42 OYSTER CULTURE EXPERIMENTS IN LOUISIANA. 



The drumfish is reputed to cause some damage in these waters and 

 it is said that 5 per cent of the seed oysters planted are killed by it. 

 There were formerly several natural oyster beds, but they are now 

 wholly extinct, and it is stated that they have been unproductive for 

 about twenty years. It is believed that the extinction of these beds 

 is due largely to the great numbers of borers found in the lake. Dur- 

 ing the progress of the experiments hereafter recounted practically 

 all of the young oysters were killed by these industrious enemies, and 

 it may be fairly assumed that the same conditions obtained on the 

 original natural beds. With the majority of the spat being killed in 

 this manner and the adults being taken by the oystermen, the utter 

 extermination of the beds was practicall}^ inevitable. It is possible, 

 also, that the water has increased in salinity, and, therefore, has be- 

 come more favorable to the borers, through the improvement of the 

 levee system and the consequent changes in drainage. We have no 

 evidence that this is the case in the region under discussion, but it is 

 undoubtedly true in certain localities to the eastward already men- 

 tioned. The experiments in Pelican Lake were conducted on five 

 sites, three in the northern part of the bay and two in the southern 

 half. The characteristics of the several localities planted are as 

 follows : 



Bed A. — North of the mouth of California Pass. Bottom soft. 

 Currents moderately strong. 



Bed B. — West of the mouth of Bayou Go-to-Hell. Bottom moder- 

 ately hard. Currents strong. 



Bed C. — On the west side of the lake about halfway between the 

 preceding and Wilson Pass. Bottom moderately hard. Currents 

 not noted. 



Bed D. — East of the mouth of Wilson Pass. Bottom hard, on edge 

 of extinct reef. Currents of moderate strength. 



Bed E. — South of the mouth of California Pass. Bottom soft. 

 Currents moderate. 



On all of these the mud, as shown by mechanical tests with the 

 mud-sounding machine, was sufficiently firm to warrant planting 

 without previous preparation of the bottom. 



Planting of oyster shells spread broadcast were made on each of 

 these beds in May and June, 1907, and, in addition, on bed E in April, 

 1908, in quantities varying from 600 to 900 bushels per acre. No 

 experiments were made in planting seed oysters, as that method was 

 already under trial on a large commercial scale. 



On May 9, 1907, a single planting was made on bed B, and on June 

 30 every shell was found to bear spat about one-half inch long, while 

 on the same date sections of this bed and bed A, planted on May 27 

 and 29, had spat on from 25 to 45 per cent of the shells. Sections 

 on beds C and D, in the southern part of the lake, planted on the same 



