TWENTY-NINTH BIENNIAL REPORT. 57 



where the eggs can be hatched and the resulting fish transported to a 

 point below the last dam or diversion in the Pit River. There are other 

 hydro-electric projects contemplated below Hagan Flat by other inter- 

 ests, that will have to be considered this coming season. If the obstruc- 

 tion at Redding is removed plans should be made without any further 

 delay to establish a salmon hatchery on the Pit River. Early next 

 season this matter should receive attention and action taken to the end 

 that whatever salmon ascend tlie river can be manipulated for their 

 eggs. Every salmon possible should be hatched and distributed in the 

 Sacramento and tributaries as there is less than 10 per cent of the 

 former breeding grounds of the salmon left. Salmon are decreasing 

 so rH]>i(lly that if enough salmon are to remain in our waters to supply 

 the local markets during a portion of the year, the chinook salmon must 

 be propagated to the fullest extent. 



BIOLOGICAL WORK. 



Under the supervision of Geo. A. Coleman, biological investigations 

 concerning our fresh water food and game fishes have been carried on 

 at Lake Tahoe, Clear Lake, Eel River Basin, Merced River Basin, Lake 

 Elsinore and other places where scientific prol^lems had to be worked 

 out to improve conditions of fish life. Plankton surveys have been made 

 looking toward the introduction of different species of fiishes into barren 

 lakes and the improvement of fish-planting work. 



This is a very important feature of the Avork of the Department of 

 Fish Culture and should be continued for a period of years until prac- 

 tical biological surveys of all the inland waters are complete, so that an 

 intelligent distribution of fish can be made. "While the department has 

 valuable data on many streams and lakes, there are miles of streams 

 and hundreds of lakes that should be given scientific investigation. 

 New problems are coming up that require special field investigation. 

 The long period of drought has changed the physical conditions of 

 many of our streams to such an extent that it is necessary to have special 

 investigations made to determine whether new species of fishes should 

 be introduced to meet the. changed conditions. The denuding of forests, 

 the construction of large reservoirs, breaking up the run of our native 

 species, the holding of the water in large reservoirs causing the tem- 

 perature to be higher than when the streams flowed unobstructed, and 

 many other conditions brought about by the use of water for the 

 development of the industries of the state have made it necessary that a 

 biologist connected with the Department of Fisl^ Culture be employed 

 to solve the problems that are continually arising. 



GENERAL CONDITIONS AND RECOMMENDATIONS. 



-Open Se(iso7i. Owing to the excessive fishing in all the lakes and 

 streams of California, it is necessary to find a new source of egg supply 

 to add to the rapidly diminishing supply of adult trout or spawners. 

 Several pond rearing systems for the raising of brood stock from which 

 eggs can be collected should be built as soon as funds are available. The 

 construction and maintenance of large rearing ponds is absolutely 

 necessary to furnish an adequate supply of eggs for the hatcheries. 



