The Great Salt Lake in Utah is often thought to be devoid of fish due to its extreme saltiness. However, this unique endorheic, or closed basin, lake does support certain fish species. These fish primarily inhabit areas where freshwater inflows dilute the intense salinity. This article explores the fish found in and around the lake and their ecological roles.
The Great Salt Lake’s Fish Species
The main body of the Great Salt Lake is too saline for most fish, with salinity levels ranging from 5% to 27% (compared to the ocean’s approximately 3.5%). However, certain fish species inhabit its less concentrated fringes, including Farmington Bay, Bear River Bay, and river deltas. The most commonly cited fish found near the lake’s influence are the Bonneville cutthroat trout, common carp, and least chub. Rainbow trout are also regularly stocked in springs directly connected to the lake.
Brine shrimp (Artemia franciscana) are the most abundant and well-known inhabitants of the Great Salt Lake’s highly saline waters. These tiny crustaceans are the sole permanent residents of the lake’s open waters, forming the base of the food web. Fish species typically remain in the fresher waters of inflowing rivers and their deltas, venturing into slightly saltier bays only when conditions permit.
How Fish Survive High Salinity
Fish survival in and around the Great Salt Lake largely depends on their ability to tolerate or avoid extreme salinity. Most fish are found in the less saline areas, such as the freshwater marshes, springs, and river deltas that flow into the lake. The South Arm, for instance, receives most of the freshwater inflows and maintains a lower average salinity of about 11% to 12%, making it more hospitable than the North Arm, which can reach 25% to 30% salinity. This gradient allows fish to persist in these diluted zones.
Certain species, like common carp and least chub, exhibit a higher tolerance for brackish conditions and can move further into the slightly saltier waters of the bays. These fish possess physiological mechanisms, such as osmoregulation, which allow them to manage the balance of salt and water within their bodies. This adaptation helps them cope with the osmotic stress of a high-salt environment. However, sustained exposure to the lake’s most concentrated areas remains lethal for fish.
Fish Role in the Ecosystem and Current Issues
Fish in the less saline areas play a role in the broader Great Salt Lake ecosystem, serving as a food source for some predatory birds and other wildlife. However, the most significant ecological contribution to the lake’s avian populations comes from brine shrimp and brine flies. Millions of migratory birds, including Wilson’s phalaropes and American avocets, depend heavily on these invertebrate populations as a food source.
The Great Salt Lake and its aquatic life face significant environmental challenges due to declining water levels and increasing salinity. Decades of drought and water diversion from inflowing rivers have led to a reduction in water volume. This increases the lake’s overall salinity, threatening the ecosystem’s balance.
If salinity continues to rise, it could severely impact brine shrimp populations, jeopardizing the birds that rely on them. Conservation efforts are crucial to maintaining the lake’s water levels and preserving its fish populations and the broader ecosystem.