The Book of Texas Bays

24. Laguna Atascosa

247 Gib Little cut the motor and coasted to the edge of the Gulf Intracoastal Waterway and into a small side bay, shallow and full of seagrass. The shoalgrass glistened in the early morning sun, the underwater meadow revealed in the clear water of the lower Laguna Madre. The key to fly fishing for reds is to be quiet and observant. We were looking for nervous water—water with a surface pattern distinct from that produced by the prevailing wind. Gib took his position at the front of the boat, legs extending over the side, pulling the boat forward with his feet in the shallow water. As I looked across the water for tailing redfish, the early morning embraced me. I was fishing with my eyes, looking for movement, all senses alert. I noticed the gray sentry, the great blue heron, standing at the side of the mangroves, suddenly stabbing a careless mullet. Black skimmers flew slowly across the surface, their orange beaks extended like scissors into the water. I looked to one side in response to a splash and saw a Sandwich tern heading back up to the heavens, seemingly stopping in midair to shake its meal down. Laguna Atascosa Laguna Atascosa 24 The Laguna Atascosa National Wildlife Refuge is adjacent to the Laguna Madre and lies across from South Padre Island and the southernmost of the tracts now owned by the Texas Nature Conservancy. The large sandy flats between Highway 100 and Highway 1792 north of the Brownsville Ship Channel were recently purchased by the Conservation Fund and will become part of the national wildlife refuge system. At lower right are the South Bay Coastal Preserve and the lands that are now part of the Lower Rio Grande Valley National Wildlife Refuge. GULF OF MEXICO LAGUNA MADRE ARROYO COLORADO SOUTH PADRE ISLAND SOUTH PADRE ISLAND PRESERVE LAGU N A ATASCOSA N W R Chapter 24 : Laguna Atascosa 248 The Book of Texas Bays Suddenly Gib whispered, “There’s a pod just to the left of the sun.” At first I couldn’t see them, but then the tails appeared, ghostlike, wisps of motion flitting to and fro, like lace above the surface. The fish were feeding on crabs and shrimp in the seagrass; we had not bothered them yet, and we intended to keep it that way. Along with tidal flats, seagrass is what makes Laguna Madre so productive. Four main types of seagrass are found in the laguna: widgeon grass, shoalgrass, turtle grass, and manatee grass. Widgeon grass, an excellent waterfowl food, is often found interspersed with shoalgrass, the primary food source for redhead ducks. Turtle grass is found in slightly deeper areas and is grazed by sea turtles. Manatee grass supplements the sea turtles’ diet but is found in less disturbed, more pristine areas.1 Seagrasses require clear water conditions and higher salinities, which are found primarily in the southern bays. The Laguna Madre has by far the most, with over 180,000 acres of submerged grasses (fig. 31).2 The next largest areas of Submerged seagrass in the Laguna Madre is an important habitat that must be protected in order to preserve productivity. Photograph by Jim Blackburn 249 Chapter 24 : Laguna Atascosa submerged vegetation are in the Corpus Christi Bay system, with approximately 24,000 acres. The San Antonio Bay system and the Aransas system have much less. Although some ducks and sea turtles eat the grasses, the most important function of the seagrasses—the reason they are a key component in the productivity of Laguna Madre—is that they provide habitat for the epiphytic algae that grow on their leaves. In turn the algae, primarily diatoms, provide food for a host of invertebrates , such as shrimp and crabs, which become food for higher predators. Human activities impact seagrasses, harming them sometimes in ways we are only beginning to realize. Walt Kittleberger is fighting the Corps over the impacts of their dredge disposal on the seagrass meadows, but recreational boaters cause substantial damage with their propellers as well. I have been in South Bay at the far southern end of the lower Laguna Madre at very low tide, when the water drains off and leaves the grass flats exposed. Water birds of all types descend on the exposed grasses, getting an easy meal. But the most prominent sight is the bare swaths cut in the grass—propeller scars. To get started after...