(freshwater intrusions) drive out or kill predators. Oysters 

 can withstand freshets by shutting their shells for long 

 periods . 



The oil industry has had two main effects on the oyster 

 populations of Louisiana, one direct and another indirect. 

 Oil pollution directly affects the commercial value of the 

 oyster. Oysters are sessile (attached to the substrate) 

 filter feeders. While feeding, they can ingest crude oil and 

 concentrate it in their systems. The ingestion of oil does 

 not affect their feeding process; however, an oily taste is 

 imparted, making them. undesirable in markets. Over time, 



if the oil is dispersed, the oysters will eventually 

 lose the oily taste. In a study done on the effects of an 

 oil spill from a Mecom Oil Company well, Mackin and Sparks 

 (1962) found that after 2 months, the oily taste had 

 "probably disappeared" from a great number of the population 

 in the most contaminated area (located in Grand Isle Block, 

 Freeport Sulphur vicinity ), because of the breakdown of the 

 oil. 



Salinity changes have been caused indirectly by the oil 

 industry through channeling and dredging for access to offshore 

 oil facilities. The increases in salt water allow the oyster 

 predators to enter oyster grounds and often cause serious 



106 



