PROGRESS IN BIOLOGICAL INQUIRIES, lOST 55 



the various streams, the results were used as criteria for setting up 

 the initial stocking program. 



Other investigations in this area include studies of the food of 

 trout and other fish, collections of scales from brook, rainbow, and 

 brown trout to be used in a comprehensive study of the growth of both 

 wild and hatchery-reared trout in natural waters, and studies of the 

 survival of trout after planting and their adjustment to the new 

 environment, with special attention to the effect of winter conditions. 

 The Davidson River rearing station, constructed by the 1^'orest 

 Service, was operated very successfully. Sufficient trout of various 

 ages and species were produced to carry out the stocking program as 

 originally planned. Most of tlie fish Avere planted at 9 months of age 

 and were as large as the average wild fish in their second and third 

 years. While this growth rate cannot be expected to continue, these 

 fish have at least been started in their new surroundings with strong, 

 healthy bodies and a year's advantage in size. Specimens examined 

 2 to 3 months after jdanting were in excellent condition and compared 

 favorably with wild fish in the same stream. 



The Pisgah National Forest affords exceptional opportunities for 

 fish management studies, since all streams can be opened or closed to 

 fishing whenever desired and a complete check can be made of anglers'' 

 catches. The streams are patrolled regularly by Federal game ward- 

 ens and there is little poaching. 



Climatic and water conditions are also exceptionally favorable for 

 management studies. The district has one of the heaviest rainfalls in 

 the United States and partici])ation is normally regular throughout 

 the year. The comparatively short, mild winters allow a long grow- 

 ing season for fish and opportunities for studies of fish and fish food 

 organisms that are not possible in more northern sections. Among 

 the problems that are under investigation in this area is the extent to 

 which both brook and rainbow trout of various ages and sizes migrate 

 downstream when planted in the smaller and higher tributaries. The 

 results of these studies will have an important bearing on the advis- 

 ability of establishing so-called nursery streams that are closed to 

 fishing on the assumption that the trout on reaching a certain size 

 will descend to larger waters where they will be an important factor 

 in maintaining the supply of legal trout. 



Experiments are also under way to determine the stocking intensi- 

 ties of trout of various sizes that will produce most satisfactory re- 

 sults and the effect of various types of stream im])rovement on the 

 production of fish and bottom food organisms. In several streams only 

 marked trout of uniform size were planted so that it will be possible 

 to get reliable data on the growth and survival of these fish. 



Calffornia trout invest/' gat ion.'^. — The investigational program of 

 this unit was continued under the direction of Dr. P. R. Needham, 

 and good progress has resulted in spite of several changes in per- 

 sonnel and program. A. C. Taft resigned from the position of as- 

 sistant acjuatic biologist in January 19,37, to beconie Chief of the 

 Bureau of Fish Conservation of the California Division of Fish 

 and Game. This position was not filled for the remainder of the 

 fiscal year. As a consequence, tlie coastal stream steelhead investiga- 

 tions were turned over to the State Division of Fish and Game to 

 be contimied under the direction of that agency. Investigations at 



