Inter-specif Ic crosses, the cross between domesticated hatchery 

 stock of speckled trout and natural stock of speckled trout, were cultured 

 at Dorlon hatchery and planted In Sheila Lake, a small barren lake In the 

 Geraldton District. The returns from these studies are not yet complete, 

 but the results are expected to provide Interesting and valuable data 

 relative to the growth and survival of the two strains of hatchery reared trout. 

 Lake and Stream Surveys 



The investigation of the physical, chemical smd biological condition 

 of lake and stream environments is the basis of all management. Such studies 

 are presently being conducted throughout the province as rapidly as possible. 



In general, the study includes a qualitative and quantitative 

 assessment of the habitat and the fish species contained therein. The investi- 

 gator usually considers such f eatures ,area and depth of the waters, the 

 shoreline, inlets and outlets, bottom types and aquatic vegetation. Water 

 temperatures and chemical analyses including oxygen and pH are determined at 

 various depths. The fish species, their condition and abundance, are usually 

 determined by a rather extensive netting program which may employ the use of 

 trap nets, gill nets and seine nets. 



Most of these studies are conducted during the summer months when 

 the investigator has the opportunity of working on open waters. However, 

 a few investigations are carried out during the winter particularly when fish 

 distribution and population studies are involved. 

 Tagging and Census Studies 



Growth rates, relative abundance and distribution of fish populations 

 are very significant requirements for the proper management of any fishery. 

 Such data are obtained in part from the results of survey investigations, 

 but unless the study is conducted specifically for this purpose a detailed 

 analysis is not always secured. Therefore, to augment this work and to 

 facilitate a more accurate and complete picture, sample fish are marked, either 

 by fin-clipping or tagging, and released for subsequent harvest. The return 

 of these fish, when recorded in detail, provides valuable data relative to 

 the status of the fishery. Such work is currently being conducted quite 

 extensively In nearly all the districts. 



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