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Davis Journal

GSL causeway improvements already paying dividends

Feb 22, 2024 11:44AM ● By Braden Nelsen
Some minor improvements at the Great Salt Lake have made major changes already this year. Photo courtesy of Utah DWR

Some minor improvements at the Great Salt Lake have made major changes already this year. Photo courtesy of Utah DWR

GREAT SALT LAKE —Davis County locals are well aware of just how important brine shrimp are to the local ecosystem. Even though they are microscopic, these little crustaceans provide food for many birds, both permanent and migratory, as well as a large part of the economy. Their numbers have been hurting in recent years, but, thanks to some small improvements, big changes are already being seen.

The Utah Division of Wildlife Resources (DWR) manages the species and knows better than many just how vital they are to the region. Despite a good water year in 2023, and a promising water year in 2024, drought conditions, especially for the Great Salt Lake still exist. These conditions, along with a breach in the causeway caused a spike in salinity which had a surprisingly devastating effect on the lake locals. 

The 2022-2023 harvest of brine shrimp eggs, or cysts, yielded 6 million pounds less than usual. Fortunately, action was taken, the breach in the berm was taken care of, and numbers are quickly returning to normal. The latest numbers from the DWR put brine shrimp cysts at 29 million pounds. 

“We thank our sister agencies and other partners for taking quick action to address salinity issues,” Great Salt Lake Ecosystem Program Manager John Luft said. “It allowed the brine shrimp to quickly rebound, and hatch rates were around 90% this year, as opposed to 60% last year when the salinity levels were higher. The greater-than-90% hatch rates are what give the Great Salt Lake brine shrimp cysts their reputation for being some of the highest quality cysts in the world.”

It’s vital that the levels of these animals remain sustainable for many reasons, both economical and ecological.

“It’s a tricky balance because the adult shrimp typically freeze and die each December, while the cysts will survive and hatch in March,” Luft said. “When the cysts hatch, they survive by eating the algae in the lake, which is also what the juvenile and adult brine shrimp eat. However, if there are too many cysts that hatch, they eat all the algae and run out of food before they reach adulthood, which is when they produce more cysts. So we have to manage the harvest to fit that balance, which is about 21-27 cysts per liter of water. Once it reaches that threshold, we either close the harvest for the year or we extend it if enough cysts haven’t been harvested. You can over harvest them, but you can also under harvest them, which is why it’s a delicate balance that requires a lot of monitoring.”

The Great Salt Lake and the shrimp therein provide a vital ecosystem for 10 million migratory birds, spanning 330 different species, including millions of eared grebes. This particular bird molts while here which makes them flightless, and completely dependent on the nutrition that the brine shrimp provide. A disappearance in the shrimp or their environment would spell disaster for the grebes and millions of other birds, having a ripple effect across the globe.