118 COMMISSION OF CONSERVATION 



part of the time there is a mixture of all sizes, but a certain size may be 

 most abundant, as if constituting a distinct brood. There may be two or 

 three different distinct broods. Knowing the life-history and the approx- 

 imate period of growth it is possible to judge approximately when any 

 one brood will reach the stage of full-grown larvse ready to spat. For 

 greater assurance they may be followed from day to day right up to the 

 limit of larval growth. This is the time to put out cultch for that brood. 

 Cultch put out a few days before or a few days after may catch some spat 

 belonging either to that brood or to others, but it cannot catch so many. 



Necessity of Clean Cultch. — It is well known that cultch to be success- 

 ful in the catching of spat must be fresh and clean. After it has been in 

 the water for a time it becomes coated with slime, organisms and sediment, 

 to such an extent that the oyster larvae can find few or no spots upon 

 which they are able to fix themselves. Oyster shells form the most 

 readily accessible and very best cultch, but when put into the water they 

 become coated and largely lose their efficiency in even a few days. Hence 

 the necessity of holding the laboriously prepared, good, clean, white 

 oyster shells until a proper time arrives for planting them. If they are 

 placed at a wrong time and do not secure a set of spat, they have to be 

 again taken up and spread out to dry and bleach in the sun. which 

 kills the organisms and allows the slime and sediment to dry, 

 crumble and fall off in handling. There is not only the loss in time and 

 labour in re-cleansing the cultch, but there is the much greater loss of 

 the opportunity to secure the best catch of spat — perhaps a complete 

 loss for the season. 



Observation of success or failure over a long period of time has nar- 

 rowed down the practice of oyster culturists to certain situations, methods 

 and dates. The situations are natural oyster regions or such as can be 

 made oyster-producing. Of the methods, the procuring and planting 

 of natural seed and the management of cultch, are the most important. 

 The date for planting cultch, so far as is practised on the eastern coast of 

 the United States, is the latter part of June or first half of July. Some- 

 times planters strike a fortunate time, sometimes not. Even if they 

 count themselves lucky the chances are that they have been only partially 

 successful. The catch may be so small as to be scarcely worth the trouble. 

 There may be a complete failure to obtain seed . It has been stated that 

 in some years there has been no set of spat. 



Winslow in 1884 wrote: 



"Thousands of dollars would be annually saved by the Connecticut oystermen if 

 they could determine, with any approximate accuracy the date when the attachment 

 of the young oyster would occur. Hundreds of thousands would be saved if they had 

 any reliable method of determining the probabilities of the season." 



Determination of Time for Planting. — This is now possible. The 

 practices of oystermen are rules gained by experience and more or less 



