250 The Philippine Journal of Science lou 



probably buried and smothered in the sand during a storm and 

 later uncovered by the currents or by a second storm. 



The Basilan beds were the scene of great activity during 

 July, 1914, a new bed, very rich in shells, having been discovered 

 during May, 1914. However, it is a well-known fact that the 

 Basilan shells are usually a little poorer in grade than shells 

 from other beds, a condition probably due to the very soft 

 bottom on which they grow. I have not yet been able to examine 

 either the Basilan or Mindanao beds. However, I examined 

 some valuable pearls taken from the Mindanao beds during 1914. 



After dredging on the various pearls beds, recording many 

 diving operations, and gathering information from numerous 

 divers and owners, I have concluded that the pearl beds of the 

 Department of Mindanao and Sulu are in no immediate danger 

 of exhaustion. It would be advisable to rest the Pilas and pos- 

 sibly the Pangutarang beds for three or four years. However, 

 I doubt if any regulation regarding the matter is necessary, 

 because the fishing does not pay expenses, and this will prevent 

 fishing more effectually than any law. 



The shallow-water beds in some cases have not been exhausted 

 after over one hundred years of fishing. The explanation of 

 this lies in the fact that they are constantly supplied with young 

 shells from the adjacent beds, "pockets," or mother shells, which 

 have been overlooked or lie in water too deep for the divers. 

 This I know to be the case in the Jolo beds, and no doubt it is 

 true of the others. All of the pearl beds are surrounded by 

 areas of deeper water, and many of the divers tell of seeing large 

 quantities of shells in waters too deep to work. These and the 

 overlooked pockets and scattered, adult shells are the "mother 

 shells," and from them are given off each season millions of 

 young pearl oysters, which are carried by the tides and currents 

 all over the waters of the Archipelago. Many settle on the 

 shallow beds and keep a constant supply of oysters growing 

 toward maturity. No doubt some are carried into great depths 

 and lost, others are smothered in the sand or thrown ashore and 

 die on the beach, but as each female oyster produces several 

 million eggs each year, many survive, and in this manner the 

 shallow-water beds are supplied continuously with shells. I be- 

 lieve that no amount of fishing with the present system of hand 

 pumps, whereby the diver is limited to a depth of about 25 fath- 

 oms, will ever fully exhaust these beds. Probably the greatest 

 danger to the Philippine pearl beds lies in the introduction of 

 motor-driven diving equipment that will enable the deep-water 

 beds to be fished. 



