow trout ('' Oncorhynchus mykiss'') had been shown to possess three different Mx genes to aid in viral defence in both environments. The number of Mx genes can differ among species of fish, with numbers ranging from 1 to 9 and some outliers like Gadiformes
Gadiformes , also called the Anacanthini, are an order of ray-finned fish that include the cod, hakes, pollock, haddock, burbot, rocklings and moras, many of which are food fish of major commercial value. They are mostly marine fish found thr ...
that have totally lost their Mx genes. A study was performed by Wang et al. (2019) to identify more potential Mx genes that resided in rainbow trout. An additional six Mx genes were identified in that study, now named Mx4-9. They also concluded that the trout Mx genes were "differentially expressed constitutively in tissues" and that this expression is increased during development. The Mx gene family is expressed at high levels in the blood and intestine during development, suggesting they are a key to immune defense for the growing fish. The idea that these genes play an important role in development against viruses suggests they are critical in the trout's success in an anadromous lifestyle.
See also
*
*
*
*
*
*
*
Notes
References
* Blumm, M (2002
''Sacrificing the Salmon: A Legal and Policy History of the Decline of Columbia Basin Salmon''
Bookworld Publications.
* Bond, C E (1996) ''Biology of Fishes'', 2nd ed. Saunders, pp. 599–605.
* Hogan, C M (2008
''Morro Creek''
The Megalithic Portal, ed. by A. Burnham
in Carolsfield J, Harvey B, Ross C and Anton Baer A (2004) ''Migratory Fishes of South America'' World Fisheries Trust/World Bank/IDRC. .
Further reading
* Ueda H and Tsukamoto K (eds) (2013
''Physiology and Ecology of Fish Migration''
CRC Press. .
External links
* United Nations
The United Nations (UN) is the Earth, global intergovernmental organization established by the signing of the Charter of the United Nations, UN Charter on 26 June 1945 with the stated purpose of maintaining international peace and internationa ...
Introduction to the Convention on Migratory Species
Living North Sea
– International project on tackling fish migration problems in the North Sea Region
Fish Migration Network
– Worldwide network of specialist working on the theme fish migration
{{DEFAULTSORT:Fish Migration
Ichthyology
Aquatic ecology
Animal migration
Articles containing video clips