22 



abundantly on sohk" of the natural reefs. Most of the speci- 

 mens found were small, and as they make only superficial bur- 

 i-ows in the shells of the oyster, they are of no particular im- 

 portance. In a later stage of its development this sponge forms 

 large orange colored masses, that nuiy entirely cover the oysters. 

 and interfere ^vith their feeding, but, as before stated, none of 

 the adult foj-ms were found. 



A boring clam, ]\Iar'Tesia ciuieiformis, is abundant in this- 

 i-egion. This clam when very small bores into the shell of the 

 oyster, and as the size of the clam increases, its burrow becomes 

 correspondingly enlarged. These burrows are found in th(^ 

 superficial layei's of the shell only and do no damage of im- 

 portance. 



The presence of algae and hydroids on the shells of oysters- 

 from some of the natural reefs acts as a detrimental agent by 

 collecting sediment and decreasing the amount of food material 

 that can be o])tained by the oyster. 



Among the oysters on some of the reefs mussels are present 

 in sufficient numbers to seriously interfere with the oysters. 

 Since the food of these forms is composed of the same kind of 

 plants, the amount available for each oyster is lowered by the 

 pi-esence of the mussels. 



By far the most formidable destructive agent to be encoun- 

 tered l)y one engaged in oyster culture in this region is the 

 annual spring freshet, which lowers the salinity of the water 

 in the bay and its tributaries during tlvfleedmg season of the 

 oyster. "While no authentic record of the freshets in years past 

 is availal)le, the best evidence obtainable shows that severe 

 freshets like that of the past year have been of infrequent occur- 

 rence. However, the increasing number of drainage canals 

 emptying into the head watei's of Vermilion Bay make it prob- 

 able that more damage from fresh water will occur in the future 

 than has l)een the case in past seasons. These canals offer a 

 means of escape for the water in the swamps which formerly 

 could reach the bay only after a slow passage through the small 

 branches of the bayous passing through the swampy area. The 

 large volumes of fresh water that can reach the bay through 



