SeaGrant Logo

July 04, 2020

This page last modified:
March 21, 2001

Boating Impacts to Monroe County Seagrass

by Christine Rapozo

University of Florida/Monroe County Cooperative Extension

Florida Bay Education Project

Seagrasses are considered to be the most productive communities in the world, according to Dr. Jay Zieman of the University of Virginia. Seagrass beds provide shelter and sustenance to a variety of larval and juvenile marine and estuarine animals and wading birds. Seagrasses also improve water quality by trapping pollutants and suspended sediments. As Florida's coastal population increases threats to seagrass communities increase.

An estimated 70% of seagrasses in Florida Bay have been lost due to water quality and timing and distribution problems. Researchers estimate an additional 2%, or 30,000 acres, of Monroe County seagrass beds have been damaged from boat propellers. Propeller scarring of seagrasses occurs when boaters attempt to motor through water that is too shallow for their boats. Propellers cut seagrass leaves, roots and stems and gouge sediments creating unvegetated, lightly colored, narrow furrows called prop scars. These furrowed trenches can take 2 to 6 years to regrow to normal density depending on the species of grass, sediment composition and water quality. Is this 2% parcel worth caring about? If so, what can be done about it?

The University of Florida Sea Grant Florida Bay Education Project, Everglades National Park and the Florida Keys National Marine Sanctuary are trying to find out. They are sponsoring an interagency workshop at the Key Largo Public Library on March 25th that will focus on three questions: 1) What are the major causes of seagrass damage?; 2) What are the effects of seagrass damage to the Keys environment?; and 3) What should we do about it?

The goal of the "Seagrass Summit" is to combine local resources and expertise to identify the types of education and outreach programs which would be effective in increasing the public's awareness of seagrass dynamics, how to minimize boating impacts and other measures to reduce negative human impacts on seagrass beds. Experts have been invited to discuss the magnitude and distribution of damaged seagrass beds. Dr. Mike Durako, University of North Carolina at Wilmington, will give an overview of the biology and ecology of seagrass habitats. The causes and distribution of seagrass damage in Monroe County will be discussed by a panel including Robert Brock, Everglades National Park, Jay Zieman, University of Virginia, Rich Jones, Monroe County Marine Resources, Susan White, Key Deer National Wildlife Refuge, Janice Duquesnel, Florida State Parks and Curtis Kruer, Florida Audubon Society. Billy Causey, Superintendent of the Florida Keys National Marine Sanctuary, will provide insight on the development of the Coral Reef Awareness Program implemented several years ago by the Looe Key and Key Largo National Marine Sanctuaries.

The Florida Bay Education Project is a program of Florida Sea Grant and the University of Florida Cooperative Extension Service. With over 100 research projects underway within Florida Bay, the Project serves as a source of information, communication and education for the public on Florida Bay science.

For more information contact the Florida Bay Education Project at 305-852-3592. Additional information on a variety of topics is available from the University of Florida/Monroe County Cooperative Extension Service, 5100 College Road, Stock Island or call at 292-4501; fax: 292-4415; email: or visit our web site Our services are free and available to all without regard to race, color, sex, or national origin.

The Florida Bay Education Project is an archived site. For more information go to NOAA's South Florida Ecosystem Education Project at