Thousands of dead fish arrive in the Gulf of Texas – 06/15/2023 – Environment

Thousands of dead fish have washed ashore on the Texas Gulf Coast since Friday, after running out of oxygen due to high water temperatures, officials said.

Brazoria County park officials said a cleanup effort is underway, but more fish are expected to arrive on shore. Photos published by Parque Municipal Quintana Beach, on Saturday (10), show dead fish floating in coastal waters.

The cause was a “perfect” conjunction of bad conditions, according to Bryan Frazier, director of the Brazoria County Parks Department.

“Warm water holds much less oxygen than cold water. The calm sea and cloudy sky in the area prevented oxygen from being infused into the ocean water. The waves would add oxygen to the water and the cloudy sky reduced the ability of microscopic organisms to produce oxygen through photosynthesis”, explains Frazier.

When schools of fish are trapped in shallow, warm water, they can begin to act erratically from lack of oxygen, which further depletes the oxygen in the water.

Katie St. Clair, manager of marine life at A&M University in Galveston, Texas, said warming Gulf Coast waters due to climate change may have contributed to the fish kills.

“As we have an increase in water temperature, certainly that could cause more events like this to happen,” said St. Clair, “especially in our shallow, nearshore or coastal environments.”

The National Weather Service recorded a maximum temperature of 33.3°C in Brazoria County on Friday, when dead fish were reported for the first time on the beach.

Frazier added that such occurrences “are not very rare” in this region and begin when the water warms up during the summer.

“It’s a little alarming to see a wave of dead fish wash up on the beach,” Frazier said. But he added that local sea conditions would improve as waves add oxygen back to the water and fish swim away from low-oxygen areas.

“‘Mother Nature’ has a way of balancing that,” Frazier said. “It should correct itself here in the very near future.”

A UN report concluded in 2019 that warming ocean water has increased the incidence of hypoxia —low oxygen levels—in coastal waters, threatening fish populations. One of the report’s authors said at the time that oxygen loss and other effects of global warming “would create enormous pressure” on the Gulf Coast region in the future.

In addition to localized cases of hypoxia, a large “dead zone” of water, covering thousands of square kilometers, is known to form in the Gulf of Mexico during the summer months.

The US National Oceanic and Atmospheric Administration predicted Monday that this dead zone would be smaller than normal this year, covering nearly 7,000 square miles of coastal waters.

St. Clair said the fish kills could have a significant environmental impact because dead fish – particularly sardines and herring – play a “critical role” in the Gulf’s ecosystem.

“You could see cascading impacts if we continue to have these large fish kills,” she said.

The fish began washing up on the beach in Brazoria County, about 104 km south of Houston, on Friday morning, Frazier said, and park crews were quickly dispatched to pull them out and bury them beforehand. let them begin to rot in the midday heat.

“We need to remove them quickly,” Frazier said. “It doesn’t take long for them to produce a bad smell in over 30 degree heat.”

Translated by Luiz Roberto M. Gonçalves