24 OKHAMANDAL MARINE ZOOLOGY REPORT 



simple operation to plant numbers of stakes in the muddy bottom at the lower end 

 of the creek, or to lay out piles of suitably coated tiles at the spawning season 

 (yet to be ascertained) to form spat collectors ; the spat so collected, some months 

 later would be removed from the stakes or tiles and laid out on prepared (cleaned) 

 gravelly bottom and left there to mature, the bottom being carefully tended the 

 while to keep down seaweeds and destroy any enemies of the oyster. Variations 

 and improvements in details would evolve with experience. 



The initial experiments to prove that spat-collection and oyster-laying may be 

 successfully carried on should be conducted by Government. If satisfactory results 

 be obtained it is to be hoped that local people would then be induced to come forward 

 and take up sections of the creek on lease from the Government at a purely nominal 

 rental till such time as the industry may be established on a remunerative and stable 

 basis. After that it would be for the administration to decide whether the industry 

 could bear the payment of actual rent or whether it be more desii'able to be satisfied with 

 an indirect revenue return such as would accrue through the increased employment 

 provided and the greater prosperity induced in the district by the new industry. 



I may mention here that an extensive and profitable trade was carried on until 

 recently at Karachi in edible oysters obtained from the Sind coast. Some years ago it 

 was brought to the notice of the authorities that, owing to the improvident methods of 

 the oyster fishers, the oyster beds in Karachi and its vicinity were being rapidly 

 exhausted. To stay the progress of depletion and restore the prosperity of the beds 

 certain regulations were then adopted for the better control of the industry. These 

 protective measures appear to have proved unsuitable or insufficient, as the condition of 

 the beds is now (1908) in an unsatisfactory condition, the beds being practically 

 depleted. The rules which have thus failed in their object consisted in : 



(1) The observance of a close season from 16th April to 1st October in each year. 



(2) The licensing of fishermen engaged in collecting oysters for market. 



(3) Prohibition against the removal of oysters less than two inches or more than 



six inches in diameter. 



(4) Closure of the creeks by compartments to oyster-fishing in rotation for 



periods of two years. 



THE WINDOW-PANE OYSTER. 



This mollusc, Placuna placenta, provides a fishing industry of local importance 

 in four widely separated localities in eastern seas, to wit, Sind, Ceylon, Borneo and the 

 Dutch Indies. Pearls of inferior quality are yielded in some quantity, while the flat, 

 translucent shell itself is used in China and Indo-China and the Philippines as a 

 substitute for glass in the glazing of windows, whence the popular name. Formerly 



