March 12, 2026
This report summarizes fish and benthic community observations and water quality data collected from East Flower Garden Bank (EFGB) and West Flower Garden Bank (WFGB) in 2024, along with 35 years of historical monitoring data.
In 2024, mean coral cover was 56%, estimated from random transect data within EFGB and WFGB one-hectare study sites. Coral cover at WFGB has increased significantly over time, while EFGB values have remained stable. The Orbicella spp. complex, listed as threatened under the Endangered Species Act, accounted for the majority of the coral cover within the study sites.
Benthic composition across the coral reef differed significantly between the banks, largely due to differences in macroalgae and colonizable substrate cover. While mean macroalgae cover was 24% within the EFGB study site and 17% within the WFGB study site, macroalgae cover has increased significantly at both banks since 1998.
The reef fish community was dominated in terms of relative abundance by the families Labridae (wrasses) and Pomacentridae (damselfishes). Biomass was evenly distributed between large and small individuals, and herbivores represented the greatest mean biomass at both banks, marking a notable shift from previous years when piscivores dominated total biomass. No non-native regal demoiselles were observed in 2024; however, they were observed on nearby artificial reef sites and Stetson Bank.
A significant increase in reef-cap seawater temperature was detected at both banks from 1990 to 2024. In situ reef-depth temperature data indicated that EFGB approached, while WFGB exceeded, site-specific bleaching thresholds in 2024. Coral paling was first observed in July, with bleaching more pronounced later in the season. The 2024 bleaching event followed a major bleaching event in 2023 and is the first instance of consecutive bleaching years recorded at Flower Garden Banks National Marine Sanctuary.
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The Conservation Series is a NOAA technical publication series hosted by the Office of National Marine Sanctuaries. It provides a forum to publish reports that focus on complex issues facing the National Marine Sanctuary System.
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