DSHS says a two-year study found elevated levels of dioxins and polychlorinated biphenyl's, or PCBs, in catfish and spotted seatrout.
The advisory includes Chocolate Bay, East Bay, West Bay, Trinity Bay and contiguous waters.
The health agency says adults are advised to limit consumption of the two types of fish to no more than one 8-ounce meal per month.
Women who are nursing, pregnant or who may become pregnant and children should not eat catfish or spotted seatrout from Galveston Bay.
Spotted seatrout are also known as speckled trout.
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