Story Research

The Salton Sea: Fishing for Answers

Elizabeth Chapin



Southern California’s Salton Sea is an ecological disaster zone—it’s a stinking, stagnant, salty lake that experiences frequent “die-offs” of thousands of fish and birds. It appears nearly devoid of life, but the oddly beautiful body of water is a surprising oasis—it continues to support a valuable ecosystem of fish and migrating birds. A Sacramento State study aims to see how long this life can last.

The Salton Sea was created by accident. In 1905, the Colorado River flooded and broke the canals leading into the developing Imperial Valley. Until 1907, the river’s entire volume rushed to the lowest point in the valley. By the time engineers were able to stop the water flow, they had created California’s largest body of water and one of the world’s largest inland seas.

The misadventure continued. In the 1950s, resort cities popped up along the Salton’s shores in an effort to attract tourists and their money. The success was short-lived and the destination spot turned into a sorry scene. Since the sea doesn’t have an outlet to flush out built-up salts, and is fed by dirty agricultural runoff instead of fresh water, the salinity levels increased at an incredibly high rate. The water was too salty for tourists to tolerate and wildlife to withstand. Most of the animals died and the people fled, abandoning their homes and businesses.

A half-century later, a few species of fish have been hearty enough to survive. One of them is the tilapia and it’s key to the survival of the Salton’s ecosystem, which includes millions of birds that depend on them for food.

Sacramento State biology professor Ron Coleman and student Shannon Waters are trying to find out how long the ecosystem will be able to be sustained by the tilapia fish as the salinity levels continue to increase. Waters says the Salton Sea isn’t getting any less salty, and that’s not great news.

“The salinity level of the Salton Sea is about 45 parts per thousand (ppt), which is about 30 percent saltier than the ocean,” Waters said. “It’s projected to rise to around 60 ppt in the coming years.”

Waters says she plans on slowly increasing the salinity level in the tanks of captive tilapia to replicate this expected rise. With help from California Fish and Game and the USGS, Coleman and Waters collected the fish from the Salton Sea last May. The tilapias have been spawning in a lab at Sacramento State.

Dr. Coleman says that the Salton Sea’s tilapias have morphed into a hybrid breed: a combination of several different types of tilapia that have been introduced to the sea over the years.

“Only the fish with the strongest salinity resistance traits survived—and evolved into this unique hybrid rather quickly.” Coleman said.

But can the Salton super-fish evolve rapidly enough as the sea’s water reaches lethal levels of salinity?

“We expect their reproduction to taper off as the water gets saltier,” Coleman said. “The fish will become too stressed to reproduce or take care of their young.”

That would be bad news for the Salton and the millions of migratory birds that depend on its resources. The spot has become one of the most important migratory bird habitats in the U.S.—mainly because there’s no place else to go.

“The birds migrate up and down California’s coast on what is called the Pacific flyway. Since the state’s wetlands are disappearing, they are utilizing other areas like the Salton Sea,” Coleman said. “If this fish doesn’t survive, the impact could change the entire Pacific coast.”

The research could potentially make a big impact in the scientific community, too. Protecting and preserving the Salton Sea has been a controversial topic among scientists because it is not a naturally-occurring body of water. But Waters says that the number of wildlife that now depend on it illustrate its worth.

“The project raises the awareness of the Salton Sea’s importance,” Waters said. “Even though it was a man-made mistake, it has now become an important habitat and it needs to be preserved.”


Dead fish: a familiar sight on the Salton’s shore.

Migratory birds line the shore. They now depend on this habitat as many natural wetlands have disappeared.

Waters catching the tilapia fish with a cast net.

Sacramento State student Shannon Waters and professor Ron Coleman present the project at the CSU COAST/WRPI poster presentation in January.