Meeting Abstract
We document significant declines of intertidal oysters within Mosquito Lagoon, Florida, with the most serious losses occurring within Canaveral National Seashore, where reef acreage has decreased by 40% since 1943. In these shallow, microtidal waters, piles of bleached shells extend above mean high water where live reefs were historically located. Dead reefs begin as dead margins that are created as sediment erodes from the base of the seaward oyster clusters, dislodging clusters that then wash into piles above the intertidal zone. Dead margins transform into dead reefs within a few years as the dead margins migrate toward shore (mean rate: 1.3 m/yr) covering over additional live oysters. Eventually only shells remain (= dead reef) and this shoreward migration continues until all shells wash up into the marsh and no intertidal reef footprint remains. Boat wakes from recreational vessels are an important source of initial oyster cluster dislodgement, subsequent shell movement, and, thus, dead reef formation. In 2007 we began restoring oyster reefs negatively impacted by boat wakes and have now developed a method that is transferable to other locations experiencing similar problems. 68 oyster reefs have been restored by UCF/Brevard Zoo/TNC and over 38,000 community volunteers. Our methodology that couples dead margin leveling with placement of stabilized shell on the leveled substrate is exceeding our structural and functional objectives as: 1) no dead margins have reformed, 2) recruitment on 2007 reefs continues to increase and now averages over 115 live oysters/0.25 m2, and 3) seagrass recruited seaward of 37% of the restored reefs. Overall, our project has been exceptionally successful in terms of oyster recruitment, habitat improvement, and community engagement.
