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EFFECTS OF ALTERED HABITATS ON COMMERCIALLY IMPORTANT SPECIES OF THE NORTHERN GULF OF MEXICO
Impact/Purpose:
In any ecosystem, certain habitats are more essential than others for providing ecosystem services and functions. Understanding that it is impossible to manage every aspect of an ecosystem, EPA scientists and resource managers have agreed to concentrate efforts on these unique areas of the environment. The goal of Altered Habitat research is to establish quantitative models of the effects of altered habitats on the abundance and productivity of important aquatic species that can be used to support criteria for protection and restoration of critical habitats. Habitat-based criteria are of interest to EPAs Office of Water, and ultimately could be used by federal, state, and local agencies and permitting authorities for more uniform assessment and regulation of the quality and quantity of critical habitats.
Description:
This research emphasizes the role of critical estuarine habitats to species that provide an ecosystem service, namely those fish and shellfish of economic importance. Vegetated habitats are examined for their capacity to provide and sustain commercially important shrimp, oyster, crab and finfish populations. Each of these species exploits seagrass, marshes, or oyster beds for a particular life-support characteristic that is essential to their survival. Larval finfish, for example, might forage for particular sizes or types of invertebrate prey. Maintenance of oyster reef habitats might require intermittent infusions of freshwater to eliminate oyster predators and disease. Penaeid shrimp may use marshes and seagrass beds as refuge from predators and a source of food. Consequently, habitat must be evaluated not only on spatial extent, but on the extent of functional qualities, or attributes, for each species of interest. Our approach is stepwise: (1) characterize the dependence of commercially- and ecologically-important fish and shellfish on the extent and quality of coastal and estuarine habitats; (2) characterize coastal and estuarine habitats according to the attributes they provide each valued aquatic species; (3) link abundance and health of life-stages residing in critical habitats to the ultimate population success; (4) Estimate cumulative significance of habitat alterations, both qualitative and quantitative, to population success.