64 
BULLETIN OF THE BUREAU OF FISHERIES 
May to August. April was not included in this because of the relative infrequency 
of the collections. The figure shows that the peak of spawning occurred in May and 
June, particularly the latter. The August collections at stations 4 and 5-6 in West 
Bay and station 3 in the bayou inlet contained somewhat more larvae than in July, 
indicating a possible acceleration of spawning at this time. 
Observations were brought to a close at the end of August, and it is not known how 
much longer spawning continued. From the records, however, it may be concluded 
that the spawning season was far from complete at this time. (See figs. 6, 7, and 8.) 
It may be assumed that the season continued for at least another month and possibly 
even longer. From the end of March until the end of August — a period of five months — 
spawning occurred apparently continuously, and it is reasonable to assume that the 
usual spawning period covers at least six months. During the time after spawning 
started only very occasional samples were taken which contained no larvse, and these 
were taken in stormy weather when the silt in the water clogged the net and rendered 
the collections of little significance. 
On the graphs showing daily abundance of larvse in the bayou (fig. 6) and at Deer 
Islands (fig. 7) the size range of the larvse taken is also indicated. Larvse in the straight- 
hinge stage are less than about 150 microns in length, while those 150 microns or 
more long are in the umbo stage. At about 200 microns length the larvae are close to 
the setting stage. Most larvse taken throughout the season were in the straight- 
hinge stage, and only at certain periods did umbo larvse appear. It would seem that 
the larvse either did not develop rapidly or else died before becoming mature, for the 
presence of large larvse in the water was closely associated with the appearance of 
spat. This is discussed more fully in the section on setting and need not be described 
further here. 
SEX OF OYSTERS 
While making examinations of oysters during the spring and summer, records 
were kept of the number of specimens of each sex. At irregular intervals small lots 
of unselected oysters were brought in from various reefs for the purpose of determining 
whether mature eggs were present in the gonads. The records showed, incidentally, a 
great predominance of females. Determinations made by Dr. Paul S. Galtsoff as 
well as those by the author are given in Table 1. In a few cases some specimens were 
either too completely spawned out or immature to permit ready determination of 
sex. In the table these are recorded as doubtful. Out of 252 oysters examined 178 
were females, 51 were males, and 23 were of doubtful sex. More than three times as 
many females were taken as males, although the samples were taken in small lots at 
different times from different places. In each lot examined, males were outnumbered 
by females. Even if all of the specimens considered doubtful were males there would 
still be more than twice as many females. 
It hardly seems possible that these results do not indicate the presence of more 
female than male oysters in this vicinity, although it has generally been found on the 
Atlantic coast that the two sexes are equally numerous. 
