OYSTER CULTURE EXPERIMENTS IN LOUISIANA. 15 



It is evident, therefore, that the zone of water favorable for oyster 

 g^rowth. and especially for (he welfare of the spat, has moved <j;ener- 

 ally inland during recent years, owing to artificial changes in the 

 drainage system resulting from levee improvements. AVe have made 

 the same observations in Terrebonne Parish, Avhere oysters are es- 

 tablished in bayous which formerly carried water fresh at all times. 



The region nearer the coast is not so salt as of itself to inhibit the 

 growth of oysters, but it has become sufficiently so to be especially 

 favorable for the develoi)ment of a very destructive enemy of the 

 oyster, the snail or borer. Purpura., which kills the spat, though the 

 adults are innnune by reason of their heavy shells. On the other 

 hand, the more inland waters have Ijeconie sufficientl}' salt for the 

 oyster, but are still too fresh to furnish the environment required by 

 the borer. Of the two localities in which experiments were con- 

 ducted in Barataria Bay, Bay Tambour falls within the first region 

 and Bayou St. Denis in the second. In Bay Tambour, where natural 

 beds existed until exterminated a number of years ago by overfishing, 

 possibly supplemented b}- changes in salinity, the set on the experi- 

 mental beds was as heavy as at Bayou St. Denis, though the spat 

 were killed by borers Avithin a month or two. The adult oysters 

 were unharmed, and at Bayou St. Denis neither 3'oung nor adults 

 were molested and no borers were found. 



It is evident from the details of the experiments hereafter re- 

 counted that practically the entire bay may be utilized for oj^ster 

 culture wherever suitable bottom can be found or made. North of 

 a line running from the mouth of Bay Baptiste to about the mouth 

 of Bayou du Fone shells and other cultch may be planted with very 

 little risk of having the spat killed by borers and with every assur- 

 ance that a strike will occur each season. This part of the bay 

 covers about 8,000 to 10,000 acres. Though the bottom was not tested 

 over much of this area it is probable that a considerable part of it is 

 too soft for use without special preparation, though most of it Avill 

 doubtless be utilized eventually. 



South of the line above mentioned is a region, embracing the greater 

 part of the bay, where spat culture can not be attempted without 

 considerable risk or, usually, the certainty of meeting disaster through 

 (he depredations of the borer. In some localities the drumfish is 

 likely to prove destructive, but where this danger does not occur 

 oysters not less than U or 2 inches long can be planted with the 

 surety that they will grow into fine stock, commiinding a good ]irice 

 in the New Orleans market. 



Before the experiments were begim there was some objection to 

 the selection of Barataria as a field of operations, on the ground that 

 there was no industry at that place which could be benefited, and that 

 34455—10 3 



