Sebastian News

Biological Monitoring Field Work Shows Resurgence of Threatened Johnson’s Seagrass

Marine ecologist Don Deis and his team from Atkins North America were recently out in the field ground-truthing seagrass beds shown in aerial photos taken this summer of flood tidal shoal just west of the Sebastian Inlet.  A full report is expected soon qualifying the different species, coverage of seagrass with comparisons to prior years, and noting the prevalence of prop scars from boaters in six zones surveyed by scientists.

“Don has been the lead scientist on this monitoring project for the last 12 years and we think that kind of consistency is important in accurately assessing the trends we are seeing,” said Martin Smithson, Sebastian Inlet District Administrator.

Seagrass beds around the Inlet are critically important habitat for a highly diverse groups of plants and animals and the Indian River Lagoon is the most biodiverse estuary in North America.  Seagrasses serves as a nursery for juvenile fish, shrimp and other marine life.  It is estimated that 70% of Florida’s marine recreational fish depend on seagrass communities during their life cycle.  Seagrasses are a food source for manatees, help maintain water clarity by trapping sediment and also stabilize the bottom with their root system.

The diversity of seagrass found in the Indian River Lagoon is greater than that found in any other U.S. estuary.  While recovery from a massive die-off in 2012 – credited in part to freezing temperatures, nutrient imbalances and devastating algae blooms – has been steady, but slow, Deis and his team found a healthy resurgence of a federally-listed threatened species, Johnson’s seagrass.  Originally identified in two of the Inlet’s six zones in the mid-1990s, Johnson’s seagrass is now prevalent in all six zones along with Shoal and Manatee seagrasses.

In a story in Vero Beach 32963 that documents the slow recovery and highlights challenges, Deis is quoted as being “heartened at the increased grass cover and appearance of manatees, juvenile green sea turtles, cow nose rays and bonnethead sharks he found in his recent survey.”

“Seagrass is a prime indicator of health of the Indian River Lagoon,” said Smithson.  “The District is not mandated to conduct this seagrass survey annually, though some projects in the past have required this type of monitoring.  It’s indicative of the Sebastian Inlet District Commissioners’ ongoing commitment to natural resource preservation and environmental protection.   We share our data and know there are a lot of groups working on the health of the Indian River Lagoon.  This is a way for us to be a part of the solution.”

One of the biggest, preventable threats to seagrass beds are prop scars from boaters.  In 2007, as part of a major project to extend the channel from the inlet to the Intracoastal Waterway, the Sebastian Inlet District installed signs reading “Caution. Shallow Water. Seagrass Area.” covering 145 acres of flood tidal shoal seagrass habitat.  After installation, seagrass monitoring reports show a steady decline in prop scars in the subsequent four years.

In addition, the Sebastian Inlet District also published and widely distributed a Sebastian Inlet Navigation Guide with a map showing the seagrass caution areas, clearly delineating the channel and markers for boaters and emphasizing the importance of seagrass beds.  Boaters are urged to stop their engines, tilt the motor and pole, drift or walk the boat to deeper water.  To download a copy of the Sebastian Inlet Navigation Guide map, click HERE.

For a complete copy of the Atkins North America report, once issued, or for more information, call (321) 724-5175.

The Sebastian Inlet District was created in 1919 as an independent special district by act of the Florida State Legislature, and chartered to maintain the navigational channel between the Atlantic Ocean and the Indian River.  The Sebastian Inlet District’s responsibilities have grown to include beach re-nourishment and dune repair as part of a state mandated sand bypass system, erosion control, environmental protection and public safety.  The Sebastian Inlet supports a rich and diverse ecological environment that is unparalleled in North America.  The Inlet is vital not only to the ecological health of the Indian River Lagoon, but it is also an important economic engine for local communities in the region.  Known as the premier surfing, fishing, boating and recreational area on the east coast of Florida, the inlet is one of only five navigable channels that connect the Indian River lagoon to the Atlantic Ocean.