EARLY LIFE HISTORY OF SPRING CHINOOK IN OREGON'S GRANDE RONDE RIVER





        Life history diversity among salmon populations is becoming an


important concern for developing conservation plans and in the case of


endangered spring chinook of the Grande Ronde River, understanding life


history can assist in developing a recovery plan.  Conservation and recovery


plans such as Ecosystem Diagnosis and Treatment Model rely upon developing


a historical context for each native population.  It also develops recovery


actions that work with the strength of the salmon by making actions


consistent with the life history characteristics of each population.





        The Grande Ronde has six distinct wild spring chinook populations


and each is adapted to sprecific portions of the watershed.  The following


research notes the life history diversity among some of those populations.





Upper Grande Ronde River





        The spring chinook juveniles in the upper Grande Ronde have a


distinct fall and spring migration downstream.  The mid-October to late


November migration has fewer individuals, comprising 10 per cent or less of


the migrant population.





Catherine Creek





        The majority of the spring chinook juveniles migrate out of this


stream in the fall months from October to the end of December. The few that


leave this stream in the spring migrate in early March.





Arrival at Lower Granite Dam on the Snake River





        The Grande Ronde River is a tributary of the Snake River in Northeat


Oregon. The upper Grande Ronde River spring chinook arrive at this Snake


River dam from April to the end of July.  The fall migrant juvenile chinook


show up first at the dam, and two to three weeks separate the arrival of


fall and spring migrant chinook.  The fall migrant spring chinook abundance


at the dam is about twice that of the spring migrant fish.  Also, the fall


migrant spring chinook are significantly larger than the spring migrant fish.  





Mean daily growth rate





        The Catherine Creek spring chinook have a significantly faster


growth rate than the upper Grande Ronde fish, growing about .22 mm per day.


Most of this growth happens in the spring.  When these fish leave Catherine


Creek in the fall months they overwinter in the Grande Ronde in the valley


above the town of Elgin, Oregon.





        Pools are the preferred habitat in winter and summer for these


juvenile spring chinook.  However, the researchers have not been able to


locate key


overwinter habitat in the Grande Ronde above Elgin.  When water temperatures


drop during the late fall these fish are believed to enter the substrate of


the river and disappear.




















       This research, funded by the Bonneville Power Administration on


Columbia Basin wild salmon populations, was presented for review by


scientists at the Columbia Basind Fish and Wildlife Authority Project Review


held in Portland, Oregon on March 25, 1997.