Tens of thousands of dead fish washed up on Texas beaches last week, and officials say the fish kill was caused by low oxygen levels.
The fish, mostly menhaden, began washing up on Bryan Beach, near the mouth of the Brazos River, on Friday.
A video and photos shared by Quintana Beach County Park in Brazoria County, about six miles up the coast from Bryan Beach show thousands of rotting fish on the Gulf Coast beach Friday.
Park officials said the fish kill was caused by low dissolved oxygen in the water due to a combination of warm water, calm seas and cloudy skies. Cool water holds more oxygen than warm water, officials said, and when water temperatures rise above 70 degrees Fahrenheit, the menhaden can experience hypoxia.
“This causes fish to act more erratically, which in turn, further depletes the oxygen from the water. Low oxygen can cause menhaden to die in this manner,” park officials said.
Calm seas for the last three weeks have reduced surface mixing, another way oxygen enters the water, and cloudy skies have reduced oxygen-producing photosynthesis among microscopic organisms such as phytoplankton.
“In nutshell, it was the perfect storm to deplete the oxygen levels inshore,” park officials said.
Dead fish continued washing ashore over the weekend, even as the removal process got underway. The last of the fish to wash in on Sunday were “deteriorated to the point of being shredded skeletons,” park officials said.
Park officials used heavy machinery to remove most of the dead fish, and any fish that remain will be buried by high tides over the coming days, officials said.
