Slight decline documented in Charlotte Harbor
Scientists with the Southwest Florida Water Management District’s Surface Water Improvement and Management (SWIM) Program continue to see an increase in seagrass growth in Sarasota Bay and Lemon Bay.
According to the District’s 2008 seagrass mapping study, seagrass acreage in Sarasota Bay has increased nearly 2,786 acres since 2006, a 28 percent increase. This increase follows a seven percent increase seen between 2004 and 2006. Lemon Bay also saw a five percent increase in seagrass acreage or 149 acres since 2006.
Seagrass is an important marine habitat and a valuable tool for scientists throughout the state of Florida. Seagrass generally grows in waters less than six feet deep, but in certain portions of Sarasota Bay can be found at depths of 12 feet or more. Seagrass is an important barometer of a bay’s health because it requires relatively clean water to flourish and serves as “the nurseries of the bay,” sheltering and supporting a variety of juvenile fish and other marine creatures.
Kris Kaufman, a District environmental scientist, cautions that the improvements may be due, in part, to the ongoing drought, since less rain means less stormwater runoff flowing into the bays. Polluted runoff clouds water, preventing sunlight from reaching the underwater grasses. Additionally, the lack of rain made the water clearer and provided excellent conditions when the aerial photos for the study were taken. This allowed for better views of the seagrass in deeper waters that are often hard to see clearly.
While Sarasota Bay and Lemon Bay both saw increases, Charlotte Harbor saw a five percent decrease in seagrass acreage. A majority of the losses are seen at the edges of seagrass beds along the East Wall.
These three southern most SWIM waterbodies have maintained relatively stable seagrass acreages since the District seagrass mapping program began in the 1980s. As part of the program, SWIM scientists assess seagrass coverage in five gulf coast estuaries. Every two years maps are produced from aerial photographs and then verified for accuracy by conducting field surveys. The results are used to track trends in seagrass in estuaries throughout southwest Florida and to evaluate ongoing water quality improvement efforts.
The District works with a consultant to complete this project and several state and local agencies, including Sarasota County, provide field work to verify elements of the maps.
In addition to an overall increase in seagrass, water clarity has improved over the last few years. Data on water clarity is collected by Manatee and Sarasota counties and Mote Marine Laboratory for the three systems.
“Results of our seagrass mapping project indicate SWIM and other stormwater improvement projects lead to healthier water bodies,” said Jennette Seachrist, SWIM Program manager. “Our goal is to continue to reduce nutrient loading and improve water quality.”
For more information about the District’s SWIM Program, please visit the District’s web site at http://www.swfwmd.state.fl.us/projects/swim/.
To learn more about how you can help preserve Florida’s seagrass, which is critical to protecting marine life, water quality and Florida’s ocean-based economy, visit http://www.dep.state.fl.us/coastal/habitats/seagrass/.