Between sea and river
Fish that migrate between salt and fresh water to breed, like salmon and hilsa. 37 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
Still to be written: Ilish, Atlantic salmon, European eel, Japanese eel, American shad, Beluga (sturgeon).
Further reading
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 3 moreSockeye salmon
Anadromous Pacific salmon known for red spawning colour and zooplankton diet.Salmonid · Rivers and lakes · 1792
🇺🇸 United States and 1 moreLake sturgeon
A large, long-lived freshwater fish native to North America.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
🇰🇪 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
🇨🇦 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
🇧🇷 BrazilBanded leporinus
A striped freshwater fish from the Amazon kept in home tanks and occasionally caught by anglers.Other · Rivers and lakes
🇺🇸 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
🇷🇺 Russia and 3 moreBurbot
A coldwater freshwater fish with a chin whisker, native to the Northern Hemisphere.Other · Rivers and lakes · 1758
🇺🇸 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.
- Great white shark: Sharkdiver.com, Public domain, source
- Sea lamprey: Fernando Losada Rodríguez, CC BY-SA 4.0, source
- Rohu: Wiki Farazi, CC0, source
- Sockeye salmon: Timothy Knepp of the Fish and Wildlife Service., Public domain, source
- Lake sturgeon: USFWS Mountain-Prairie, Public domain, source
- African tigerfish: Totti, CC BY-SA 4.0, source
- Ripon barbel: Georges Albert Boulenger, Public domain, source
- Guadalupe bass: Nick Loveland, CC0, source
- Sauger: Duane Raver, Public domain, source
- Bigmouth buffalo: Unknown author, Public domain, source
- American paddlefish: Timothy Knepp, Public domain, source
- Banded leporinus: Ltshears, Public domain, source
- Green sturgeon: Muséum d'histoire Naturelle, Public domain, source
- Bluegill: Fredlyfish4, CC BY-SA 3.0, source
- Burbot: Unknown author, CC BY-SA 3.0, source
- White bass: Nick Loveland, CC0, source
- Alewife: Unknown author, CC BY-SA 3.0, source