The “fish kill” was a result of low dissolved oxygen in the water, which is common in the summer when temperatures rise, according to Texas Parks & Wildlife.
Officials are asking beachgoers to steer clear of a Texas beach after thousands of dead fish began washing up on Friday.
The “fish kill” on the Gulf Coast beach, about 65 miles south of Houston, was a result of low dissolved oxygen in the water, according to Texas Parks & Wildlife. Low oxygen levels are common in the summer when temperatures rise, making it so the fish can’t ‘breathe’ under water, the department said.
The fish washed up “by the thousands” and were mostly Gulf menhaden, which are often used for bait. A video of the event showed thousands of fish carcasses on the surface of the water at Bryan Beach.
Officials with the Quintana Beach County Park urged swimmers to avoid the coast, citing high bacterial levels and the sharp fins of the dead fish.
“Our recommendation is that you avoid the beach altogether until this event is over,” the officials said in a Facebook post. “We definitely advise that no one enters the water.”
Clean up efforts started on Friday and wrapped up on Sunday when the last of the remains — “deteriorated to the point of being shredded skeletons” — had washed onto the Texas shore, officials said.
Even after the clean up, local officials suggested visitors wait a couple of days before heading to the beach.
Water samples taken from the Gulf Intracoastal Canal and the Brazos River, which feed into the coast, were found to have almost no dissolved oxygen in them, local officials said.
The Texas Parks & Wildlife Kills and Spills Team said low dissolved oxygen in water is “a natural occurrence” resulting from photosynthesis and aerobic respiration.
“Increased dissolved oxygen during the day is a result of photosynthesis which is driven by sunlight. Photosynthesis stops at night and may slow down on cloudy days, but plants and animals in the water continue to respire and consume free oxygen, decreasing the dissolved oxygen concentration,” the department said in a statement.
“Often before a kill event occurs, fish can be seen trying to get oxygen by gulping at the surface of the water early in the morning,” they added.
Quintana Beach County Park officials said there was no evidence of a chemical spill having caused the mass fish kill event.