SPAWNING AND SETTING OF OLYMPIA OYSTERS 
441 
that the higher dikes are best for catching seeds while the lower grounds produce a 
superior product for market. 
METHOD OF CULTIVATION 
Although Galtsoff (1929) gave a description of the Olympia oyster industry and 
the methods of cultivation in use, it is necessary to review these matters briefly 
because of their bearing upon the experimental work which is described below\ After 
spawning is well under way in June the oyster growers plant cultch, either shells or 
manufactured collectors, on the seed grounds. Until about 1930 the only cultch 
available was the native shells from the opening houses, but with the recent plantings 
of Japanese oysters a great quantity of these large shells is obtainable (see fig. 1). The 
development of the concrete-coated egg crate filler has also made larger plantings of 
cultch possible (see fig. 2). The spat which are caught are generally left on the seed 
ground for about 3 jrnars before they are transplanted to growing grounds. Seeds 
are usually moved in April and May, permitting planting of new cultch on the same 
ground a short while later. Generally the seeds moved in spring are culled the follow- 
ing winter, though only the largest oysters reach market. 
All oysters are taken up by hand since the grounds are exposed when the tide is 
low (see fig. 3). At low tide on one day a place to set a scow is cleared by forking the 
oysters to either side. The scow is staked in position at high tide and, when the 
ground is again exposed, the oysters forked onto it. As soon as depth of water 
permits, the scow is towed to the culling house and the oysters unloaded into a “sink 
float”, made of two logs and a bottom, so that the oysters are washed free of mud as 
well as protected from weather conditions. They are taken up in wheel barrows from 
the sink float and loaded onto the large table in the culling house, where by tedious 
hand labor the marketable oysters are separated from the mass of shells and smaller 
seeds which are returned to the ground. The workers also separate the “slipper 
shells”, or “cups”, Crepidula jornicata, and the whelk or native snail, Thais lamellosa, 
and spread them high upon the beach to die and dry so they may be used as cultch. 
Cullers are paid extra for the snails and “cups” which they remove. 
The culled oysters are spread in another sink float where they are frequently 
forked over until the water washes them thoroughly clean. As recpiired for market 
they are packed in 2-bushel sacks and shipped to the opening houses. The cullers 
take up the oysters, return the seeds to the beds, and prepare the oysters for market 
and are paid on the basis of the number of sacks shipped. Japanese do almost all of 
this work as well as the shucking in the opening houses. 
The small size of the Olympia oysters, in proportion to that of the Eastern and 
Pacific (Japanese) species, renders them much more expensive to handle. The aver- 
age age of the marketable oyster is about 4 years, and about 5,000 of them are required 
to fill a 2-bushel sack. Ordinarily about 3 gallons of meats are obtained to the sack, 
so that a gallon contains about 1,600 oysters, as compared with 150 to 250 Easterns 
and about 50 to 200 Pacifies. 
ENEMIES OF THE OYSTER 
Although during the last few years there has been no apparent large mortality 
due to parasites, there are various organisms taking a constant toll of the crops. 
Ducks have given more trouble near Olympia than any other enemy (Galtsoff, 1929) 
and several species of these find the small size, single, native oysters an ideal, readily 
accessible food supply. Combating these is most difficult; and although some years 
