FORTY-FIRST BIENNIAL REPORT 83 



TEST WATERS 



Although much useful information can ho ohtaint'd fnuii cn-fl cen- 

 suses of the type previously described, it is usually ditlicult t(» contact 

 all anglers throughout the season and so obtain infoi-ination oj> total 

 yields from different lots of planted fish. Such inronuation niust be 

 obtained at "test" waters: streams and lakes where studies cau l)c made 

 under controlled conditions. 



The major test lake studied during th(> bienniuni was Caslle Lake 

 in Siskiyou County. A summary of results obtained there and at other 

 lakes in California will be published in a forthcoming issue of California 

 Fish and Game. 



Studies at Rush Creek Test Stream in Mono ( 'ounty and Sacramento 

 River Test Stream in Siskiyou County, initiated in 1!I47 and 1!»4S, 

 respectively, were continued during the bieuniiim. 



STREAM AND LAKE IMPROVEMENT 



FISH SCREENS 



The stream improvement heachiuai'ters at Vi-eka. Siski.Nou County, 

 continued as the center of fish screen activities conducted l)y the r.ureuu 

 of Fish Conservation. This has been supplemented by a small screen 

 maintenance shop in Weaverville. to service installations in Trinity 

 County. 



The Yreka shop installed screens maiidy in tiie Klamath and Trinity 

 drainages, but also constructed a feAV screens for use in other parts of 

 the State. 



Perhaps the outstanding achievement of the Yreka shop has been 

 the creation and development of a new type of fish screen known as 

 the "perforated plate screen." This type of screen is fully described 

 in an article in the October, 1950, issue of Califoniia Fish and iiamc. 

 It has now been thoroughly tested and is widely recognized as tli<' best 

 type which has ever been devised for irrigation diversions. Screens of 

 this type are now being installed in all diversions in r.ur»-au of Fish 

 Conservation District 1. 



An office building for use by the fish screen foi-eman and the hx-al 

 biologist was constructed at the Yreka headquarters during t he t.ienniuin. 



FISHWAYS 



Existing fishways in District 1 were maintained by pcrs<.nncl from 

 the Yreka headquarters and the AVeavervilie shop, and |)lans were <lrawn 

 for three new fishwavs which will be constructed in the near luture 

 Tests were made of fishway models of a new type, wIim-Ii may be usdul 

 at certain obstructions. Repairs and minor alterations were als.. .n;„Ie 

 to a few fishways by other pei'sonne! of the r.ureau. 



BARRIER REMOVAL 



The removal of abandoned dams to permit salmon and steeihea.l f. 

 reach important spawning areas has i)rogressed very satistactonly ... 

 tributaries of the Klamath and Trinity Rivers, with five dams removed 

 during the biennium. In addition, two log jam barriers wen- remoxd 

 from these tributaries. 



