CHAPTER IV: WILDLIFE HABITATS FOR MISSISSIPPI’S SGCN,

THREATS AND CONSERVATION ACTIONS^253

stuarine habitats include subtidal and intertidal areas. Subtidal habitats include the water column E

and benthic areas below extreme low water of spring tides. Texture of the substrate, salinity and water
depth are important parameters that distinguish subtidal habitats from one another. With the exception
of some of the barrier island lagoons, they have variable salinity levels. Estuarine areas that are partially
enclosed by the mainland include embayments, lakes and tidal streams. Barrier island ponds or lagoons
fit within this group. Over 300 Mississippi tidal creeks and riverine bayous cover approximately 5,500
acres. Coastal areas are also served by eight tidally influenced rivers that extend through estuarine
habitat for over 85 miles and cover an estimated 4,500 acres. The total surface area of Mississippi
Sound is approximately 500,000 acres; 25 percent is classified as nearshore habitat, less than two meters
(6.5 feet) deep and 75 percent as offshore habitat.

Salt, brackish and intermediate marshes and salt pannes account for most of the intertidal marsh habitat
of Mississippi, which totals almost 70,000 acres. Fire has been an important factor influencing the
vegetation of the marshes, estuarine shrublands and maritime flatwoods.

Areas that support or have supported seagrasses in the past are classified as seagrass beds. Seagrasses
are aquatic vascular plants that grow in shallow submerged estuarine waters. Non-vascular macroscopic
algae beds are a rare community included in this category. Seagrass beds are recognized as one of the
most important, diverse and productive communities of coastal waters.

This type includes seven subtypes: 14.1 Estuarine Bays, Lakes, and Tidal Streams, 14.2
Mississippi Sound, 14.3 Estuarine Marshes, 14.4 Barrier Island Passes, 14.5 Salt Pannes, 14.6
Seagrass Beds and 14.7 Mollusk Reefs.

GENERAL CONDITION

According to reports of the NOAA National Sea Grant College Program, "nearly half of the nation's
coastal wetlands have been lost, and wetland losses in some states exceed 90 percent”. Gulf coast states
possess the largest proportion of coastal wetlands remaining (17,000 square miles), yet these areas are
also disappearing rapidly due to coastal development. Beaches, dunes, seagrasses, coral reefs, oyster
reefs and other valuable habitats face significant pressures. Loss and deterioration of coastal habitats,
especially estuaries and wetlands, have dramatically affected U.S. fishery stocks. Landings of estuarine-
dependent fishes are down.

14. ESTUARY AND MISSISSIPPI SOUND

(INSIDE OR ASSOCIATED WITH BARRIER ISLANDS)