Stetson Bank Long-Term Monitoring: 1993-2015
This report reviews historical studies conducted at Stetson Bank in the Gulf of Mexico and presents reanalyzed annual monitoring data from 1993 through 2015. The earliest known documentation of Stetson Bank was in 1930. Between then and 2015, over 40 studies examining the geological and biological components of the site were conducted. Stetson Bank is an uplifted, high relief, claystone feature associated with an underlying salt dome. It supports a well-developed community of tropical marine sponges and corals. The location of the bank provides marginal environmental conditions for coral reef development due to varying temperature and light availability. The fish community is similar to other Caribbean reefs, but has reduced diversity due to the site’s isolation, small size, and dynamic environment. The water column at Stetson Bank includes annual anomalies, which stress the biological communities. In the past, when anomalies were experienced in one or two parameters, biotic communities at Stetson Bank remained fairly stable, but when multiple anomalies occurred in the same year, significant changes were observed in the benthic biota.
The benthic community at Stetson Bank has undergone several significant shifts between 1993 and 2015, changing from a habitat primarily composed of hydrocoral and sponges to one dominated by macroalgae and sponges. These changes occurred in years when multiple environmental stressors affected the region. In addition to these rapid changes in benthic community, long-term declines in sponge cover and growth of macroalgae were also observed. The decline in the cover of sponges correlated with a decline in sighting frequency of spongivorous fish. Overall, the fish community was temporally variable, with sporadic recruitment events potentially contributing to this variability. Fish biomass at Stetson Bank is high, with piscivore biomass typically greater than herbivores, thus exhibiting an inverted trophic biomass pyramid.
benthic community, fish community, Flower Garden Banks National Marine Sanctuary, long-term monitoring, mesophotic coral ecosystem, Stetson Bank, water quality