Elevated salinities and water temperatures are believed to be responsible for the extraordinarily high concentrations of bryozoans, Zoobotryon verticillatum. The dense, filamentous bryozoan fills shrimp nets and becomes lodged in the TEDs after relatively short periods of towing, rendering the TEDs ineffective in expelling sea turtles from the shrimp nets as well as negatively impacting fishermen's catches. According to local shrimpers, they were able to relocate to bryozoan-free areas initially, but, as the bryozoan concentration has spread, they are unable to find clear areas to trawl throughout virtually all of the bay. TPWD's investigation has confirmed the widespread nature of the problem. Under the current conditions, tows longer than 20-30 minutes cannot be made because of the large catches of bryozoans.
Shrimpers report that shrimp can be found interspersed within the bryozoan mats.
TEDs become quickly blocked with the organisms, making them non-functional for turtle escape and sometimes requiring shrimpers to empty the net from the mouth rather than the tail bag. This process is much slower and a sea turtle that might be incidentally caught with the bryozoan mats would be submerged for a longer period of time than if the net can be emptied from the tail bag. The AA finds that the impacts of the current drought conditions in eastern Texas on Galveston Bay have created special environmental conditions that may make trawling with TED-equipped nets impracticable. Therefore, the AA issues this notification to authorize the use of restricted tow times as an alternative to the use of TEDs in inshore waters of Galveston Bay. TPWD is continuing to monitor the situation and will cooperate with NMFS in determining the ongoing extent of the bryozoan occurrence in Galveston Bay.