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27-436: Pollan may refer to: Pollan (fish) , or Irish pollan Carolyn Pollan (1937–2021), American politician Carlos Pollán (born 1966), Spanish handball player and politician Michael Pollan (born 1955), American author Tracy Pollan (born 1960), American actress See also [ edit ] Polan (disambiguation) Polian (disambiguation) Topics referred to by

54-749: A 1949 journal article: 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 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 have their spawning ground in southern Norway , their feeding ground in Iceland 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

81-824: A forage fish of the smelt family found in the Atlantic and Arctic oceans. In summer, they graze on dense swarms of plankton at the edge of the ice shelf. Larger capelin also eat krill and other crustaceans . The capelin move inshore in large schools to spawn and migrate in spring and summer to feed in plankton rich areas between Iceland , Greenland and Jan Mayen . The migration is affected by ocean currents . Around Iceland maturing capelin make large northward feeding migrations in spring and summer. The return migration takes place in September to November. The spawning migration starts north of Iceland in December or January. The diagram on

108-580: 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. Since prehistoric times humans have exploited certain anadromous fishes during their migrations into freshwater streams, when they are more vulnerable to capture. Societies dating to

135-450: Is a euryhaline 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 move to the north and south at different times of year following temperature gradients. The patterns of migration are of great interest to the fishing industry. Movements of fish in fresh water also occur; often

162-451: Is different from Wikidata All article disambiguation pages All disambiguation pages Pollan (fish) The pollan or Irish pollan ( Coregonus pollan or Coregonus autumnalis ) is a freshwater whitefish known only from five Irish lakes, Lough Neagh , Lower Lough Erne , Lough Ree , Lough Derg and Lough Allen . The pollan faces competition from introduced species such as pike , roach and zebra mussel , and

189-771: The American eel and the European eel which migrate huge distances from freshwater rivers to spawn in the Sargasso Sea , 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 species is the bull shark , which lives in Lake Nicaragua of Central America and the Zambezi River of Africa. Both these habitats are fresh water, yet bull sharks will also migrate to and from

216-581: The Millingstone Horizon are known which exploited the anadromous fishery of Morro Creek and other Pacific coast estuaries . In Nevada the Paiute tribe has harvested migrating Lahontan cutthroat trout along the Truckee River 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

243-963: The United Nations Convention on the Law of the Sea (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 and tuna-like species ( albacore , bluefin , bigeye tuna , skipjack , yellowfin , blackfin , little tunny , southern bluefin and bullet ), wahoo , pomfret , marlin , sailfish , swordfish , saury and oceangoing sharks , dolphins and other cetaceans . These high trophic level 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

270-845: The high seas . Transboundary stock range in the EEZs of at least two countries. A stock can be both transboundary and straddling. 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 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 . Some of

297-444: The 200-nautical-mile (370-kilometre) exclusive economic zones and in the high seas outside these zones. They are pelagic 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 as well as in

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324-569: The Irish pollan are usually classified within the species Coregonus autumnalis . That is a widespread anadromous whitefish which inhabits coastal waters and rivers of Arctic Siberia , Alaska , and Canada and is there known as the Arctic cisco or Siberian omul. C. autumnalis is not distributed elsewhere in northwestern Europe, and the pollan are often given a status of subspecies as Coregonus autumnalis pollan . These classifications are based on

351-737: The Truckee can support suitable populations of the Lahontan cutthroat trout. Because salmonids live an anadromous lifestyle, they encounter a larger range of viruses 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 that have totally lost their Mx genes. A study

378-552: The best-known anadromous fishes are the Pacific salmon species, such as Chinook (king), coho (silver), chum (dog), pink (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 ladders in dams to enable

405-615: The close genetic similarity of the Arctic and Irish whitefish populations. By IUCN and in the FishBase , the Irish pollan is, however, listed as a distinct fish species Coregonus pollan . Unlike its Arctic relatives, the Irish pollan does not migrate to the sea. Anadromous 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

432-546: The fact that the fish cannot identify their own offspring and moving in this way prevents cannibalism . Some species have been described by the United Nations Convention on the Law of the Sea as highly migratory species. These are large pelagic fish that move in and out of the exclusive economic zones of different nations, and these are covered differently in the treaty from other fish. Salmon and striped bass are well-known anadromous fish, and freshwater eels are catadromous fish that make large migrations. The bull shark

459-402: The fish swim upriver to spawn, and these traditional movements are increasingly being disrupted by the building of dams. 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. George S. Myers coined the following terms in

486-521: 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 , migrate north and south annually, following temperature variations in

513-551: The ocean. These are of great importance to fisheries . 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

540-534: The populations rely on restocking for survival. The pollan populations are threatened by ecosystem changes such as eutrophication and increases in species, including pike , roach and zebra mussel . Only the population of Lough Neagh in Northern Ireland remains abundant and supports a small commercial fishery. The other Northern Irish population in Lough Erne has severely declined. The Lough Allen population

567-538: The right shows the main spawning grounds and larval 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. The term highly migratory species (HMS) has its origins in Article 64 of

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594-488: The salmon to get past. Other examples of anadromous fishes are sea trout , three-spined stickleback , sea lamprey and shad . Several Pacific salmon (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

621-463: The same term [REDACTED] This disambiguation page lists articles associated with the title Pollan . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Pollan&oldid=1165723358 " Categories : Disambiguation pages Disambiguation pages with surname-holder lists Hidden categories: Short description

648-424: The sea and migrate into fresh water to spawn ; and catadromous , in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Movements are associated with ocean currents and with the availability of food in different areas at different times of year. The migratory movements may partly be linked to

675-590: The tail fin deeply forked. The different species are difficult to tell apart unless the lake from which they originated is known. This species grows to an average length of 9 to 10 in (22.9 to 25.4 cm) and a weight of 6 ounces (170 g). The Irish pollan is a shoaling species. The diet consists small crustaceans and insect larvae. Breeding takes place in November and December, with spawning taking place over hard ground in deep water. In scientific literature and national biodiversity and conservation assessments,

702-459: Was only confirmed for the first time in 2006. Other populations rely on stocking for their survival. The Irish pollan and other members of the Coregonus genus are very like herrings in appearance but the presence of an adipose fin distinguishes them. The mouth is relatively small and the teeth are deciduous and very small. The scales are of moderate size, the dorsal fin is of moderate length and

729-452: 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

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