20 



III. — The Possibilities of Oystkr culture on simple lines 



in Pulicat Lake. 



Excellent oysters exist in fair quantity and of good size in 

 the several localities in Pulicat Jake already particularized ; 

 under present conditions large stretches of suitable bottom in 

 shallow water are available for oyster culture by simple and 

 inexpensive methods and, were we reasonably sure that existing 

 favourable conditions will continue, no difficulties of impor- 

 tance would bar the way to very extensive cultural operations 

 and output. We have noted, however, in considerable detail 

 the occasional (periodic) extreme oscillations in level to which 

 the lake is subject — how at intervals of some five years the 

 shallows, which present conditions indicate as alone suitable for 

 oyster-culture, in great part dry by recession of the water-level. 

 No means are practicable to avert this periodic catastrophe. 

 Therefore if oyster- culture be attempted in Pulicat lake it must 

 be under limitations. Two plans are possible, which may be 

 tried either separately or simultaneously. The first is to limit 

 the culture to those places which we may reasonably assume 

 will never dry even in years of extreme drought ; the second 

 is to utilize the shallows, which dry up periodically, by arrang- 

 ing to plant them with brood oysters, as quickly as possible, 

 after one of the catastrophic years, and to harvest the crop 

 within the ensuing four normal years, which usually intervene 

 before the cyclic return of a year of exceptional drought shall 

 temporarily convert these shallows into dry land. 



This latter system of carrying on oyster-culture has the hall- 

 mark of Nature to attest its feasibility and its reasonableness. 

 The evidence is clear that when last the lake partially dried up 

 most of the oyster beds were left high and dry by the receding 

 waters with the consequence that the bulk of the oysters died 

 off from exposure to the sun and from lack of water. Very 

 few survived but these were sufficient to repopulate the beds 

 when the floods came to restore the lake to a normal level. 



It appears to me extremely probable that the spawning 

 season of Pulicat ovsters coincides with the onset of floods in 

 October and November. If so, at the end of a period of low 

 levels in the lake all the exposed old oyster shells will become 

 clean and bright by the combined action of sun and rain by the 

 time the)' are once more submerged by the rising waters and 

 will form the best possible kind of cultch for swimming oyster- 

 spat to settle upon. It will be remembered that I laid 

 emphasis upon the fact that with the exception of one deposit, 

 the oysters in each bed examined were of identical age through- 

 out that bed. There must be, at least, annual production of 



