North Texas Lake Recovering Since 2010 Golden Alga Fish Kill

A North Texas lake shows signs of recovery from a 2010 fish kill blamed on golden alga, the Texas Parks & Wildlife Department reported Wednesday.

Recent gill net surveys at Possum Kingdom reservoir found excellent examples of older, larger fish, the agency said.

Fish kills have been documented as far back as 2000 in what's commonly known as Possum Kingdom lake, about 60 miles west of Fort Worth.

Biologists in April 2010 estimated nearly 120,000 fish died in two golden alga-infested lakes. At least 50,000 fish were killed at Possum Kingdom, while nearly 69,000 fish were found dead about 90 miles southeast in Lake Whitney, TPWD officials had said.

Striped bass, which are stocked by the agency, have done especially well at Possum Kingdom, with good numbers of fish up to 30 inches long, TPWD fisheries biologist Robert Mauk said.

"Our surveys have not shown this many larger striped bass since the first fish kill in 2001, and there are also lots of 7-inch to 20-inch fish, which bodes well for the future," Mauk said.

White bass numbers were down from previous surveys, but Mauk says certain fish compete for the same food.

Blue catfish abundance was the highest documented for the reservoir, with fish that ranged from 11 inches to 35 inches.

The surveys involve placing 125-foot nets at 15 sites at the reservoir, leaving the nets overnight and then comparing sizes of the catch and overall numbers of fish hauled in to previous annual surveys, Mauk said. Results from the 2015 survey found more fish, of the 18-20 inches legal limit size, than in the past few years.

He did not have specific figures, but said in general that the number of fish this year was about 10 times what was found in a 2011 survey, also noting that TPWD officials try to stock the lake each year.

Golden alga is a naturally occurring event, typically in brackish waters, that can cause fish kills. There's no evidence that toxins, which can be produced by golden alga, are harmful to humans or other animals, according to the TPWD.

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