MIAMI (NewsNation) — There are thousands of dead fish in Miami’s Biscayne Bay and scientists are trying to figure out why.

The dead fish span about a ten mile area of the bay near Downtown Miami.

“We are beyond warning signs here. We are in an unprecedented emergency situation in Biscayne Bay,” Dr. Rachel Silverstein, with the Miami Waterkeeper organization, said.

Silvestein says several species of fish have come up dead and are suffocating because of a lack of oxygen in the water.

“Fish just like us need oxygen to survive. When there is too much pollution in the water and too much bacteria and algae, then the oxygen levels can drop really, really low when there are hot and still conditions like we have now in Biscayne Bay,” Silverstein said.

Silverstein blames fertilizer run off into the bay and sewage from Miami’s aging infrastructure.

Miami Mayor Francis Suarez posted on social media about the dead fish – saying he plans to tackle the city’s infrastructure problem.

“It has been several days and we are still seeing reports of fish and wildlife in distress. Unable to breathe, gathering in places they don’t normally gather, and gasping for air,” Silverstein said.

The Miami Waterkeeper is waiting on test results to explain exactly what is causing the problem.