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 Tampa Bay, St. Joseph Sound and Clearwater Harbor but caution that the results may be due to the drought.
According to the District’s 2008 seagrass mapping study, seagrass acreage in Tampa Bay has increased nearly 1,300 acres since 2006. District studies show that since 2004 Tampa Bay continues to regain seagrass at an annual rate of two to three percent and now supports more seagrass than at any time measured since the 1950s. Tampa Bay currently has about 29,647 acres of seagrass.
According to the 2008 seagrass mapping study, the St. Joseph Sound/Clearwater Harbor has recorded a 16 percent change in seagrass.
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 can be found in waters around Egmont Key at 15 feet deep. 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 bay. Polluted runoff clouds water, preventing sunlight from reaching the underwater grasses. Additionally, the lack of rain made the water clear 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.
The District began its formal seagrass mapping program in the late 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 the Hillsborough County Environmental Protection Commission, provide assistance with field surveys.
In addition to an overall increase in seagrass, water clarity in Tampa Bay during the project was also the best it has been since record-keeping began in the 1970s. Data on water clarity is collected by the Hillsborough County Environmental Protection Commission from more than 60 sampling stations scattered throughout the bay.
“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/.