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Seagrass beds in Tampa Bay, Florida, are a staple food source for wintering Florida manatees and a restoration priority for the region. The most common seagrass restoration typically requires taking plugs from healthy shoal grass beds, causing damage to the donor bed. Since shoal grass is a smaller seagrass species with less extensive root structures, grazing manatees pull out the leaves, shoots, rhizomes, and roots from the sediment, making it more difficult for seagrass beds to quickly regenerate.
Partnering with experts at Florida Fish & Wildlife Research Institute Seagrass Lab, Coastal Program biologists in Tampa Bay are experimenting with the use of turtle in seagrass restoration. Turtle grass has extensive rhizomes and roots that often remain in the sediment after grazing.
In 2022 and 2023, over 3,000 turtle grass seedlings were collected from beach wrack and cultivated in an aquaculture nursery near Tampa Bay. Trials were conducted to determine the best techniques for planting the seedlings so they have a high survival and reproduction rate and can be easily outplanted.
Each summer, approximately 1,000 juvenile turtle grass shoots were outplanted in shallow, unvegetated areas in Wolf Branch Creek. Seedlings were planted in plots surrounded by herbivory exclusion devices during the winter months to reduce grazing pressure as the transplants established. Monitoring of the outplanted turtle grass indicate an approximate 45% survival rate.
The use of turtle grass seedlings in combination with shoal grass to restore seagrass beds could accelerate the transition to a climax seagrass community and provide more abundant and robust foraging for manatees. These techniques can also serve as a blueprint for seagrass recovery in other parts of Florida and eliminate donor bed impacts associated with current transplant projects.
