STUART, Fla. — This week is National Estuaries Week, designed to raise awareness of these critical wildlife habitats.
Mark Perry, executive director of the Florida Oceanographic Center in Stuart, took WPTV NewsChannel 5 out from the Stuart city dock into the St. Lucie Estuary this week.
The estuary, a mixture of salty ocean water and fresh river water, is home to hundreds of species of fish and smaller invertebrates like crab.
"Estuaries are the nursery grounds for all of our fish, both commercial (and) recreational fish," Perry said. "Eighty to 90% of all the fish that we think about have their nursery stages right here in the estuary."
On this trip, Perry's on the hunt for sea grass, the lifeblood of the waterway.
What used to blanket the shallow part of the estuary is now much harder to find.
Perry gets out of the boat and reaches for the bottom, explaining what he's bringing up with his hands.
"This is the grassalaria, it's a natural kind of brown, floating algae, and then here's the sea grass," he said. "White rhizomes are the root system and then these are the blades that come up off the bottom."
The sea grass is not as dense as he'd like.
Fragments are collected and brought back to the Florida Oceanographic Center's nursery, where they are weaved into fiber mats to be replanted on the seafloor.
Although it wasn't a lost summer with massive freshwater discharges from Lake Okeechobee creating algal blooms, not all is well in the St. Lucie Estuary and Indian River Lagoon. Volunteers with the Florida Oceanographic Society have been giving this body of water pretty poor grades.
Weekly water tests are done throughout the estuary and recent tests have fallen in the satisfactory or poor range.
Salinity, or the saltiness of the water, is also at the lower end in the middle estuary. That's not good for oysters.
"This area of the St. Lucie, we used to have 470 acres of oyster reefs back in the 1940s, and we're down to less than 20," Perry said.
It's a delicate ecosystem under constant threat. There have been no major algal blooms so far this year, but one tropical system could upend a waterway trying to get its sea legs again.