World Status, Exploitation and Trade - WIDECAST

BURMATable 31. The numbers of turtles nesting and the eggs laid at DiamondIsland, taken from the records of the lessee of the egg collection rights(Maxwell, 1911). Although it is not stated, it appears that these figuresrepresent the number of eggs collected, rather that the total number laid.Year No of turtles No of eggs1883-8A*1884-85*1885-861886-871887-881888-891889-901890-911891-921892-931893-941896-971897-98118551578019993179261185916703171991207714143136991284712808137971406330185040023370002104500138930019308002011500143130016710001621200150910015117001668400Mean for complete years 14823 1744164* data incomplete, actual production estimated to be over two million eggsadult turtles should also be taken. Fortunately these recommendations werenot adopted, largely on the advice of the Financial Commisioner of Burma,and the closed season was retained. It is ironic that the DeputyCommissioner (Maxwell), arguing on the basis of albeit inadequate biologicaldata, should recommend relaxation of conservation measures, while theFinancial Commissioner intuitively held the converse view. History hasindicated that Maxwell was correct in his conclusion that the number of eggsspared was insufficient to replace the breeding stock as, by 1980, thenumber of eggs laid on Diamond Island had fallen by some 90%.A re-examination of Maxwell's data for the complete years' statistics(1885-1898) shows that the yield appears to have been declining over thatperiod. A regression line, fitted through the logarithmically transformedegg collection data, showed the yield to have declined by 2.37% a year(Correlation coefficient, r = 0.543, 9 d.f.). If this rate of decline isextrapolated forwards for the next hundred years, the predicted harvest in1977 would be 220 701 eggs. The fact that the actual recorded harvest wasso close to this value (225 815) is probably fortuitous, but it demonstratesgraphically that an apparently constant egg harvest of about 94% a year for100 years appears to result in a yield declining by an average of 2.4% ayear.The only other nesting site harvested in Burma which is predominantly ofC. mydas is South Moscos Island. Mustill (1939, cited in Salter, 1983)recorded that 60 000 eggs were harvested in 1939. The harvest had declinedto 21 000 by 1977 (see above), and it is interesting that this represents avery similar rate of population decline, around 2.7% a year.116