From Sarasota Bay Estuary Program Director Dave Tomasko:

As you know, the upper and lower portions of Sarasota Bay are different from each other in important ways. That portion of the bay north of the Ringling Bridge is much wider and contains more and deeper water than the area between Ringling Bridge and Venice Inlet. Conversely, the watershed is much larger in the lower bay than in the upper bay. For example, Philippi Creek’s watershed is about 1/3rd of the total watershed for the entire bay. As a result, the watershed-to-open water ratio is much higher in the lower bay than in the upper bay. That is one of the reasons why the water in the lower bay does not look like the water in the upper bay, nor did it look like the upper bay in pre-development times, most likely. That is also one of the reasons why our Ecosystem Health Report Card does not compare, for example, Little Sarasota Bay against Palma Sola Bay, or Blackburn Bay against the open waters of Upper Sarasota Bay.

Instead, our Report Card compares each bay segment against what it was during the period of 2006 to 2012. Why those years? Well, because we have actual data on all the four components of our Report Card (in the lower bay) as far back as 2006. The limiting factor, in terms of how far back we can go, is the data set for macroalgae. There’s been a lot of focus on macroalgae lately – not just here but across the state and globally, so much so that we had a three-day workshop on macroalgae three years ago -2021-Florida-Macroalgae-Workshops-Report.pdf. If you don’t have data, all you can do is wave your hands around about what you think it used to be like. We don’t and won’t do that. And so we have a Report Card that goes back as far in time as our macroalgae dataset.