EFFECTS OF HABITAT ALTERATION ON BLUE CRABS

Blue crabs, Callinectes sapidus, are an estuarine and coastal species subject to a wide range of environmental conditions. Their survival, g rowth, reproduction, and abundance are influenced by both natural proc esses and events and by human activities. How such activities might af fect the survival and abundance of blue crabs is the focus of this dis cussion. Because the life cycles and growth of blue crabs and other cr ustaceans are relatively complex, they are vulnerable to chemical and physical alterations to their habitat in different ways during their l ife. Not only are insults to the different life stages important, but negative impacts to the food webs that support them may also be damagi ng. When dealing with human-induced alterations to the environment, we often become preoccupied with the introduction of toxic chemicals and pesticides and their effects on individual organisms, and overlook le ss emotionally charged but more widespread threats, such as nutrient l oading, alterations of freshwater inflow, and physical destruction of estuarine and coastal habitat. Increasing human population densities a nd development near the Atlantic and Gulf of Mexico coasts may pose th e greatest threat to blue crab populations through alterations of upla nd watersheds with increased runoff, erosion, and turbidity, and incre ased nonpoint-source runoff of chemicals and nutrients. Unless these a ctivities are adequately controlled, the degradation of coastal habita t necessary for the survival and growth of blue crab populations will grow.