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The past two decades have seen a marked decline in Texas oyster populations — a result of changes in water quality and pressure from commercial oystering and dredging for use as inexpensive roadbed material and concrete manufacturing. In addition, a decrease in freshwater flows into Texas bays and estuaries has increased the concentration of salt in the water, decimating living oyster reefs.
To combat that decline, the Conservancy in April launched an ambitious oyster-reef restoration project in Copano Bay on the coast near Rockport. More than 200 cubic yards of oyster shells were ferried into shallow water by barge and blown into the bay by fire hose within a one-acre patch where an oyster bed once rested. Plans are in the works that might double or triple the size of the existing reef with additional oyster shell.
After settling on the bay floor, the shells will form a substrate — known as “cultch” — that will then be colonized by larval oysters, called “spat.” The spat will adhere to the cultch, essentially binding the shells together into one great biomass that will provide habitat for a variety of marine life, including prized juvenile sport fish such as red drum and speckled sea trout. American oystercatchers and many other birds also rely on exposed oyster reefs, especially during winter.
Oysters play a particularly vital role in coastal ecology. Along with other shellfish, oysters act as suspension feeders — organisms that strain microscopic algae growing suspended in surrounding waters. By removing this suspended organic material, oysters effectively filter the water (up to 50 gallons a day per oyster), thereby maintaining good water quality in bays and estuaries. Intact oyster reefs also function as natural breakwaters that protect shorelines and inland human communities from hurricanes and tropical storms by dissipating storm surge and wave power.
According to the Texas Department of Agriculture, Texas produces the second-largest oyster catch in the United States and accounts for 13 percent of the nation’s total production. In 2006, the harvest amounted to nearly 5 million pounds. In total, more than 270 million pounds of oysters are estimated to have been reaped by commercial oystermen for mostly Texas consumers.
The Copano Bay project site will be closely monitored over the next several months by Conservancy staff and partners, including experts from the Harte Research Institute for Gulf of Mexico Studies, to ensure the spat are successfully colonizing the reef and out-competing other sea life, such as mussels and barnacles.
This project is part of the Conservancy Shellfish Restoration Network, an ongoing effort to restore reefs for shellfish in various locations throughout the coastal United States. If successful, the Copano Bay reef project could serve as a model for future restoration efforts along the Gulf Coast and other coastal regions.
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Nature picture credits (left to right, top to bottom): Photo © Mark Gagliano (Mark Dumesnil); Photo © Danny White/TNC (Oysters); Photo © Austin Business Journal (Laura Huffman); Photo © Rebecca Flack/TNC (Frio River); Photo © Danny White/TNC (Oysters); Photo © Clay Carrington/TNC (Attwater's prairie chicken); Photo © Will van Overbeek (Richard Garriott); Photo © David A. Williams (prairie grass); Photo © Janet Haas (pronghorn); Photo © TNC (Lennox Woods Preserve); Photo © Lynn Mc Bride/TNC (Caddo Lake); Photo © Insite Architects (Pearl Brewery Design); Photo courtesy of Dick Bartlett (Dick Bartlett); Copano Bay video courtesy KZTV Corpus Christi
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