Sarasota News Events: (OurTownSarasota has supported the Sarasota Bay Estuary Program with PSA’s for the past seven years.)
Report by the Sarasota Bay Estuary Program Sarasota Bay Waters Improve
We, SBEP, went out to the bay to do a final verification of the 2024 seagrass maps, produced by our friends and colleagues with SWFWMD. In my last Director’s Note, I highlighted how our 2024 Ecosystem Health Report Card showed that Sarasota Bay continued to show signs of recovery over the past few years – Director’s Note: 2024 Ecosystem Health Report Card update. As a reminder, our Report Card includes four metrics: the amount of nitrogen in the water column, the amount of floating microscopic algae in the water column, the amount of macroalgae across the bay, and the acreage of seagrass coverage. Here, we are going to focus on the results of the seagrass mapping effort carried out by the SWFWMD. The SWFWMD has been mapping seagrass meadows every two years from Tampa Bay down to Estero Bay since the late 1980s, with St. Joseph Sound (close to Tarpon Springs) added in the late 1990s.
Seagrass meadows play an important role as a source of food and/or refuge for the vast majority of recreationally and commercially important species of fish, crabs, and shrimp in Florida, and they also serve as a food source for manatees and green sea turtles. While direct impacts from channel dredging can cause losses, the vast majority of losses in Florida’s estuaries have been linked to impacts from degraded water quality. As such, seagrass coverage is a sort of “canary in the coal mine” and trends in the coverage of seagrass meadows have been used for decades as a holistic indicator of water quality conditions in various locations, including the Chesapeake Bay, Tampa Bay, Indian River Lagoon, and Sarasota Bay.
With that as background, how did our 2024 seagrass mapping efforts turn out? Well, to be direct here – pretty damn good!
Between 2022 and 2024, our seagrass meadows increased by 1,912 acres, a 19% increase! While the majority of the increase occurred in the open waters of upper Sarasota Bay (from the Ringling Causeway up to Manatee Avenue) every part of the bay had increases. Palma Sola Bay added 39 acres, while the lower bay (Roberts, Little Sarasota, and Blackburn Bays) added a total of 40 acres. In the Lower Bay, the losses of seagrass started back in 2014, and the results from 2024 are the first evidence of an increase in a decade. The 19% increase across the bay is the second biggest increase seen in over 30 years, and while we are still 12% below the peak coverage we had in 2016, we now have 36% more seagrass than we had 36 years ago, in 1988. So, what’s the benefit of having such an increase in seagrass coverage? Well, the Smithsonian Institute, which has had a research lab along Florida’s Indian River Lagoon for at least 40 years, concluded that the average acre of seagrass can support approximately 40,000 fish – Seagrass and Seagrass Beds | Smithsonian Ocean. Multiply 1,912 acres of NEW seagrass by 40,000 fish per acre, and you can come up with a defensible conclusion that we’ve added enough seagrass habitat to support more than 75 million fish.
Two figures best display the turnaround we’ve been able to bring about here in Sarasota Bay.
The photo on the left shows (in red) the 22% decrease in seagrass coverage that was documented between 2018 and 2020 in the Upper Bay. The areas of seagrass loss in the Upper Bay were widespread – mostly north and south of Longbar Point, but also in the area east of southern Longboat Key and offshore of the mainland shoreline between Bowlees Creek and Whitaker Bayou. The years of 2018 to 2019 had some of our worst water quality in the bay, including the impacts of a red tide event that exceeded a year in our region. Was this by chance alone – some event not connected to human activity? Hardly, 2018 was the worst year on record for wastewater overflows in our region, and before those overflow events occurred, we likely overloaded our reclaimed water systems with high-nutrient treated effluent, in an attempt to prevent those overflows from occurring.
Now, compare that map to the one on the right, which shows (in green) the amount of new seagrass meadows that have been added in the last two years. In the same areas where much of the losses occurred between 2018 and 2020, we’ve seen big increases between 2022 and 2024. This wasn’t really a surprise to us, as we have been anticipating a substantial increase since last spring – Director’s Note: Reasons for optimism – with a few caveats.
But why did this increase happen? Because we’ve had multiple years of improving water quality, as we highlighted nearly two years ago – Director’s Note: FDEP determinations of water quality trends. But why did our water quality get better? Because, we believe our local government partners have invested about $300 million in projects that have upgraded our wastewater infrastructure, retrofitted over 6,000 acres of our watershed with regional stormwater treatment systems, and – importantly – we have spent considerable efforts to inform our public about the role that they can play in helping to reduce their own contributions to bay-wide pollution – Director’s Note: Honing in on the basis for recent trends…
There might be some skepticism about the good news that we often bring to the public, which is understandable. However, the determination that our water quality had improved sufficiently to remove us from FDEP’s Impaired Waters List for nutrients was made independently by FDEP staff. And the seagrass maps were independently developed by the staff of the SWFWMD. All in all, the consensus that Sarasota Bay’s health is improving – and substantially so – has been independently reached by the SBEP, our consultants at ESA, FDEP and now SWFWMD.
This is good news – very good news. And while our efforts have been good for Sarasota Bay, they can also help, perhaps, to serve as an example for other coastal communities in Florida and elsewhere. And to perhaps help that along, we have produced a webpage that summarizes what we’ve seen in Sarasota Bay, what happened, how it happened, and why it matters – Seagrass & Algae | Sarasota Bay Estuary Program
The SBEP works best when we don’t labor to find the perfect solution or the world’s best ecological models, but when we develop enough good science to help identify the types of projects and programs needed to restore and/or protect our water quality and natural resources. For several years now, we have been citing the value of an approach that we call “biased towards action”. And now, the results are starting to pile up, indicating that such an approach has been useful.
There are more challenges out there for us to deal with, and this bay is not at all “pristine”. We still have, for example, a lot of macroalgae in the bay. But we seem to have been able to handle the multiple impacts from 2024’s active hurricane season not only without collapsing, but it seems we didn’t even lose the seagrass increases we have documented the last two years. A cleaner bay is a more resilient bay, and Sarasota Bay is moving in the right direction. With a continued focus on nutrient management, habitat restoration, and public education, there’s no reason why this positive trend can’t continue.
