Studies of Turtle Grass Reproductive Success in Tampa Bay

By Sheila Scolaro and Mike Poniatowski, Ecosystem Assessment and Restoration

As part of a NFWF- funded study, we are investigating the reproductive success of turtle grass (Thalassia testudinum) in panhandle estuaries and in Tampa Bay.

Turtle grass and other seagrasses are land plants that moved back into the ocean over geological time. As a result, they produce flowers that look a lot like chickweed (Stellaria sp.) that appears in yards each spring. Seagrasses spread asexually by vegetative fragments (shoots and rhizomes) and sexually by seeds or, in the case of turtle grass, viviparous seedlings.  Male and female flowers are on separate Thalassia shoots, and pollination is haphazard.  Thirty years ago, FWRI scientists Mark Moffler and Mike Durako determined that seedling production was very limited here in Tampa Bay.

This study is important because, in many areas where seagrasses have been lost in the past, recruitment might limit seagrass recovery.  Our study is just beginning, but we have made some preliminary observations.

Here in Tampa Bay, flowering is very patchy in time and space and flowering activity is most common in spring. Interestingly, flowers are more common (or maybe more easily seen) in turtle grass beds with lower shoot densities. As reported by Moffler and Durako, we have also seen that successful production of fruits and seedlings is uncommon in Tampa Bay, but we don’t know why that’s the case.  As we continue this study in 2017, we will visit as many spots around Tampa Bay as we can to find Thalassia flowers and follow those plants through the summer to determine success in seedling production and establishment.  We will also carry out parallel studies in Panhandle estuaries.

Please record locations and email if you see turtle grass flowers next spring.