Gulf Restoration Network

 

Destroying Their Homes: Loss and Degradation of Coastal and Marine Habitats

Over 50 percent of the Gulf region's wetlands have been lost since 1790. Furthermore, the Gulf ranked as one of the worst regions in the country for coastal water pollution and toxicity in a recent Environmental Protection Agency report. Coastal wetlands are extremely important to the majority of the Gulf's fish species due to the species' dependence on both estuarine and marine waters at some point in their life cycle. It is currently estimated that 95 percent of the commercially and recreationally important species in the Gulf of Mexico depend on both the waters of the open Gulf and the inshore and nearshore waters of the Gulf's numerous bays and estuaries. Some representative species include shrimp, red drum, and king mackerel.

Below are the major essential habitat types for Gulf marine life.  Click the habitat for a brief description.

Coral and Hard Bottom Communities

Coastal Marshes and Mangroves

Submerged Aquatic Vegetation

Non-vegetated Water Bottoms

 

Coral and Hard Bottom Communities

One of the most productive ecosystems on earth, coral reefs are an extremely important part of the Gulf of Mexico. These communities are critical to the Gulf's reef fish complex. In addition to coral reefs, other "hard bottom" areas include offshore "banks" and salt domes which are mounds providing area of relief along an otherwise flat bottom or relict reefs. These areas may contain some corals but do not possess the characteristics of coral reefs.

Shallow water reef in the Florida Keys

Location: coral reefs are mostly in the eastern Gulf of Mexico in the Florida keys, with isolated occurrences offshore of Texas. Corals need warm, clear waters in order to survive. Major coral areas in the Gulf include the Dry Tortugas portion of the larger Florida Keys reef tract the Florida Middle Grounds; Pulley Ridge; and the Flower Gardens National Marine Sanctuary. Hard bottom areas are found scattered throughout the Gulf of Mexico.

Threats: numerous, including damage from boat anchors, fishing gear, improper scuba diving practices, underwater pipelines, and polluted runoff from landbased activities.

Status in the Gulf of Mexico: Both the Flower Gardens and the Florida Middle Grounds have been designated "Habitat Areas of Particular Concern" (HAPCs) by the Gulf of Mexico Fishery Management Council. Designation of these areas as HAPCs prohibits many fishing practices which may damage corals. Portions of the Dry Tortugas were recently designated part of an ecological reserve. Little is known about deepwater corals in the Gulf of Mexico. The Sustainable Seas Expedition, a joint project of the National Geographic and the National Oceanic and Atmospheric Administration, explored some of these areas in the Gulf of Mexico in the summer of 2001.

 

Coastal Marshes and Mangroves

 Coastal vegetation, such as smooth cordgrass and mangroves, is a critical component of the Gulf's environment. These coastal plants provide needed shelter for young fish in the Gulf's estuaries. Considering that 95 percent of the commercially and recreationally important fish species in the Gulf of Mexico rely on the Gulf's bays and estuaries, it is critical that we protect these valuable areas. Location: Smooth cordgrass is the dominant vegetation along the land water interface in the Gulf region. Mangroves replace cordgrass in the warmer sections of the Gulf region such as South Florida and South Texas. 

 Status: The Gulf region has lost about 50 percent of its wetland resources. While difficult to quantify the extent of coastal wetland loss, figures do exist for coastal Louisiana (25-35 square miles lost per year) and Texas (about 1,800 acres lost per year). Furthermore, the population of the Gulf coast is expected to increase significantly over the next twenty years, placing great pressure on our wetland resources. For specific information on the state of the Gulf's wetlands, see our Wetlands Status and Trends page. The canal shown above cuts through existing smooth cordgrass marsh, resulting in habitat loss, and is now eroding the remaining marsh area. The majority of this area near Empire, LA has been changed from smooth cordgrass marsh to open water due to a number of factors.

 

Submerged Aquatic Vegetation (Seagrasses)

Submerged Aquatic Vegetation (SAV), including plants commonly referred to as seagrassess, serves as critical habitat for marine species in the Gulf of Mexico. This vegetation provides hiding places for young fish and marine life, as well as providing a food source for sea turtles, manatees, and waterfowl.

Location: SAV is found throughout the Gulf region in areas with suitable water quality. Most (98.5 percent) is found in the shallow bays and estuaries along the coasts of Texas and Florida. Florida is the only state with seagrass in the marine environment (in the open Gulf of Mexico).

Threats: SAV is particularly susceptible to poor water quality and physical disturbance. Increased nutrient loading and turbidity generated by dredging operations greatly impact SAV. In addition, propellers of boats create "scars" where boats pass over seagrass.

Status: While hard to quantify, seagrasses are believed to be decreasing in terms of abundance and diversity.

 

Non Vegetated Water Bottoms

The majority of essential fish habitat in the Gulf of Mexico is the relatively flat, non-vegetated portion of the continental shelf. Underestimated for its importance in biological productivity, these areas are now thought to be highly productive due to the benthic microalgae they support and the opportunities they present for burrowing species.

Location: The Gulf contains two primary non-vegetated flat bottom types: carbonate east of Alabama and terrignous west of Alabama to the Mexican border. The carbonate sediments of the eastern Gulf of Mexico, comprising quartz sand and carbonate sand (the fragmented remains of mollusks, sponges, corals, plankton, etc.), support a diverse assemblage of marine species. The terrigeneous sediments of the northern and western Gulf of Mexico, comprising sands, clays, and muds from the rivers in this region, provide a variety of different sediment types supporting a number of burrowing marine species.

Threats: Non-vegetated water bottoms are threatened by coastal development, water pollution, and, to varying degrees, fishing operations.

Status: Little is known about the state of non-vegetated bottom in the Gulf of Mexico. The current focus on the impacts that trawling gear has on benthic habitats may provide better information on the state of this essential fish habitat.