Seagrass Distribution in the Pensacola Bay System, Northwest Florida

Aerial surveys of seagrass coverage in the Pensacola Bay system (PBS) have been conducted during 1960, 1980, 1992 and 2003. This report summarizes the results for the 2003 survey and compares the results to those previously reported for other surveys. The estimated coverage of seagrass for the PBS during 2003 was 1,654 ha. Continuous and patchy coverages ranged from 0 to 684 ha and 11 to 543 ha, respectively, for five PBS subsystems. In 2003, the majority of seagrass coverage occurred in Santa Rosa Sound (76%). Declines in total coverage occurred for East Bay (93%) and Escambia Bay (75%) whereas increases were observed for Pensacola Bay (32%) and Santa Rosa Sound (8%). The approximate 9% decline (about 160 ha or 395 a) in total coverage since 1992 represents an estimated 7 to 8 million dollar loss in ecological services. The changes in coverage are likely due to naturally occurring and anthropogenic factors but it is not possible to differentiate the relative contributions of these factors alone and in combination on seagrass distribution. The ability of seagrasses to exist long-term in Florida’s fourth largest estuarine system is uncertain due to the adverse effects of rapid urbanization in the watershed. Active resource management which includes more frequent in-situ monitoring and aerial assessment and the availability of relevant water and sediment quality criteria protective of submerged aquatic vegetation are needed to prevent future declines