51 



SPAWNING OF THE OYSTER IN TERREBONNE PARISH. 



Observations on the spawning of the oysters in these waters 

 were of necessity limited to the spring months. In the latter part 

 of March, 1907, when the beds in the western part of the parish 

 were visited, the oysters from all of tiie beds in shallow water 

 were "milky "—that is, with well-developed gonads. At the same 

 time those taken from the deeper parts of the channels in Bayou 

 Du Large and Bayou Grand Caillou, were fat, and the gonads 

 were just beginning to become noticeable. There were few spat 

 to be found on any of the shells taken up during the month of 

 March and the first half of April. From the evidence collected 

 during the two seasons in which these waters were visited it 

 seems that by far the greater part of the sexual products are 

 throAvn between the 15th of April and the 1st of July. The 

 spawning season seems to be some two weeks earlier in the 

 western part of the parish than in the eastern part, when bodies 

 of water of the same depth are compared. This may in part be 

 accounted for by the fact that in the bodies of water to the west- 

 ward the influence of the spring freshet is felt sooner than in 

 those farther to the east. In the same general region there are. 

 however, some very noticeable differences in the time of spawn- 

 ing that cannot be accounted for on the ground of changes in 

 the salinity of the water. In such cases it is probable that the 

 temperature has a great deal of influence, as the oysters in the 

 shallow water become "milky" before those from greater depth 

 where the temperature is lower. The weight of evidence seems 

 also to point to the fact that the oysters which have the most 

 abundant food supply ripen their sexual products earlier than 

 their less fortunate neighbore. These oysters would also cease 

 breeding before the others-and in the fall are the ones that first 

 become fat enough for market. 



ENEMIES OF THE OYSTER. 



The most destructive enemy with which oyster planters have 

 to contend in the waters of Terrebonne Parish is the drum fish, 

 or black drum (Pagonias cromis). This form does the most of 

 its damage to seed oysters or to bedded stock, and is of no great 

 damage to the natural reefs, except in that it sometimes destroys 



