Speckled trout cruise just beneath the water’s surface. The pink flash of a Roseate spoonbill can be seen overhead. Periwinkle snails climb the smooth cordgrass, just beyond the reach of a hungry redfish.

Where land becomes sea, and freshwater meets salt, is one of the most productive biological systems.  On the southeast Texas coast, it includes one of the most important recreational destinations – the Gulf of Mexico.

As one moves toward the coast, marshes, bayous and rivers give way to flats and open water.  The mixing of these waters, salt and fresh, is what sustains many varieties of finfish, oyster reefs, and other shellfish, including shrimp and blue crabs.

Known as the “nurseries of the sea,” estuaries are the ocean’s protected areas.  Here, complex food chains include everything from microscopic organisms to sportfish to shore birds to fur-bearing mammals to humans.

To read more about Estuaries and Bays, download our atlas! 


Galveston Island State Park

Sea Center of Texas

Matagorda Bay Nature Park

Texas State Marine Center, Palacios

Artist Boat

Download Houston Wilderness' List of Ecoregion Sites for information on sites in all 10 ecoregions. 


1) As frozen water from the ice age began to melt, sea level in the Gulf of Mexico rose over two hundred feet and flooded river valleys that had cut into the shelf. Three of the flooded river valleys became great estuaries of the upper Texas coast: the Sabine Lake system, the Galveston Bay system and the Matagorda Bay system.

2) Sabine Lake receives its fresh water from the Sabine and Neches rivers while Galveston Bay is fed by the Trinity and San Jacinto rivers. Matagorda Bay receives inflow from both the Colorado and Lavaca rivers.

3) San Louis Pass has 20 percent of the tidal flow for all of Galveston Bay moving through it.

4) An estuary, such as Galveston Bay, converts as much carbon dioxide into plant material as does a tropical rainforest.

5) The bays of the Houston Wilderness area receive the highest inflows of any estuaries of the Texas Coast.

6) Galveston Bay is the national leader in the production of oysters while Port Arthur, Galveston and Palacios lead the Texas coast in shrimp landings.

7) Together, the Sabine Lake, Galveston and Matagorda bays provide over half of the blue crabs on the Texas coast.

8) Recreational fishing is a large industry in these estuaries; in Galveston Bay fishermen have the highest catch per unit of effort by sport fishermen.

9) Oysters are the best example of the adaptability of estuaries; their reefs are the center of biological diversity in our bays. Oyster reefs provide habitat for smaller fish, hunting grounds for predators and, where the reef extends above the water line, a fishing station for coastal birds.

10) Each season is a resource for new and exciting encounters with coastal birds. During the winter months, sea ducks like mergansers and buffleheads can be found around the bay systems along with wintering white pelicans and native brown pelicans. In the spring there is nothing like seeing the nesting sites of colorful costal birds like the roseate spoonbill.


Banner Photo by Deborah January-Bevers