210 • SPOLTA ZEYLANICA. 



oyster beds are rendered barren , or whether they merely change their 

 diet. The scattered evidence on these points, which one discovers 

 only after much trouble in the published reports , is insufficient and 

 unconvincing. Doubtless Messrs. Hornell and Southwell obtained 

 an intimate knowledge of such details, but if they had put it on 

 record they would have saved their successors much trouble, and 

 the " legacy " which the Ceylon Company of Pearl Fishers left to 

 Government would have been incomparably richer. 



Mr. iSouthwell repeatedly states that the collection of data 

 regarding predatory fish has been carried on extensively and persis- 

 tentl3^ He says further : "Almost every fish caught has been 

 carefully examined in order to determine the nature of the stomach 



contents , and in this way thousands of fish have been 



repeatedly under observation."* Why was this information not 

 published ? It may make uninteresting reading, but it is the sort 

 of information to which future workers on the subject should have 

 the means of access. It is not sufficient to discuss the question in 

 a brief summary such as Mr. Southwell contributes in the Ceylon 

 Marine Biological Reports (Part IV., page 175). 



There is no ground for Dr. Jameson's supposition that Professor 

 Herdman and his successors have refrained from a campaign of 

 extermination of these predatory fishes on the ground that they pla}^ 

 an important part in the life cycle of the supposed pearl-inducing 

 parasite. As a point of academic interest, Herdman has drawn 

 attention to the fact that though an excess of predaceous fish would 

 destroy the oysters , the other extreme would be equally disastrous 

 from the point of i^earl production. But as a matter of practice no 

 mercy has been shown to those fish which have proved inimical to 

 the oysters. It is true that no active measures have been taken to 

 reduce the numbers of predatory fishes, but the reason of this is not 

 to be found in any desire to protect the fish because of their probable 

 importance in pearl production, but in the peculiar local conditions. 

 Apart from the trawling operations of the "Violet," which do not 

 extend over more than three months of the year, there is practically 

 no fishing pursued on the banks. The pearl banks happen to lie off 

 one of the most thinly populated parts of the Ceylon coast, and in 

 consequence there is practically no fishing industry of any import- 

 ance. If, for example, the banks had happened to lie off the coast 

 between Colombo and Galle, where sea fishing is practised extensively , 

 it would have been an easy matter to keep down the numbers of 

 predatory fish. In such a case, however, a rigid system of police 

 supervision would have to be enforced in order to prevent poaching 

 of pearls. 



The danger of overcrowding is one which has been fully recognized, 

 and the obvious remedy is to transplant some of the oysters to new 

 ground. Transplanting has not yet been carried out in a thorough 



* Ceylon Marine Biological Reports, 'Part IV., p. 177. 



