lives in the estuaries. Table 3.1 shows the migratory 

 behavior of selected coastal organisms. Fish are subjected 

 to two stresses from the oil industry: pollution from oil 

 spills and destruction of estuary nursery and feeding 

 grounds. Channeling and dredging have increased salinity 

 in most of the estuary and marsh areas of Louisiana. Changes 

 in salinity cause changes in flora, plankton, and overall 

 habitat. Levee building for drainage and flood protection 

 decreases the amount of freshwater runoff from land. This, 

 in turn, leads to a depletion in nutrients necessary for 

 plankton life (fish food). Straightening channels and 

 bayous increases the flushing rate and turbidity of the stream 

 or stops sheetwater flow, resulting in diminished wetland 

 nutrients. Increased turbidity affects ability of many 

 plankton species to float (Patrick, 1967). 



Fish populations can be damaged in five major ways by 

 oil spills'. 



Coating and exposure to hydrocarbon concentrations 

 in excess of 0.1 ppm cause eggs and larvae to die; 

 Adult fish, especially anadromous fish, die or 

 fail to reach spawning grounds if a spill occurs in 

 a critical, narrow, or shallow waterway; 

 Contaminated spawning of nursery grounds causes 

 loss of a local breeding population; 



92 



