08/20/2020
The fish kill reported in Port Aransas on Aug 17 was NOT caused by red tide.
On August 17 the Coastal Fisheries Kills and Spills Team was notified of a fish kill along the Gulf beach of Port Aransas. A site visit was conducted on the same day and dead fish were seen mostly in the tidal pools during low tide. No new fish were observed washing ashore.
The fish kill, dominated by Gulf menhaden, was observed extending from the South Jetty of Port Aransas to just south of Access Rd 1. The greatest densities of dead fish were observed between the South Jetty and Avenue G.
Water samples collected along the beach by TPWD and UTMSI ruled out Red Tide (Karenia brevis) and confirmed a diatom bloom.
A low dissolved oxygen (DO) event in the early morning was identified as the cause of the fish kill. The uptake of oxygen by the bloom, Gulf Menhaden feeding on the bloom, and with low winds to prevent water mixing, created hypoxic conditions that caused the fish kill.