184 DESCRIPTION OF IMPORTANT FISHERIES AND THEIR PRODUCTS 



and trial plantings made on Willapa Bay and on Puget Sound. These 

 experimental plantings showed such promise that the efforts were con- 

 tinued and C. gigas, now known as the Pacific oyster, is now the basis 

 of the West Coast industry. 



The oyster is a bivalve mollusc, that is having two shells as do the 

 clams and scallops. The sexes may be separate or may alternate within 

 the same individual depending upon the species. At first a free swimming 

 organism, the young soon settle to the bottom where they attach to any 

 hard object. This characteristic, and the fact that the oyster grows in 

 shallow protected areas, has made it possible to raise oysters as a crop 

 and has been an important factor in saving the industry from extinction. 



Harvesting. Oysters may be harvested by three methods: (1) by 

 gathering by hand when the tide is low, (2) by ''tonging," and (3) by the 

 use of power dredges when the beds are flooded. Hand gathering or 

 ''picking" was, of course, the means employed by primitive man and 

 was used up to the inception of the industry. This method of harvesting 

 had the disadvantage that it could only be used for brief daily intervals 

 when the beds were exposed at low tide. With primitive peoples this 

 was not important. As commercial use of the beds increased, however, 

 more efficient means were needed, especially a means of harvesting when 

 the beds were flooded. Thus "tonging" came into use. Oyster tongs are 

 a device similar to two rakes hinged together near the lower ends and 

 with the rake-like teeth facing each other. A man standing on the deck 

 of a boat or bateau floating over the beds can, by lowering the tongs to 

 the bottom and by opening and closing the handles, scoop up a quantity 

 of oysters between the rake-like heads. Tonging, like hand picking, is slow 

 and has largely given way to power dredging. The dredge may be a 

 power-driven boat or a barge. The dredge tows a ''drag," a metal frame 

 having a toothed bar across the front. This toothed bar dislodges the 

 oysters from the sand and mud and they roll back across the drag bar 

 into a chain mesh bag that collects and holds the oysters until the drag 

 is lifted and the contents dumped onto the deck of the dredge boat. 

 Power dredging is the most economical method of harvesting oysters 

 and now accounts for two-thirds of the oysters harvested. 



Processing. Oysters are prepared for market in various ways. The 

 larger plants employ large scale conveyor equipment to move the oysters 

 through the plants Thus, travelling crane hoists may be employed to 

 carry shell stock to bins over the shucking tables. 



If the oysters are to be marketed as shell stock, that is unopened, only 

 washing of the shells, packing in sacks or barrels, and chilling are required. 

 Prior to shipment, the oysters may be kept in chlorinated water for a 

 time to eliminate undesirable bacteria. Oysters are marketed in this 



