Patrick J. Keniry

Run Timing, Spawn Timing, and Spawning Distribution of Hatchery- and Natural-Origin Spring Chinook Salmon in the Imnaha River, Oregon

Abstract We evaluated 16 years (1990–2005) of weir collection and spawning ground survey data to examine differences in run timing, spawn timing, and spawning distribution between naturally and hatchery-reared Chinook salmon Oncorhynchus tshawytscha in the Imnaha River, Oregon, and to look for changes in these variables over time. We compared run timing based on arrival time at the weir and found that naturally reared Chinook salmon arrived earlier than hatchery-reared fish in all 16 years. Carcasses of naturally reared fish of either or both sexes were recovered on the spawning grounds earlier than carcasses of hatchery-reared fish for all years combined and during 5 of 16 years, indicating earlier spawning by naturally reared fish. We compared spawning distribution using the percent of female carcasses recovered in each spawning ground survey reach. The percent recovery of the carcasses of naturally reared females was greater in reaches above the weir than below the weir and these carcasses were farther...

Migration Characteristics of Hatchery and Natural Spring Chinook Salmon Smolts from the Grande Ronde River Basin, Oregon, to Lower Granite Dam on the Snake River

Abstract Smolts of spring Chinook salmon Oncorhynchus tshawytscha experience substantial mortality while migrating through free-flowing reaches of the Snake River basin before reaching Lower Granite Dam, the first dam encountered in the Columbia-Snake river hydrosystem. We investigated the patterns of travel time and survival of hatchery and natural smolts fitted with passive integrated transponder (PIT) tags through specific reaches of the migration corridor during the 2000-2006 migration years for two populations originating in the Grande Ronde River basin (Lostine River and Catherine Creek). For both populations, median travel times for natural smolts were significantly longer in the upper reaches of the migration corridor but shorter in the lower reaches than for their hatchery counterparts. Also, among both hatchery and natural smolts, smaller individuals spent more time in the upper reaches, presumably feeding to attain a larger size before continuing their migration. Within populations, both hatche...

The Effect of Moderately Increased and Variable Raceway Flow Rates on Juvenile Physiology, Survival, and Adult Return of Hatchery-Reared Chinook Salmon

Abstract Increasing hatchery raceway flow to a rate similar to that seen in nature exercises salmon in the expectation that improving swimming ability will result in better survival. However, insufficient water prevents most hatcheries from fully simulating natural stream currents. We examined the effect of moderate and seasonally variable flow rates (0.25–0.75 body lengths/s) on growth and physiology of juvenile Chinook salmon Oncorhynchus tshawytscha and their ability to withstand acute stress, survive downstream migration, and return as adults. Changes in salmon growth, condition, and hematocrit followed similar patterns and did not substantially vary between treatments or cohorts. Patterns of change in plasma glucose levels were also similar for each treatment. Hepatosomatic index was higher in the 1994 cohort than in the 1995 cohort and in the exercised salmon. Liver glycogen levels were higher in the 1995 cohort. Plasma glucose and cortisol levels increased after stress and were greater in the contr...