The Great Salt Lake in Utah often prompts questions about its aquatic life. While known for its extreme saltiness, the main body of the lake largely does not support fish. However, fish can be found in specific areas.
The Lake’s Extreme Conditions
The Great Salt Lake is a terminal lake, with water leaving primarily through evaporation. This process concentrates dissolved minerals and salts, making the lake significantly saltier than the ocean.
The lake’s main southern basin, Gilbert Bay, can vary widely from 5% to 27% salinity, two to seven times saltier than the ocean. The northern arm, isolated by a railroad causeway, can reach even higher salinities, sometimes exceeding 30%. Such hypersaline conditions are inhospitable to most fish species. Fish require a specific osmotic balance to survive, and the Great Salt Lake’s water can draw water out of their bodies, leading to dehydration and death. Fluctuations in water levels further impact the lake’s salinity, creating an unstable environment.
Life Adapted to Salinity
Despite the challenging environment, the Great Salt Lake teems with life adapted to its high salinity. Brine shrimp are prominent inhabitants, thriving in salinities from 3% to 33%. These small crustaceans consume algae and are a food source for millions of migratory birds. Brine shrimp also produce resilient, dormant cysts that survive harsh conditions, aiding their species’ persistence.
The lake’s distinctive colors, ranging from green to pink, are due to various types of algae and salt-loving microorganisms. For instance, Dunaliella viridis algae give the southern arm a green hue, while Dunaliella salina and certain bacteria contribute to the pinkish-orange and violet colors often seen in the more saline northern arm. Brine flies also flourish, providing another important food source for diverse bird populations visiting the lake.
Fish in Tributaries and Unique Areas
While the open waters of the Great Salt Lake are largely devoid of fish due to their high salt content, fish populations exist in specific, less saline areas. Freshwater tributaries like the Bear, Weber, and Jordan rivers flow into the lake, creating localized zones of lower salinity. In these fresher bays, such as Bear River Bay and Farmington Bay, fish species like carp, Utah chub, and various minnows can be found, especially during high spring runoff.
Native species like Bonneville cutthroat trout are found in these freshwater tributaries. If these fish venture into the main, saltier lake, they cannot survive.
Human-engineered structures, such as the railroad causeway, have also created distinct hydrological sections within the lake that maintain lower salinity. Specific impoundments and spring-fed ponds adjacent to the lake, like Locomotive Springs, can sustain fish populations year-round, sometimes stocked with rainbow trout and least chub.