Written by: Andrea Barber and Linda Walters: Department of Biology, University of Central Florida 2006 Brevard Zoo Conservation Fund Grant: $1,500
In recent years, intertidal reefs of the oyster in central Florida’s Indian River Lagoon have suffered extensive losses due to wakes from recreational boats. Wakes move oyster shells around creating dead margins, piles of shells on the seaward edges of reefs. Reefs with dead margins have reduced new oyster recruitment and biodiversity. The creation and enforcement of “no wake” zones around oyster reefs are unlikely. Thus, there was an urgent need for an alternative restoration strategy to prevent further decline of the remaining healthy, viable oyster reefs in this important estuary.
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We have developed a technique that we call “oyster mats” for our oyster restoration program in the IRL. These mats consist simply of a mesh base to which we attach oyster shells that have been drilled near their hinge. We have experimentally documented that 36 shells on a base that is 0.4 m2 is optimal for oyster recruitment as well as enhancement of local biodiversity. Why not just throw shells out into the lagoon as is done in many other oyster restoration projects?
One of the major reasons for the decline of intertidal oysters in the IRL is that live oysters and loose shell are redistributed by boat wakes. In many lagoon locations, this water motion pushes the oysters/shells above the high tide line, creating piles of dead shells (= dead margins). No new oyster recruitment can occur on these dead margins. Many reefs with dead margins are also significantly smaller than they were in historical aerial photos, while reefs in less trafficked areas and no dead margins show no change in size. One of the major goals for this project was to involve as many community volunteers as possible to enhance awareness of the beauty and importance of oysters in the IRL. Knowing that it is not practical to take many hundreds of people to the oyster reefs, we are able to bring a hands-on restoration project to them. Between October 2006 and the present, 816 volunteers have contributed over 1200 hours to collecting shells, drilling shells and making mats. Recent volunteer groups have included Brevard K-12students, local Homeowners Associations, Merritt Island National Wildlife Refuge and State Park volunteers. Since our project start in 2005, over 5000 central Floridians have been involved and we hope to expand this in the future!
In 2006, the Brevard Zoo Conservation Fund provided us with funds to help purchase supplies that we are currently using to experimentally determine the most effective restoration protocol for oyster reefs in locations with significant recreational boating activity. We are focusing our initial efforts in Canaveral National Seashore (CANA) at the request of John Stiner, Resource Management Specialist for CANA, who was the first to notice the formation of dead margins on oyster reefs in the 1990s. We are on schedule to complete this 1-year experiment in early March 2007. Next we will analyze the data and use the optimal restoration technique for our first largescale restoration deployment scheduled for April/May 2007. Our ultimate goal is to restore all reefs in CANA (approximately 60) that have been damaged by wakes from recreational vessels and we are very grateful for support from Brevard Zoo Conservation Fund for helping us achieve this goal.