STUDY NUMBER : 7.1 



ORGANIZATION ; Idaho Department of Fish and Game (IDFG) 



TITLE OF STUDY ; Lake Pend Oreille Fisheries Investigations 



CONTACT ( S ) ; Ned Horner - Regional Fishery Manager, Coeur- 

 d'Alene - (208) 765-3111 



OBJECTIVE ; Evaluate the suitability and contribution of Lake 

 Pend Oreille tributaries as spawning and rearing areas; monitor 

 the success of juvenile fish (fry) releases from the Cabinet 

 Gorge Fish Hatchery. 



DURATION ; 1982 - Indefinite 



CURRENT STATUS : During the past four years, inventories have 

 been conducted on the major spawning tributaries of Lake Pend 

 Oreille. The primary purpose of this research has been to collect 

 baseline information to better define fish management options. 

 Another benefit has been to ascertain the value of the tributaries 

 for perpetuating trout and char species within Lake Pend Oreille. 

 Major species of concern are bull trout, Gerrard rainbow and 

 westslope cutthroat trout. Population abundance and dynamics 

 were estimated for juvenile rainbow trout in tributaries to the 

 lake and data on the trophy fishery were complied to provide 

 a historical perspective for current enhancement goals. Fishing 

 effort in two major tributaries and harvest of juvenile adfluvial 

 rainbow was estimated to determine whether stream angling sig- 

 nificantly limits recruitment to the lake. Developing an estimate 

 of juvenile rainbow trout production from tributaries and doc- 

 umenting age at migration were objectives of graduate student 

 research begun in 1986. The IDFG now has important baseline 

 fisheries data so the impacts of land use and fishing pressure 

 can be monitored and if needed, regulated. 



Another portion of this study, initiated in 1985, is to 

 evaluate the success of kokanee fry releases from the Cabinet 

 Gorge Fish Hatchery. This hatchery was constructed to mitigate 

 losses to the once abundant kokanee from lake drawdown (Albeni 

 Falls Dam), loss of Clark Fork River spawning areas (Cabinet 

 Gorge Dam) and impacts from past introduction of Mysis shrimp. 

 The hatchery was cooperatively funded by the Bonneville Power 

 Administration, Washington Water Power Company, and Idaho Depart- 

 ment of Fish and Game. 



FUTURE ACTIVITIES : Graduate student research on production 

 of juvenile fish from tributary streams will continue in 1987. 

 Further quantification of wild trout and char production capa- 

 bility is needed to define future enhancement potential. 



Major emphasis will be placed on development of a fisheries 



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