Twenty priority sites were identified, only one of them located within Mexico. The Laguna Madre de Tamaulipas priority site is described together with the other two priority US priority sites as a system.
1. Laguna Madre de Tamaulipas Principle targets: Seagrasses, tidal flats, Kemp’s ridley turtle, intertidal shrub/forest (mangrove) Principle stresses: direct target destruction (overfishing) 2. Lower Laguna Madre Principle targets: Seagrasses, tidal flats, Kemp’s ridley turtle, dwarf seahorse Principle stresses: Nutrification (from Arroyo Colorado), pollution (from Arroyo
Colorado), direct development) 3. Upper Laguna Madre Principle targets: Seagrasses, tidal flats, Kemp’s ridley turtle Principle stresses: Nutrification target destruction
The Laguna Madre of Texas and Tamaulipas is the only set of coastal, hypersaline lagoons on the North American continent and one of only five worldwide. Extending along 277 miles of shoreline in South Texas and northeastern Mexico, the lagoons are separated by 47 miles of Rio Grande Delta. Each lagoon is about 115 miles in length and each is further divided into subunits, the upper and lower Laguna Madre in Texas, separated by the Land-Cut tidal flats, and the northern and southern Laguna Madre de Tamaulipas, separated by the El Carrizal tidal flats. The lagoons are protected on the east by barrier islands and peninsulas, and bound on the mainland side by vast cattle ranches, farmlands, and the brush country of the Tamaulipan Biotic Province. South Padre Island is a nesting area for Kemp’s ridley turtles.
The historically recorded extreme salinities of over 100-ppt have been greatly moderated in recent decades due channel dredging and the cutting of passes. There has been less dredging in the Laguna Madre de Tamaulipas, and it has salinities closer to historical levels than the lagoons in Texas.
In Texas, almost 80% of all seagrass beds in the state are found in Laguna Madre and the historically, highly productive commercial fisheries have now given way to some of the best recreational fishing for red drum, black drum, and spotted sea trout in North America. In Tamaulipas, a boom and "bust cycle" of great fishery production alternated with briny, almost sterile waters before the 1970's.
The Laguna Madre also has the most extensive wind-tidal flats and clay dunes in North America. Wind-tidal flats occupy 354 miles of shoreline in the Texas Laguna Madre and 196 miles in Tamaulipas. A unique strain of oysters, adapted to the high salinity conditions of Laguna Madre, are found in South Bay, the southernmost portion of the lower Laguna Madre in Texas (Tunnell and Judd in press).
The highest priority of these three sites should be the seagrass and tidal flat communities of the Lower Laguna Madre. At present, Mexican partners are collecting and analyzing spatial information on the distribution of submerged habitats in the Laguna Madre de Tamaulipas, and this effort is expected to identify a smaller area of high priority sites within this Laguna.
The principal sources of stress on the Mexican side of the Laguna Madre are from overfishing. On the Texas side, the principal stresses are from nutrification and pollution, which come out of the Arroyo Colorado from agricultural, municipal, and shrimp aquacultural outflows. Direct and indirect target destruction on the Texas side arises from the dredging of the Intercoastal Waterway and from the use of ATVs on dunes and tidal flats.