70 



The region last named has been neglected almost entirely in the past ; during 

 the last 15 years only a small portion of the area has received any attention on thirteen 

 occasions, -while many square miles of sea bottom have been systematically ignored in 

 this region, which we have conclusive evidence to show formerly yielded fisheries. 



The Tolayiram Par deserves the Inspector's greatest attention ; it is the sole 

 region seen during the investigation suitable for cultural operations. The bottom 

 resembles the better parts of the Ceylon Oheval Par and like the latter premier bank 

 is the largest among its fellows in individual area. It has also a favourable record 

 for rearing its spat to maturity in great abundance. It may not receive so many spat 

 falls as the Karuwal group, but from its superior exteDt one successful fishery here, 

 is, if it be properly exploited by a sufficiency of divers, worth several of the smaller 

 Karuwal group fisheries. 



The Tolayiram Par should be mapped into blocks in the. way in which I have 

 mapped out the Ceylon Cheval Par (Annexure No. 8) and each of these should be 

 carefully studied, periodically inspected, and the results shown graphically in chart or 

 diagram form annually. 



Those parts of this region which came under my personal notice bore but small 

 quantities of loose stony material, " eultch " as it is technically termed, a decidedly 

 unfavourable factor, as the oysters need such material for the purpose of attachment. 

 Attention should in future be given to this detail during inspection, in order to ascer- 

 tain if this deficiency is, as 1 think it is, general over the whole area. In the event of 

 this proving to be case means should be taken to increase the available quantity 

 whenever an extensive spat fall is found to have occurred. 



Pearl Production — Causes op Death. 



Pearl production by the oysters fished in 18S9 on the Tolayiram Par, the only bank 

 regarding which I have any data, was less rapid than that noted during the past two 

 years on the Ceylon Cheval Par. On some sections of the latter satisfactory pearl 

 production is found at the age of four years, valued at over Ks. 21 per 1,000 in the 

 case of those fished in 1903, whereas the last oysters fished on the Tolayiram Par were 

 at a similar age valued at but Es. 3-11-5 per 1,000. It was not till they attained 

 the age of 5| years that they brought in an equivalent value (Rs, 22-B-6 being the 

 actual average price per 1,000 at the 1889 fishery) to that of Ceylon oysters 1| year 

 younger. The latter, however, were those from the richest known beds and there were 

 others which at the same age — 3| to 4 years — were not rich enough in pearls to give a 

 profitable fishery. Pearl production is, however, very variable and the yield by one 

 generation is not necessarily a criterion as to what the next may furnish, even upon 

 the same ground. 



Examination and comparison of the Tolayiram Par oysters of 18S7-90 with those 

 of Ceylon give fairly satisfactory results in respect to shell growth. They are not 

 equal to the finely grown oysters of the Cheval, but in general appearance are of a 

 healthy type. They are nowise stunted-looking as so many of the oysters on the Pars 

 more inshore are, or, as are the oysters characteristic of the Ceylon Muttuvaratu Par. 

 But although they are distinctly of the Cheval Par type, they are of slower growth and 

 the weight of the shells approximated closely to that of Muttuvaratu oysters. Given 

 an abundant infection of pearl-inducing cestode parasites, the pearl production should be 

 profitable in quality and quantity. This question is still one on which we are imper- 

 fectly informed ; the life-history of the parasite is still unsolved, and till we know the 

 animals which lodge the adult stage, we cannot formulate any plan for furthering the 

 increase in numbers of those of the larval stage, whose presence in the pearl oyster 

 controls the production of valuable pearls. 



The ratio of infection — and of consequent pearl production — varies greatly as is to 

 be expected consequent upon the local abundance or otherwise of the host of the adult 

 parasite whatever it may be, and also upon the relative profusion or scarcity of the 

 oysters themselves. 



Time after time I have proved by the dissection of large numbers of oysters of 

 the same age from different beds that the cestode infection may vary within consider- 

 able limits and as a consequence the pearl yield is proportionately variable. Tor 



