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CHAPTER IV: WILDLIFE HABITATS FOR MISSISSIPPI’S SGCN,

THREATS AND CONSERVATION ACTIONS^254

Issues affecting the coastal estuaries are the Gulf "Dead Zone;" the impacts of metropolitan sewage
outflows on coastal waters; and the causes and effects of toxic chemical contamination of oysters and
mussels. Furthermore, wetland losses are affecting the function of coastal ecosystems by contributing to
nutrient enrichment of coastal waters and the occurrence of harmful algal blooms, such as red and brown
tides.

Particularly on the mainland, pressure on coastal wetland habitats has dramatically increased over the
past 50 years. A significant percentage of coastal wetlands have been destroyed by filling and dredging.
By 1972, 12 percent of the intertidal marshes of Mississippi had been drained, filled or fragmented.
Regarding salt pannes, approximately 400 acres exist within the coastal estuary. The pannes, though
rarely found in Hancock and Harrison Counties, may have been more abundant in the past. In Jackson
County condition of the pannes appears to be stable. However, some losses of this habitat have occurred
due to an increase in seawater levels (or subsidence) and beach erosion.

Subtidal areas are affected by nutrients and pollutants that mainly enter the water from terrestrial
sources, especially urbanized areas. In some areas the pollution and nutrients from runoff and faulty
septic systems have increased significantly. In other areas, heavy metal and chemical releases from
industrial plants have been detrimental to aquatic species. Some bays, lakes and tidal streams are
enclosed and somewhat protected from wind and tides. These areas are more likely to become stagnant
during calm weather. The reduced mixing could lead to a segregation or increase in pollution gradient
creating hypoxia and fish kills. Hypoxic conditions can also occur in smaller areas because of oxygen
depletion and may also cause fish kills

Seagrass beds formerly covered an estimated 19,000 acres, but recent estimates indicate that only a
fraction of the original beds exist today. The extensive losses of seagrass beds is due to a variety of
causes, including hurricane damage, a decline in water quality and destruction of the beds by channel
maintenance, dredging, commercial fishery trawling, recreational fishing activities and even damage
from anchor dragging by recreational watercraft. Mollusk reefs are affected by salinity levels and water
quality. Pollution control within the coastal waters and watersheds of tributary streams is paramount to
the continuance of healthy and productive oyster reefs. Coastal environments provide some of the most
attractive living areas in the nation. It will continue to be a challenge to protect these areas for present
and future generations so that they may continue to enjoy the numerous benefits of a healthy wetland
ecosystem along the Mississippi coast. Over 90,000 acres of land have been designated by the
Mississippi Department of Marine Resources as coastal preserve habitat, much of which is tidal marsh,
creeks and lakes.