88 COMMISSION OF CONSERVATION 



pleted, then swarming, and finally spatting. After that there are no eggs 

 or larvse left in the water, but there are the successful spat. Spatting 

 depends upon swarming and this upon spawning. Given the time of 

 spawning and the period of development, the time of spatting may be 

 calculated. Given swarmers (larvse) in any particular stage, size or age, 

 and the succeeding period of development and the time of spatting may be 

 calculated. Spatting is the all important event. The value of the oyster 

 harvest does not depend upon the number of eggs spawned, nor upon the num- 

 ber oflarvce in the water, but upon the number of successful spat. It is impos- 

 sibe to observe spatting directly, but it is possible, by close observation 

 of shells and other objects in the water to find some of the first deposited 

 minute spat, to approximate to the time when it begins. The information 

 however, may come too late for practical purposes. Hence the necessity 

 for relying upon earlier data. Spawning, like spatting, cannot be observed 

 directly, but, indirectly, it can be approximately fixed. The method is 

 laborious, the information limited and easily mistaken, and the time so far 

 antedates spatting as to leave room for accidents that can not be foreseen. 

 Swarming follows spawning and precedes spatting, so that information 

 gained from spawning can be followed up and subjected to verification 

 throughout the period of swarming to the very point when it is to be turned 

 to account in the capture of spat. 



After making use of all the methods, the information acquired holds 

 good only for the season to which the observations belong. Nevertheless 

 the events of one season point in a particular way to what may be ex- 

 pected in another season; to be forewarned is to be forearmed; and it is 

 important to limit these events, as far as possible, to particular dates 

 and periods of time. To do this with any degree of satisfaction, it would 

 be necessary to carry on a series of observations of these points through a 

 number of years. Hitherto my own observations have been confined to 

 two pretty fully utilized seasons and a small portion of each of two other 

 seasons. In the first season, that of 1904, the subject was not sufficiently 

 matured to permit of being made use of to the best advantage. In 1905 

 my observations were confined to the month of June. In the third 

 season, that of 1909, the necessity of moving from one place to another in 

 order to determine other points was a disadvantage so far as the present 

 subject is concerned. In 1911 my observations were on the Pacific coast. 



Date and Duration of Each Period. — Putting together what was rela- 

 tive to the subject on these different occasions it would appear that: 



Spawning is pretty likely to begin in the first week of July, rise through 

 the second week to its maximum in the third week, and then decline in the 

 fourth week. Continuous warm weather may bring it on in the last week 

 of June, persistent cold weather may hold it off until the third week of July. 



Swarming (swimming or larval stage) begins within a few days 

 after spawning, keeping parallel with and exhibiting like fluctuations. 



