Laguna Madre (United States)

Laguna Madre was formed about 3,000 years ago, after the stabilization of the sea level on the Texas Coast, culminating in the rise of Padre Island. The Baffin Bay extension is considerably older than Laguna Madre, and formed as a river valley during the Pleistocene epoch, over 12,000 years ago. Early peoples obtained oysters from the bay, which were eliminated due to changes in salinity after the full formation of Laguna Madre. The first people to encounter the new lagoon were most likely the nomadic Karankawa and Coahuiltecan Indians. The Spanish explorer Alonso Álvarez de Pineda is believed to be the first European to come in contact with Laguna Madre in the early 16th century, and is credited with giving it the name, which is Spanish for "mother lagoon". The area near present-day Port Isabel was used as a resort for Spaniards after watersellers came ashore in the late 18th century looking for freshwater supplies. A settlement known as Point Isabel was established at the location in the 1830s, and in 1853, the Point Isabel Lighthouse was constructed to overlook the lagoon. The city was named Port Isabel in 1928, and in 1954, the Queen Isabella Causeway, the longest bridge in Texas, was constructed across Laguna Madre to South Padre Island. A newer bridge was built in 1974, Port Isabel had 4,865 residents during the 2000 census. The cut allows an influx of seawater into the Lower Laguna Madre to improve the fishing and shipping industry of Port Mansfield. The community had 415 residents in 2000. ==Features==

(dark green), Baffin Bay (light blue), Cayo del Grullo (pink), Upper Laguna Madre (yellow), Laguna Salada (dark brown, directly to the left of Baffin Bay) (red), South Bay (light green) Laguna Madre is found between the mainland of South Texas and Padre Island. At this location between the Nueces River and the Rio Grande, the climate is dry and it is sometimes referred to as the Wild Horse Desert. The western shore, a large part of which is included in the King Ranch, is usually marked by sand dunes, yucca, prickly pear, century plants and an occasional oak tree bent by the wind. and is crossed by the Queen Isabella Causeway. Included in the Lower Laguna Madre is Red Fish Bay, which is found along the shoreline of the King Ranch, south to Port Mansfield. Together with its extensions, the lagoon forms one of seven major estuaries along the Gulf Coast of Texas. and joins the upper and lower stretches. Because of the high salinity, it holds the distinction as one of the Earth's six hypersaline lagoons/bays, the others being Sivash in Ukraine, Laguna Ojo de Liebre on the west coast of Baja California, Spencer Gulf and Shark Bay in Australia, and the Laguna Madre of Tamaulipas, which is sometimes grouped with the Laguna Madre of Texas as one system. The reasons for the lagoon's hypersalinity include its isolation from other bodies of water, the lack of a significant river source, and a high rate of evaporation caused by its shallowness and dry climate. Its salinity was even greater before the Port Mansfield Gulf Channel was dredged on Padre Island, which allowed a larger amount of seawater exchange. However, very little water exchange occurs at all; every second only of water flows into the lagoon. Rainwater from tropical storms and hurricanes is the only significant fresh water the bay receives. The salinity is greatest in the Lower Laguna Madre, where it averages around 45 ppt. ==Ecosystem==

The Laguna Madre is one of the most important and unspoiled lagoon ecosystems in Texas. Fish, shrimp and crab, which feed the bird populations, depend on the lagoon and its plentiful beds of seagrass for survival. The seagrass of Laguna Madre accounts for 80% of all seagrass found off the Texas Coast; however, it is threatened by brown tides caused by poor circulation and dredging. An influx of seawater can sometimes replace the vital seagrass with oyster beds. Birds Many fowl migrate and live around the lagoon including 75% of all redhead ducks. Other birds in the area include the peregrine falcon, piping plover, roseate spoonbill, long-billed curlew, crane, egret and the brown pelican. Sea turtles and dolphins can be found in the bay, while cattle, white-tailed deer, nilgai and bobcats can sometimes be seen near the shore. ==Industry==

The ports of Port Isabel and Port Mansfield rely on the fishing and shrimping industries. In the 1960s, Port Isabel averaged a catch of of shrimp annually, which accounted for 65% of the entire production in Texas. In Port Mansfield, the fishing industry has greatly expanded with the opening of the Port Mansfield Channel, allowing a steady accumulation of red fish, brown shrimp, and flounder. Because of the bay's environmental protections, very few manufacturing plants have been constructed in the area. Following an environmental campaign, the Valero Energy Corporation constructed an oil and gas pipeline from Corpus Christi to the Rio Grande Valley to decrease the shipment of oil and gas along the Intracoastal Waterway, greatly diminishing the chance of a spill. Activists have likewise railed against a proposed wind turbine farm off Baffin Bay, due to the potential harm to the scenic shores and the bird populations. The tourism industry is also a mainstay for communities on the lagoon. Beach-goers must pass the Laguna Madre to reach the prime beaching destination at both North and South Padre Islands. Fishing has drawn tourists to Port Isabel, where the Texas International Fishing Tournament has been held since 1934. Visitors also flock to Bird Island off the western coast of Padre Island, for windsurfing, kayaking, and other water sports. The SpaceX launch site and company town of Starbase is located at the extreme south end on South Bay. ==References==