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Update Regarding Weeki Wachee River Submerged Aquatic Vegetation Restoration Project Five Months Post Installation
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BRIEF OVERVIEW
To assist in restoration and enhancement efforts, from May 27, 2025, through May 30, 2025, a total of 43,950 Mechanical Planting Units (MPUs), 660 four-inch peat pots, and 132 GrowSAV Herbivory Exclusion Devices were installed throughout the river between the state park boundary to the north, and Rogers Park to the south.
The fifth monthly maintenance event for the Weeki Wachee River SAV Restoration Project occurred on October 24, 2025. The GrowSAV™ Herbivory Exclusion Devices exhibited light to moderate levels of biofouling, consisting mainly of settled sediments and attached filamentous algae. Sea & Shoreline biologists removed biofouling from the top and side mesh on mask and snorkel using stiff-bristled scrub brushes. Five months after installation, both unprotected and protected planting units are showing very encouraging signs of growth and expansion throughout the river. It is estimated that V. neotropicalis is present in 110/132 (83%) of the GrowSAV™ Herbivory Exclusion Devices, with coverages ranging from 2 to 4 on the Braun-Blanquet coverage scale.
The overall survival rate of protected units has decreased since the last maintenance event. After the recent King Tide event, it is evident that protected units located at the most downstream site (Site 5) suffered from the saltwater intrusion. Blade tissue of protected units at Site 5 was completely gone, and the only plant material was found underneath the top layer of sediment. These planting units will be monitored for any signs of regrowth.
It is recommended that supplemental planting take place at Site 5 to help jumpstart the recovery of planting units in this area. Planting units used at Site 5 will be comprised of a more salt tolerant variety of Vallisneria which will be able to withstand the salinity fluctuations that this area experiences. Maintenance will continue for the next seven months, with the sixth event taking place in November 2025.
FINANCIAL IMPACT
None at this time.
LEGAL NOTE
Not applicable.
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RECOMMENDATION
For informational purposes only, no action is required from the Board.