Fish and pelicans found dead in and around Riviera Bay Lake and Coffee Pot Bayou in St. Petersburg early this year was the result of a combination of factors, according to St. Petersburg officials.
Water tests indicated the fish kill was caused by the introduction of nutrients into the lake, cold weather and a powerful neurotoxin. The pelicans then ate the dead and debilitated fish.
The study was conducted by an independent team of biologists who work for a company called Arcadis, a city of St. Petersburg statement said.
The Arcadis scientists took water samples from Coffee Pot Bayou and Riviera Bay Lake No. 1, a mostly freshwater retention pond.
The findings were based on "weeks of exhaustive sampling and intense testing," the statement said.
"Our commitment to getting to the bottom of this unfortunate fish and bird kill included the hiring an independent third party team to fully analyze the water quality in the region," said St. Petersburg's Interim Director of Water Resources John Palenchar.
"This should alleviate all fears that this natural occurrence had anything to do with the discharge of partially treated wastewater over the past two summers."
The city of St. Petersburg will continue to work with Arcadis on ways to help increase the water quality on both basins, the statement added.