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EveryFish

Between sea and river

Fish that migrate between salt and fresh water to breed, like salmon and hilsa. 35 fish on EveryFish so far.

Some fish move between the sea and fresh water to breed. Anadromous fish, such as salmon, hilsa, shad, many sturgeons and the sea lamprey, grow at sea and swim up rivers to spawn. Catadromous fish, such as freshwater eels, do the opposite, living in rivers and travelling to the sea to spawn. These journeys can run to thousands of kilometres and link the ocean to the heart of the continents.

Journeys between waters

Pacific salmon return to the stream where they hatched, often finding it by smell, after years at sea. The hilsa enters the rivers of Bengal in the monsoon, and its run sets the fishing season in Bangladesh and West Bengal. European eels cross the Atlantic to the Sargasso Sea to spawn. Each of these fish has to rebuild its body's salt balance as it moves between salt and fresh water, a change controlled by hormones.

Blocked rivers

Migratory fish need open rivers. Dams, barrages and weirs block their way, and the Living Planet Index for migratory freshwater fish found an average fall of 76 per cent in monitored populations between 1970 and 2016. The Farakka Barrage cut the hilsa run up the Ganges, and dams on the Volga cut sturgeon from their spawning grounds. Fish ladders and lifts help some species, and removing old dams, as on the Elwha River in the United States, has let salmon return.

Famous between sea and river fish

Sockeye salmonThe great runs of AlaskaSea lampreyA jawless fish that spawns in rivers

Still to be written: Ilish, Atlantic salmon, European eel, Japanese eel, American shad, Beluga (sturgeon).

Further reading

GroupSharkRayCarpCatfishSalmonidHerringCodTunaPerch-likeCichlidReef fishEelFlatfishLivebearerAncientOther
UseFood fishFarmedAquarium fishSport fishingCulture and faithVenomous or dangerousInvasiveScience and research
OrderBest knownA to ZOldest firstNewest firstBy size
WorldGreat white shark A large, globally distributed predator known for its size and apex status in marine ecosystems.Shark · Coasts and shelves · 1758 🇮🇳 India and 4 moreRohu A large silver carp from South Asian rivers, farmed for food and prized as a game fish.Carp · Rivers and lakes 🇺🇸 United States and 4 moreSea lamprey A jawless, parasitic fish native to the Northern Hemisphere that attacks other fish.Ancient · Rivers and lakes · 1758 🇵🇭 Philippines and 4 moreMilkfish The sole living species of the family Chanidae, found across the Indo-Pacific.Other · Coasts and shelves 🇺🇸 United States and 3 moreSockeye salmon Anadromous Pacific salmon known for red spawning colour and zooplankton diet.Salmonid · Rivers and lakes · 1792 WorldViperfish Deep-sea fish with fang-like teeth and bioluminescent lures in the genus Chauliodus.Other · Open ocean · 1801 🇷🇺 RussiaSterlet A small Eurasian sturgeon found in rivers flowing to the Black, Azov, and Caspian seas.Ancient · Rivers and lakes · 1758 🇺🇸 United States and 1 moreLake sturgeon A large, long-lived freshwater fish native to North America.Ancient · Rivers and lakes 🇷🇺 Russia and 2 moreKaluga A massive semi-anadromous sturgeon from the Amur River basin hunted for caviar.Ancient · Rivers and lakes · 1872 🇺🇸 United StatesShovelnose sturgeon Smallest North American freshwater sturgeon, known for its shovel-shaped snout and caviar production.Ancient · Rivers and lakes · 1820 WorldLamprey Jawless fish with a sucking mouth found in temperate waters worldwide.Ancient · Rivers and lakes 🇧🇼 Botswana and 1 moreAfrican tigerfish Predatory freshwater fish known for sharp teeth and leaping hunting behaviour.Other · Rivers and lakes · 1861 🇺🇬 Uganda and 2 moreSilver cyprinid A small pelagic fish from Lake Victoria that supports regional food security.Other · Rivers and lakes 🇰🇪 Kenya and 4 moreRipon barbel A large freshwater cyprinid from East African lakes and rivers.Carp · Rivers and lakes · 1900 🇺🇸 United StatesGuadalupe bass A rare Texas endemic black bass prized by anglers for its fighting spirit.Other · Rivers and lakes 🇺🇸 United States and 1 moreSauger A freshwater perch species native to North American rivers.Perch-like · Rivers and lakes · 1834 🇧🇷 Brazil and 3 moreTambaqui A large freshwater fish from South America known for its heavy body and seed-eating habits.Other · Rivers and lakes 🇺🇸 United States and 1 moreMexican tetra A freshwater characin with surface and blind cave forms, studied for evolutionary biology.Other · Rivers and lakes 🇨🇦 Canada and 1 moreBigmouth buffalo A long-lived North American freshwater fish known for its terminal mouth and exceptional lifespan.Catfish · Rivers and lakes 🇺🇸 United StatesAmerican paddlefish Ancient freshwater fish with a sensory snout and filter-feeding habits.Ancient · Rivers and lakes · 1792 🇷🇺 RussiaComephorus Two species of pelagic sculpins endemic to Lake Baikal in Russia.Other · Rivers and lakes · 1800 🇧🇷 BrazilBanded leporinus A striped freshwater fish from the Amazon kept in home tanks and occasionally caught by anglers.Other · Rivers and lakes WorldSnakehead Elongated freshwater predators with air-breathing organs found in Asia and Africa.Other · Rivers and lakes 🇧🇷 Brazil and 1 moreArapaima Large freshwater fish from the Amazon basin known for its size and air-breathing ability.Ancient · Rivers and lakes Southeast AsiaGiant snakehead A large freshwater predator from Southeast Asia known for air breathing and invasive potential.Other · Rivers and lakes 🇹🇭 Thailand and 2 moreSiamese mud carp Freshwater cyprinid native to Mekong and Chao Phraya riversCarp · Rivers and lakes 🇧🇷 Brazil and 1 moreElectric eel Neotropical freshwater fish capable of generating powerful electric shocks for hunting and defence.Eel · Rivers and lakes · 1766 🇨🇳 ChinaChinese paddlefish A giant freshwater predator from China that is now extinct.Ancient · Rivers and lakes · 1862 🇺🇸 United States and 1 moreGreen sturgeon A large anadromous fish native to the northern Pacific Ocean.Shark · Coasts and shelves 🇺🇸 United States and 2 moreBluegill A common North American sunfish known for its blue gill covers and popularity with anglers.Perch-like · Rivers and lakes · 1854 WorldBasking shark The second-largest living fish, a slow-moving filter feeder found in temperate oceans worldwide.Shark · Coasts and shelves · 1765 🇷🇺 Russia and 3 moreBurbot A coldwater freshwater fish with a chin whisker, native to the Northern Hemisphere.Other · Rivers and lakes · 1758 🇨🇳 China and 3 moreAsian swamp eel A freshwater, air-breathing fish native to Asia and introduced elsewhere.Eel · Rivers and lakes 🇺🇸 United StatesWhite bass A silver-striped freshwater fish native to North American rivers and lakes.Other · Rivers and lakes 🇺🇸 United States and 1 moreAlewife A small North American herring that migrates between sea and rivers.Herring · Coasts and shelves

Photo credits on this page

The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.

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