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PEARL FISHERIES
has experimented with Roentgen rays for that purpose.
As the fish is enormously prolific it is more probable however that effort will be directed, instead toward the preservation of the mollusk from the enemies and accidents which are occasionally greater than its productiveness.
One of the greatest dangers in Indian waters to a bed of young oysters is a little mollusk known locally in Ceylon as suran (Modiola). These cluster in masses on the sea bottom and spreading over the surface of the coral, crowd out the delicate young of oysters recently deposited.
The Japanese fisheries suffer from the occa­sional infection of the waters by a weed, dinoflagellata gonyaulax. It accumulates in immense quantities, causing a wide discolora­tion of the sea water and is very destructive to an oyster-bed. It is called the red current or red tide. So far no preventive or remedy has been found.
Hitherto the most general and fatal danger to oyster-beds has been the ungoverned extrava­gance of irresponsible fishers who seek to harvest
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