What lives in the Great Salt Lake?

The Great Salt Lake in northern Utah is one of the most unique and biologically fascinating ecosystems in North America. Despite its extremely high salinity—often 5 to 10 times saltier than the ocean—the lake supports a surprisingly rich and specialized web of life. While few species can survive directly in its salty waters, the lake’s ecosystem thrives with extremophiles, brine-loving organisms, and millions of birds that depend on its surrounding wetlands and microbial food chain.

1. Brine Shrimp (Artemia franciscana)

The most iconic and ecologically important inhabitant of the Great Salt Lake is the brine shrimp. These tiny, translucent crustaceans are perfectly adapted to the lake’s hypersaline conditions and play a central role in its food web.

Lifecycle: Brine shrimp hatch from cysts, which are highly resilient and can survive years of dormancy in dry conditions.

Diet: They feed on algae and bacteria in the lake.

Ecological Role: Brine shrimp are a crucial food source for millions of migratory birds. Their abundance also supports a lucrative brine shrimp harvesting industry.

Economic Value: The brine shrimp industry in the lake is valued at tens of millions of dollars annually, primarily for aquaculture and aquarium feed.

2. Brine Flies (Ephydra spp.)

Equally adapted to the salty environment, brine flies are another vital species in the Great Salt Lake ecosystem.

Appearance: Small, dark-bodied flies that swarm in large numbers near the shoreline.

Lifecycle: Their larvae live underwater, feeding on organic material, while adults live only a few days.

Unique Adaptation: Brine fly larvae can survive in extreme salinity and low-oxygen environments. They even build underwater cocoons to pupate.

Bird Food: Like brine shrimp, brine flies are a critical food source for birds, especially in spring and summer.

3. Algae and Halophilic Microorganisms

Beneath the surface of the lake, vast colonies of halophilic (salt-loving) microorganisms flourish. These include:

Dunaliella salina: A green microalga that thrives in hypersaline water and produces carotenoids (like beta-carotene), giving parts of the lake a reddish or pink hue.

Halobacteria: Salt-loving archaea that add to the lake’s coloration and help decompose organic matter.

These microscopic organisms are the foundation of the lake’s microbial loop, sustaining brine shrimp and flies and indirectly supporting bird populations.

4. Birds: The Sky-Borne Residents

The Great Salt Lake and its extensive wetlands serve as one of the most important stopovers for migratory birds in North America. The region is part of the Pacific Flyway, and over 10 million birds representing 250 species may visit the lake annually.

Some notable species include:

1. Eared Grebes: More than 1 million may stage here during migration, feeding almost exclusively on brine shrimp.
2. American Avocets and Black-necked Stilts: Common waders feeding along mudflats.
3. Wilson’s Phalaropes: Over 500,000 may gather here in late summer, gorging on brine shrimp to double their body weight before migrating to South America.
4. Snowy Plovers: A rare shorebird that breeds on the lake’s alkaline flats.
5. California Gulls: The state bird of Utah, these gulls nest on lake islands and feed on brine flies.

The Bear River Migratory Bird Refuge, on the northeastern arm of the lake, is a globally significant wetland and breeding ground for these birds.

5. Wetland and Shoreline Life

While the hypersaline waters of the lake proper support few species beyond shrimp and flies, the surrounding freshwater and brackish wetlands host diverse plant and animal life:

Plants: Bulrush, sedges, saltgrass, and cattails dominate the wetlands.

Mammals: Muskrats, beavers, raccoons, and occasionally mule deer inhabit marshy areas.

Amphibians and Insects: Frogs, dragonflies, and mosquitoes are common in the wetlands.

These habitats are essential for nesting, rearing young, and foraging.

6. Fish? Not in the Lake

Due to its extreme salinity, the open waters of the Great Salt Lake do not support fish. However, in the river mouths and freshwater wetlands that fringe the lake, several fish species do occur, including:

• Carp
• Catfish
• White bass
• Trout (in tributaries)

Fish are typically confined to Bear River Bay and Farmington Bay, where the salinity is diluted by freshwater inflows.

Conclusion

Although it might appear barren at first glance, the Great Salt Lake is teeming with life, just of a different kind than in freshwater lakes or alpine forests. Its extremophile ecosystem is built around simple but abundant organisms like brine shrimp, brine flies, and halophilic microbes, which in turn support a dazzling array of migratory birds and wetland wildlife. This delicate food web is uniquely adapted to the lake’s hypersaline conditions, but also highly sensitive to water level changes and salinity shifts. Protecting the lake’s inflows and surrounding habitats is essential not just for ecological health but for global biodiversity.