is due to overfishing more than the effects of salinity 

 changes. Mackin and Hopkins (1962) define an oyster reef 

 as "an area of not less than 500 square yards of the bottom 

 of any body of water upon which oysters are found or have 

 been found within a term of five years... in quantitites which 

 would warrant taking them for profit by means of tongs." 

 The largest natural oyster reef in Louisiana is the Point au 

 Fer reef in the Atchafalaya Bay (Mackin and Hopkins, 1962). 



The first seed plantings were tried in 1886 near the 

 end of the Mississippi River delta with the Garden Island 

 Bay oyster culture. Plantings were later begun below 

 Quarantine Bay in an area known as the "Salt Works" (Mackin 

 and Hopkins, 1962). Natural reefs were used to provide seed 

 oysters. Oysters are dredged from the seed areas and trans- 

 ported to public and private leases for cultivation. Figure 

 3.2 shows the principal lease and seed grounds in southeast 

 Louisiana. 



Louisiana oysters tend to grow faster, spawn more 

 abundantly, and have a larger population in salinities up 

 to 30 ppt . The abundance of natural predators in higher 

 salinities forces the oyster to keep to lower salinity 

 waters. Mackin and Hopkins (1962) believe the best oyster 

 producing areas are high salinity waters where freshets 



104 



