PROGRESS IN BIOLOGICAL INQUIRIKS, 193 2 127 



and grown to inaturity in some bays. The seed of tlio last two species 

 is accompanied by other forms which become troublesome pests, but 

 with due precaution it is possible to cultivate these oysters safely in 

 isolated areas. 



The results of the investipition show that local conditions seem to 

 warrant the development of the native 03^ster industry to the fullest 

 extent. It is, however, imperative that the cultivation of oysters in 

 any one ba}' be limited to a single species as far as possible. Thus 

 the Japanese oj^ster can be grown on ground that is otherwise useless. 

 Eastern oysters can be planted in San Francisco, and Tomales Bays, 

 and Elkhorn Slough. In the latter locality seed oysters strung on 

 ropes and suspended from floats grow twice as fast as in their normal 

 habitat. 



Small beds of the native oyster occur in the larger bays of northern 

 California and in all bays and estuaries in southern California. They 

 have been of little commercial value prior to the present investigation 

 and the residents of the communities near the natural beds were 

 unaware of their existence. During the past year extensive experi- 

 ments have been undertaken, mostly in Humboldt Bay, and a method 

 of culture by the use of artificial beds has been worked out. Small 

 areas of barren tide flats in suitable locations are leveled, covered 

 with gravel or shell, and surrounded by a board w^ail wdiich holds 

 about 2 inches of water on the bed at low tide. Seed oj^sters and 

 shell are taken from the crow^ded natural reefs and transplanted to 

 these beds where the size, shape, and meat content is greatly improved . 

 It has also been demonstrated that the artificial beds catch a good 

 crop of seed, and it is therefore probable that nearly 7,000 acres of 

 tide lands in Humboldt Bay can be brought under mtensive culti- 

 vation. Native oysters have, heretofore, consistently sold for the 

 highest price of any oyster on the market, and the growers have 

 rarely been able to fill their orders completely. 



INVESTIGATIONS IN AQUICULTURE 



Investigations in fish culture and related problems were carried on 

 along much the same lines as in 1931. These investigations which 

 are under the direction of Dr. H. S. Davis necessarily cover a wide 

 field since they include studies relating to all phases of fish-cultural 

 activities. While the work in the past has been primarily concerned 

 with problems connected with hatchery operations increased attention 

 is now being paid to the welfare of the fish after being liberated. This 

 is fully as important as efficient methods of rearing fish since in order 

 to utilize these fish to best advantage they must be surrounded by 

 conditions conducive to their future development and well-being. 

 It is apparent that in many cases much can be done to improve con- 

 ditions in our lakes and streams so that they will be able to support 

 much larger numbers of fish than at present. This is a problem to 

 which relatively httle attention has been paid in America, although 

 in Great Britain and other European countries the importance of 

 stream conditioning has long been recognized and notable success has 

 attended its practical application, especially to trout streams. Stream 

 improvement is a field that offers great possibilities for the future, but 

 permanent progress must go hand in hand with years of painstaking 

 research. 



