TITK rK.MM. IMSIIF.niK.S OF CF.VI.ON. 489 



saftT locality furtlu'i- iiishoi-c. Mi-, lionicll was iiutliorizcd l»v llif 

 ^()\(M'ii()i' of (\'vloii (o ciiii-y out this rccoiniiKMidation, and went to the 

 IVriya Paar early in NovimiiIhm' with hoais and a|)|)lianc('s suitable 

 for the work, hut found he had aiiixcd too hi(e. 'I'he southwest mon- 

 soon had intervened, tlu' l)e(l had apparently heen swept clean, and 

 the enormous po])ulation of young- oysters, which we had seen in 

 March, and which might have been used to stock many of the smallei- 

 inshore paars, was now in all probability either buried in sand or car- 

 ried down the steep declivity into the deej) water outside. This expe- 

 rience, taken alono- with what we know of the })ast history of the bank 

 as revealed by the insj^ectors' rej)orts, shows that whenever young 

 oysters are found on the Periya Paar they ought, without delay, to be 

 dredged up in bidk and transplanted to suitable ground in the Cheval 

 district — the region where the most reliable paars ai'e placed. 



From this example of the Periya Paar it is clear that in considering 

 the vicissitudes of the pearl oyster banks we have to deal with great 

 natural causes which can not be removed, but which may to some 

 extent be avoided, and that consequently it is necessary to introduce 

 large measures of cultivation and regulation in order to increase the 

 adult population on the grounds, give greater constancy to the sup- 

 ply, and remove the disappointing fluctuations in the fishery. 



There are in addition, however, various minor causes of failure of 

 the fisheries, some of which we are able to investigate. The pearl 

 oyster has many enemies, such as star-fishes, boring sponges which 

 destroy the shell, boring mollusks which suck out the animal, internal 

 Protozoan and Vermean parasites and carnivorous fishes, all of which 

 cause some destruction and which may conspire on occasions to ruin 

 a bed and change the prospects of a fishery. But in connection with 

 such zoological enemies it is necessary to bear in mind that from the 

 fisheries point of view tiieir influence is not wholly evil, as some of 

 them are closely associated with peai'l production in the oyster. One 

 enemy (a Plectognathid fish) which doubtless devours many of the 

 oysters, at the same tiuie receives and passes on the parasite which 

 leads to the production of pearls in others. The loss of some individ- 

 uals is in that case a toll that we A-ery willingly pay, and no one would 

 advocate the extermination of that particular enemy. 



In fact, the oyster can probably coj^e well enough with its animate 

 environment if not too recklessly decimated at the fisheries, and if 

 man will only compensate to some extent for the damage he does bv 

 giving some attention to the breeding stock and " spat," and by trans- 

 planting when required the growing young from unsuitable ground 

 to known and reliable " paars.'' 



Those were the main considerations that impressed me during our 

 work on the banks, and, therefore, the leading points in the conclu- 



