FISHERY RESOURCES OF THE PHILIPPINE ISLANDS. 91 



very abundant. Such a bank was found just south of Basilan Island; 

 another near the Tapu Islands, and another in Tataan Pass of Tawi-Tawi 

 Island. A large yield of shell has been secured near the Samales group. 

 Shell has been reported from lUana Bay, and during the past year an 

 extremely valuable bank was_ located in the Gulf of Davao in Pakiputan 

 Strait between Samal Island and the mainland. The most prolific por- 

 tion of the bank was in the narrow part of the passage directly between 

 Point Lanang and Point Linao. The depth of water is from 20 to 25 

 fathoms. The bank is well protected above by the large reef known as 

 Arboles Island. Usually, there is a very strong current pouring through 

 this strait, but at the point where the pearl bank occurs the tides and 

 currents form a strong eddy which has doubtless contributed to the 

 formation of the bank by giving an opportunity for the spat to settle and 

 attach. The bottom is of coral, sand, and gravel, and is comparatively 

 smooth. The width of the strait at this place is less than 1.6 Irilometer 

 (1 mile) ; the beach on one side slopes steeply down, and on the other 

 drops abruptly into several fathoms of water from a live coral reef. The 

 water is quite clear, its "temperature about .24° C, and its specific gravity 

 1.022. At the time of my visit (May, 1908), there were only four 

 pearling boats operating on this bank; two others were prospecting in 

 adjacent waters. 



The currents were so swift that diving could be carried on only between 

 the hours of 6 and 7 o'clock in the morning. The diver, a Filipino, 

 during this hour made three trips to the bottom; on the first he secirred 

 .three shells; on the second, eight; and on the third, two. These were 

 all large, first-class shells, each weighing about 3.2 kilos (7 pounds). 

 One contained a small pearl. 



The diver brought up some young shells for our inspection, and reported 

 that they were abundant on the bed. All the large oysters were in a 

 breeding condition, so probably this bank will be able to keep up a 

 moderate jielA, unless overfished at the beginning. So far, the Davao 

 pearl bank has yielded about 56 tons of first-class shell. 



Pearl shells in considerable numbers are found in Taiion Strait, between 

 Cebu and ISTegros Islands; in the vicinity of Guimaras; and also along 

 the west and the north coast of Samar. Shell has also been reported 

 from Palawan and Cagayan Sulu. It is more probable that as the 

 Islands become better known, many new pearling banks will be found, 

 and those now known will be mapped and better defined. 



The most desirable bottom for a pearl bank is coarse sand, with dead 

 coral and rock to whicli the young may attach. They can not grow on 

 live coral, and they are very apt to be covered up and smothered on fine 

 sand. 



