Skip to content

SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It Again OceanEye to eye with Britain's hidden sharks at SharkAdemy - Oceanographic RiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at all OceanShedd Aquarium Sends Shark Eggs to Bolster Wild Populations SpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for Conservation OceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray Area SpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow Reductions FisheriesAdams River Salmon Run in Thompson-Nicola IndiaHilsa production dropped 26% in five years, fisheries minister tells parliament SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It Again OceanEye to eye with Britain's hidden sharks at SharkAdemy - Oceanographic RiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at all OceanShedd Aquarium Sends Shark Eggs to Bolster Wild Populations SpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for Conservation OceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray Area SpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow Reductions FisheriesAdams River Salmon Run in Thompson-Nicola IndiaHilsa production dropped 26% in five years, fisheries minister tells parliament

EveryFish

Estuaries and mangroves

Where rivers meet the sea: estuaries, backwaters and mangroves. 53 fish on EveryFish so far.

Brackish water is the mix of fresh and salt water found in estuaries, lagoons, backwaters and mangrove creeks, where rivers meet the sea. Its saltiness rises and falls with the tides and the seasons, so only fish that can cope with change live there all the time. These waters are rich in food from the land and the sea, and they act as nurseries for many fish that later live on coasts and reefs.

Fish that handle change

Brackish-water fish are euryhaline: they can adjust the salt balance of their bodies as the water changes. Mullets, milkfish, scats, barramundi and the pearlspot live in India's backwaters and lagoons, such as Vembanad in Kerala and Chilika in Odisha. Mudskippers climb out onto mangrove roots at low tide, breathing through their wet skin. Archerfish shoot down insects from overhanging leaves. Bull sharks swim from the sea into estuaries and far up rivers.

Farms and pressures

Coastal ponds that take in tidal water are used to farm fish and shrimp: the bheris of West Bengal, the pokkali fields of Kerala and the milkfish ponds of the Philippines and Indonesia. Estuaries are also where ports, cities and industries crowd, and many are polluted or reclaimed. Clearing mangroves for shrimp farms has removed nurseries for wild fish across tropical Asia, and dams upstream cut the fresh water that keeps estuaries brackish.

Famous estuaries and mangroves fish

MilkfishFarmed in brackish ponds across Asia

Banded archerfishShoots insects from mangrove leaves

Still to be written: Barramundi, Green chromide, Giant mudskipper, Scatophagus argus, Flathead grey mullet, Bull shark.

Further reading

Photo credits on this page

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

Milkfish: Wiki Farazi, CC0, source
Caspian roach: Brücke-Osteuropa, Public domain, source
Banded archerfish: Chrumps, CC BY-SA 3.0, source

The weekly digest

Every Monday: the fish of the day, new pages on EveryFish, and the conferences and anniversaries of the week ahead.