130 



CEYLON PEARL OYSTER REPORT. 



transported than older ones, and more readily re-establish themselves on new 

 ground. 



The thinning out of overcrowded beds, sometimes a very necessary operation, can 

 be carried on concurrently with transplantation to a depleted area. For example, 

 in November, 1905, the dredging carried on amongst the overcrowded young oysters 

 of the Mid-east Cheval relieved pressure on that bed and at the same time provided 

 a stock for replenishing the denuded South Cheval Paar. 



As I have pointed out in a previous volume of this Report, it must be remembered 

 that the utility of dredging is by no means confined to the finding and fishing of adult 

 oysters, but is really manifold, and consists in the following, at least : 



(a) In exploring the ground ; 

 (6) In fishing oysters ; 



(c) In cleaning the ground and removing starfishes and other enemies ; 



(d) In thinning out overcrowded beds ; 



(e) In oyster transplantation. 



The value of dredging is not properly assessed if account be taken of only one of 

 these, such as fishing, or even of fishing and transplanting alone. Finally, it is 

 important to bear in mind that several of these useful operations can usually be 

 carried on simultaneously in the same series of dredgings. 



VIII. Other Marine Economic Work. 



In regard to the fish-trawling operations, I have to report that the greater part 



of Palk Bay presents a large open expanse with a 

 uniform soft bottom suitable for trawling. Our hauls 

 in both the northern and the southern parts of 

 the area showed that there are plenty of fish, and 

 apparently this shallow sea serves as a very valuable 

 nursery for young sea-fish. We also found off Galle, 

 to the east of the Gallehogalle Bank, at a depth of 

 L!5 to 30 fathoms, an area which may be regarded 

 as a fish-nursery. Here it is evident that the young 

 of both flat and round fish, belonging to about ten 

 species and including such valuable forms as may be 

 called "Soles," " Turbot," and "Plaice" (although 

 not the same species as those in home seas), congregate 

 in large numbers. 



It will naturally be part of the duty of the Marine 

 Biologist to the Colony to make himself acquainted 

 with the conditions of the native fisheries, and be 

 prepared to advise as to whether facilities should be given for introducing trawling 



Fig. 17. The commercial sponge 

 (Eu.yongia officinalis, var. ceylon- 

 ii-n) from Trincomalee, as seen 

 when alive ; reduced in size. 



