ARTIFICIAL OYSTER CULTIVATION. 1163 



between a few feet and perhaps thirty fathoms is so great, 

 that if you gave the oyster time to think about it, it would, 

 under these conditions, refuse to spat at all. But being 

 taken up in an advanced stage of pregnancy, it cannot 

 help itself, and rids itself of its burden as soon as it 

 can ; of course a much larger proportion of immature spat 

 is produced under these circumstances than under normal 

 conditions. 



Secondly, great care should be taken of the oyster 

 during removal, by protecting it from wind and consequent 

 evaporation whilst it is out of the water. When first 

 dredged up, oysters should be picked out of the accom- 

 panying rubbish, cleaned, and covered with sea-weed in a 

 cool place. No longer delay than can be avoided should 

 take place before they are relaid, and when they are out of 

 the water for more than twenty-four hours, sea-water should 

 be thrown over them occasionally. 



Deep-sea oysters spat most freely in shallow water, i.e. 

 in water of which the average depth at half ebb is from four 

 to six fathoms ; below this depth the difficulties of repro- 

 duction increase with the distance from the surface, and it 

 is doubtful whether spat is ever produced at a greater depth 

 than thirty fathoms, though of course it may drift and fall 

 there from shoaler water. The change, therefore, from 

 deep to shallow water should be accomplished gradually 

 (except in the one instance already mentioned), so as to 

 accustom the oysters to the new conditions. 



This gradual acclimatization should be carried out fur- 

 ther with oysters which have to be moved any distance. If 

 unaccustomed to be left uncovered at low water, they should 

 be raked or dredged in, and dropped first to a point between 

 low spring and low neap-water mark, and later on to above 

 the latter line, being moved a few feet further inshore every 



