ii CEYLON MARINE BIOLOGICAL REPORTS. 



nov.- out of print) were published whilst the banks were under the control of Government. All the 

 succeeding Reports represent a mere fraction of the work done by the Company. The Laboratory is 

 being closed on account of the fact that the leasing of tlie banks by the Company has not proved a 

 commercial success. 



I assume duties as Deputy Director of Fisheries for Bengal in December, 1911. 



2. — Causes which led to the Failttbe. 



It is impossible to give more than a brief outline of a few of the causes whicli led to the failure 

 Some of the factors are dealt with in Parts IV. and V. of the preceding Reports. 



The uncertain nature of the fisheries has been fully recognized for many centuries. Periods 

 of barrenness have always succeeded years of plenty, and the cause was never discovered. Steuart, 

 whose writings contain shrewd observations mixed with spicy romance, remarked in 1843 that the 

 intermittency of the fisheries was the act of God, and beyond the control of man. The investigations 

 conducted by Professor Herdman and by the Company had for their object, amongst other things, the 

 elucidation of this problem. How far the investigations have been successful will be gathered from 

 tUe Reports. 



As we have seen, the banks were leased out in 1905, and two successful fisheries resulted (1906 and 

 1907). Since then no fisheries have been held, and at the present time the banks are absolutely barren. 

 Even when spat is found, it will be four years before it can be fished, excluding the event of its bemg 

 lost in the meantime througli a variety of causes. The Company were granted the lease of the banks for 

 a period of twenty years, and were boxmd by the agreement to carry out the recommendations which 

 had already been made by Professor Herdman. The yearly rental to be paid was £20,000, and a further 

 smaller sum had to be expended in general scientific work. The working expenses were, of course, 

 additional. 



As the average profit on a normal fishery is about £60,000, it follows that in order to make the 

 enterprise successful a good fishery must take place within every three years. The history of the banks 

 abound with instances in which there are blanks of from four to fifty years, but in this connection it is to be 

 noted that up to six years ago only certain paars, such as the Cheval and the Muttuvaratu, were ever 

 inspected. Subsequent events have shown the high probability of oysters having occurred in times 

 past at other places close by these paars, as the entire plateau is potential paar ground. These question- 

 able blank years undoubtedly exaggerate the jjeriods of time when oysters were really absent. In view 

 of these facts the rental paid has been excessive, as liistory has shown. 



For the continuity of fisheries the isolation and protection of breeding stocks is essential. It 

 lias often been pointed out that even after a most thorough fishery there are bound to remain a few 

 scattered oysters which escape the vigilance of the divers. This is indeed so , but it has to be remembered 

 that the Ceylon pearl oysters have the sexes separate. They depend for their continuity on their seminal 

 products being wafted together by the movements of the water. Thus , although after a fishery thousands 

 of oj'sters are left scattered about here and there, it by no means follows that their seminal products 

 come together. A distance of even one yard 7nay be fatal. Thus, if the best results are to be obtained, 

 the necessity of leaving and protecting, say, ten compact beds of old oysters of about one acre in extent 

 becomes obvious. During normal fisheries anything from 40 to 80 million oysters may be fished, and 

 the number of oysters required to leave such compact and scattered beds would not be more than 1 to 

 2 million — an insignificant fraction of the whole. Since these facts were discovered there have been no 

 oysters on the banks, and thus the observation has as yet had no practical fruition. It was to protect 

 such beds as these, if found, that the Company purchased two years ago, at a cost of £3,500, wire 

 netting sufficient to protect an aggregate of one-sixth square mile of oysters. As the pearl banks cover 

 over 700 square miles, and as the cost of netting is prohibitive, to say nothing of the impossibility of 

 dealing on a large scale with netting, it is clear that it could not be used very extensively, and it was 

 never proposed to do more than protect breeding stocks to the extent indicated. Unfortmiately the 

 opportunity has never occurred. 



