Seagrass

Significance of Seagrass beds

Seagrass beds provide habitat, nursery area, and food for ecologically and economically important fauna and flora. Some animals that directly graze on Florida’s seagrass are sea turtles, manatees, parrotfish, surgeonfish, sea urchins and pin fish. Many others such as, stingrays permit fish, pink shrimp and caridean shrimp enjoy living within or on the edge of seagrass beds because the seagrass provides cover and hosts invertebrates that these larger animals eat.   Research has shown that the greater the density of seagrass beds the more fish and invertebrates present in a location.

Seagrass requires good water clarity and quality to survive since they possess similar structures to terrestrial plants. They need sunlight to penetrate the water in order to perform photosynthesis. Therefore a lack of sunlight could result in seagrass depletion. Other factors that can result in seagrass loss are listed below.

Permit fish feeding on seagrass

Causes of Seagrass Loss*

Natural Disturbances

• Storms
• Floods
• Turbidity

Anthropogenic Disturbances

• Boating and Shipping Traffic: Propeller washing, propeller scarring and turbulence
• Dredging & filling activities
• Shading from structures, e.g. boathouses and docks
• Nutrient loading (eutrophication)
• Storm water runoff

Management of Seagrass Bed Health

• Stormwater control and nutrient management
• Preservation and restoration of upland and wetland buffers
• Prevention of disturbances
• Slow speed zones to prevent damage and sedimentation by boat propellers

Currently there are seven species of seagrass that live in the Indian River Lagoon. Six of these species of seagrass occur throughout the tropical Western Hemisphere. In Brevard County the most common species is the Halodule wrightii and the rarest species is Halophilia johnsonii to the south of the county. The Halophilia johnsoni species is only found in the coastal lagoons of eastern Florida, and it is listed as state endangered and federally threatened.

References for Seagrass:

http://www.utmsi.utexas.edu/people/staff/dunton/mns352d/lecture9.pdf*

http://www.sms.si.edu/IRLSpec/Seagrass_Habitat.htm **