Long-Term Monitoring at East and West Flower Garden Banks: 2020 and 2021 Annual Report

This report summarizes benthic community observations and water quality data collected from East Flower Garden Bank (EFGB) and West Flower Garden Bank (WFGB) coral reefs in 2020 and 2021, as part of a program that has generated nearly 32 years of monitoring data. EFGB and WFGB are part of Flower Garden Banks National Marine Sanctuary (FGBNMS), located in the northwestern Gulf of Mexico. The annual long-term monitoring program began in 1989 and is funded by FGBNMS and the Bureau of Ocean Energy Management, with support from the National Marine Sanctuary Foundation. Limited fieldwork and data collection were completed in 2020 and 2021 due to vessel, diving, and other operational restrictions established in response to the COVID-19 pandemic. In 2020, a single quarterly water sampling cruise was completed, followed by a cruise to exchange water quality instruments. In 2021, two water sampling cruises were completed and instruments were exchanged. A subset of repetitive photostations at EFGB (n = 33) and WFGB (n = 34) were captured within one-hectare study sites, representing 89% and 83% of all photostations at EFGB and WFGB, respectively. In 2021, mean coral cover was 67% within EFGB repetitive photostations and 68% within WFGB repetitive photostations. Bleaching and/or paling was observed in repetitive photostations at both banks. There were no signs of stony coral tissue loss disease within either of the one- hectare study sites. Seawater temperatures on the reef exceeded 30 oC temporarily at both banks in 2020 and 2021, though coral bleaching was only observed in 2021. A significant monotonic increasing trend in seawater temperature was detected at both banks from 1990 to 2021, indicating ocean temperatures have risen at FGBNMS over the past three decades. The results of this report extend one of the longest records of coral reef condition in the Gulf of Mexico and Caribbean region.

Key Words

benthic community, coral ecosystem, coral reef, fish community, long-term monitoring, Flower Garden Banks National Marine Sanctuary, Gulf of Mexico, marine protected area, water quality