One of the most unique and important habitats in Utah is the Great Salt Lake. It’s the largest U.S. lake west of the Mississippi River and it’s the 4th largest terminal lake (meaning it has no outlet) in the world. The waters of the Great Salt Lake are typically 3 to 5 times saltier than the ocean . For that reason, you won’t find any fish; in fact, the largest aquatic animals are brine shrimp which are little crustaceans that are found worldwide in saline lakes and seas. You may know the brine shrimp as “sea monkeys” as they are called when packaged and sold as novelty gifts.
Brine shrimp like their water to be between 2 and 25 percent salt. The Great Salt Lake species is especially well adapted to cold . If the temperature is moderate and there is plenty of algae to eat, the females will produce more live young. As temperatures lower, food supply decreases, or other stress factors appear, females will switch to producing cysts which are tiny hard-shelled egg-like spheres. Cysts are metabolically inactive, and can survive without food, without oxygen, even at below freezing temperatures. During winter, the adult brine shrimp typically die from lack of food or low temperature, but the cysts are able to survive the winter and form a large population base for the next generation of brine shrimp.
Brine shrimp practically fill the Great Salt Lake. At times, they become so numerous that you can see them as large reddish-brown streaks on the surface of the lake. Because birds like to eat them, the Great Salt Lake supports one of the largest migratory bird concentrations in Western North America. Birds like the Eared Grebe and Wilson’s Phalarope reach their largest concentrations anywhere as they load up at one of the world’s largest shrimp buffets. In all, during peak migration you’ll find 2 to 5 million birds using the Great Salt Lake to obtain the nourishment required for their long and strenuous trip. It’s fascinating that these tiny prehistoric crustaceans play such an important role in sustaining the large number and wide variety of birds that travel through or live in our State.
Audio: Sound for this recording was generously provided by the Western Soundscape Archive at the University of Utah J. Willard Marriott Library. https://westernsoundscape.org/
Photo: Courtesy USGS, https://ut.water.usgs.gov/greatsaltlake/shrimp/
Text: Stokes Nature Center: Anna Paul, Holly Strand logannature.org
Sources & Additional Reading
USGS, Utah Water Science Center, Brine Shrimp and Ecology of Great Salt Lake. (Courtesy Internet Archive Wayback Machine, Apr 15, 2008) https://wildaboututah.org/wp-content/uploads/080415-Wayback-USGS-Brine-Shrimp-and-Ecology-of-Great-Salt-Lake.pdf Formerly: https://ut.water.usgs.gov/greatsaltlake/shrimp/
US Fish and Wildlife Service, Bear River Migratory Refuge. https://www.fws.gov/bearriver/
Westminster College GSL Project –
Great Salt Lake, Utah, USGS, https://pubs.usgs.gov/wri/wri994189/PDF/WRI99-4189.pdf
Great Salt Lake Ecosystem Program, Utah Division of Wildlife Resources, State of Utah, https://wildlife.utah.gov/gsl/
Larese-Casanova, Mark, The Brine Shrimp of Great Salt Lake, Wild About Utah, Jan 6, 2011, https://wildaboututah.org/the-brine-shrimp-of-great-salt-lake/
Brine Shrimp, Genetic Science Learning Center, University of Utah, https://learn.genetics.utah.edu/content/gsl/foodweb/brine_shrimp/
Salt Lake Brine Shrimp, https://saltlakebrineshrimp.com/harvest/
Brine shrimp officially named Utah’s state crustacean, March 20, 2023, Utah Division of Wildlife Resources, Utah Department of Natural Resources, State of Utah, https://wildlife.utah.gov/news/utah-wildlife-news/1608-brine-shrimp-officially-named-state-crustacean.html