St. Martins Marsh Aquatic Preserve was established on October 21, 1969. It includes 23,000 acres of submerged lands from the Crystal River to the Homosassa River in coastal Citrus County. It is composed of open water, mangrove islands, several inlet bays, tidal rivers and creeks, saltmarsh and adjoins upland hammock islands. Nutrient exchange between the marshes and the Gulf of Mexico makes the saltmarsh a significant area of primary production and a nursery ground for commercial and recreational fish species. The rivers contributing to the aquatic preserve drain over 1500 square miles. The marshes and coastal hammocks are a southern terminus for migratory waterfowl, providing wintering and stopover areas for these and other migratory bird species.