Whatever is behind this week's lessening of red tide concentrations along the upper Texas coast, resource managers and anglers will take it. It's been a lot less in evidence this week. Water samples taken midweek along the Galveston Island beachfront showed little of the dinoflagelate algae Gymnodinium breve that causes red tide. Also, evidence of fish kills has decreased this week.
Red tide is caused by toxins produced by the algae.
The breve cells are fairly common in marine water but become a problem only when the algae numbers are higher than normal. When concentrations of the algae reach 100 to 200 cells in a liter of water, they produce enough toxin to kill fish. The poison is a neurotoxin that paralyzes the respiratory systems of fish and other sea life. But scientists believe high salinity levels, calm conditions and high water temperature are triggers. And Texas' upper coast has seen its share of all those this summer.