Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Smolt Migration Characteristics And Mainstream Snake And Columbia River Detection Rates Of Pit Tagged Grande Ronde And Imnaha River Naturally Produced Spring Chinook Salmon PDF full book. Access full book title Smolt Migration Characteristics And Mainstream Snake And Columbia River Detection Rates Of Pit Tagged Grande Ronde And Imnaha River Naturally Produced Spring Chinook Salmon.
| Author | : Timothy R. Walters |
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| Release | : 1997 |
| Genre | : Chinook salmon |
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| Release | : 1996 |
| Genre | : Chinook salmon |
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| Total Pages | : 89 |
| Release | : 2000 |
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This reports details the 1998 study results from an ongoing project to monitor the migration behavior of wild spring/summer chinook salmon smolts in the Snake River Basin. The report also discusses trends observed in the cumulative data resulting from this project; data has been collected from Oregon and Idaho streams since 1989. The project was initiated after 3 years of detection data from PIT-tags (passive-integrated-transponder tags) had shown distinct differences in migration patterns between wild and hatchery fish. Data showing these patterns had originated from tagging and interrogation operations begun in 1988 to evaluate a smolt transportation program conducted by the National Marine Fisheries Service (NMFS) for the US Army Corps of Engineers. In 1991, the Bonneville Power Administration began a cooperative effort with NMFS to expand tagging and interrogation of wild fish for this project. Project goals were to characterize the outmigration timing of these fish, to determine whether consistent migration patterns would emerge, and to investigate the influence of environmental factors on the timing and distribution of these migrations. In 1992, the Oregon Department of Fish and Wildlife (ODFW) began an independent program of PIT tagging wild chinook salmon parr in the Grande Ronde and Imnaha River Basins in northeast Oregon. Since then, ODFW has reported all tagging, detection, and timing information on fish from these streams. However, with ODFW concurrence, NMFS will continue to report arrival timing of these fish at Lower Granite Dam. We continued to tag fish from Idaho in all years subsequent to 1992. Principal results from our tagging and interrogation efforts during 1997-1998 are given.
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| Total Pages | : 130 |
| Release | : 2001 |
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Program RealTime provided tracking and forecasting of the 2001 inseason outmigration via the internet for eighteen PIT-tagged stocks of wild salmon and steelhead to Lower Granite and/or McNary dams and eleven passage-indexed stocks to Rock Island, McNary, or John Day dams. Nine of the PIT-tagged stocks tracked this year were new to the project. Thirteen ESUs of wild subyearling and yearling chinook salmon and steelhead, and one ESU of hatchery-reared sockeye salmon were tracked and forecasted to Lower Granite Dam. Eight wild ESUs of subyearling and yearling chinook salmon, sockeye salmon and steelhead were tracked to McNary Dam for the first time this year. Wild PIT-tagged ESUs tracked to Lower Granite Dam included yearling spring/summer chinook salmon release-recovery stocks (from Bear Valley Creek, Catherine Creek, Herd Creek, Imnaha River, Johnson Creek, Lostine River, Minam River, South Fork Salmon River, Secesh River, and Valley Creek), PIT-tagged wild runs-at-large of yearling chinook salmon and steelhead, and a PIT-tagged stock of subyearling fall chinook salmon. The stock of hatchery-reared PIT-tagged summer-run sockeye salmon smolts outmigrating to Lower Granite Dam, consisted this year of a new stock of fish from Alturas Lake Creek, Redfish Lake Creek Trap and Sawtooth Trap. The passage-indexed stocks, counted using FPC passage indices, included combined wild- and hatchery-reared runs-at-large of subyearling and yearling chinook, coho, and sockeye salmon, and steelhead migrating to Rock Island and McNary dams, and, new this year, combined wild and hatchery subyearling chinook salmon to John Day Dam. Unusual run-timing and fish passage characteristics were observed in this low-flow, negligible-spill migration year. The period for the middle 80% of fish passage (i.e., progress from the 10th to the 90th percentiles) was unusually short for nine out of ten PIT-tagged yearling spring/summer chinook salmon stocks tracked to Lower Granite Dam. It was the shortest on record for seven of these ten stocks. The nine stocks recording unusually short middle 80% periods also recorded higher-than-average recovery percentages. However the opposite trend was observed for the PIT-tagged wild subyearling chinook salmon and hatchery sockeye salmon stocks whose middle 80% period of passage to Lower Granite Dam was average to above average. Recovery percentages for these two stocks were average, compared to historical recoveries. The performance results of Program RealTime to make accurate predictions of percentiles of fish passage at an index site were mixed this year. The release-recovery stocks of wild PIT-tagged spring/summer chinook salmon tracked to Lower Granite Dam were predicted less accurately than usual, on average, with two exceptions. One of these exceptions was a stock that had its best prediction (first-half, last-half, and season-wide) ever to occur. On average, however, performance was down for predicting these stocks. The RealTime Select composite season-wide MAD was 4.3%, larger than the historical average of 2.1%. Passage percentiles for PIT-tagged runs-at-large of wild Snake River yearling and subyearling chinook salmon and of wild steelhead outmigrating to Lower Granite Dam were predicted very well this year, their second year of inclusion in the project, with season-wide MADs of 3.6%, 4.7%, and 1.8% respectively. These results, too, were mixed with respect to comparison with last year's performance. The yearling chinook stock was predicted somewhat better last year (up from 1.7% last year to 3.6% this year) but the subyearling chinook salmon and steelhead stocks were predicted better this year than last, season-wide. The steelhead stock, in particular, was predicted much better this year than last year, down to 1.8% this year from 4.8% last year. The PIT-tagged runs-at-large of wild salmon and steelhead tracked to McNary Dam in 2001 for the first time, were also well-predicted. In particular, the Snake River stocks were well-predicted, with season-wide MADs of 4.7% for subyearling chinook salmon, 3.3% for yearling chinook salmon, and 1.4% for steelhead. All three Snake River stocks were better predicted at McNary Dam than they were at Lower Granite Dam. The Upper Columbia River PIT-tagged runs-at-large of wild subyearling chinook salmon and wild steelhead were not predicted with the remarkable accuracy of the Snake River stocks, but RealTime performance for these stocks was still good, with season-wide MADs of 7.9% and 4.9%, respectively. The results of RealTime predictions of FPC passage-indexed percentiles of combined wild and hatchery-reared salmonids to Rock Island and McNary dams were comparable to last year with respect to the large variability in performance. Like last year some runs were predicted very well while others were predicted very poorly. The stocks predicted best and worst last year were not necessarily the stocks predicted best and worst this year.
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| Total Pages | : 59 |
| Release | : 2009 |
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This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon O. nerka smolts during the 2003 spring out-migration at migrant traps on the Snake River and Salmon River. In 2003 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, these fish were distinguishable from wild fish by the occurrence of fin erosion. Total annual hatchery Chinook salmon catch at the Snake River trap was 2.1 times less in 2003 than in 2002. The wild Chinook catch was 1.1 times less than the previous year. Hatchery steelhead trout catch was 1.7 times less than in 2002. Wild steelhead trout catch was 2.1 times less than the previous year. The Snake River trap collected 579 age-0 Chinook salmon of unknown rearing. During 2003, the Snake River trap captured five hatchery and 13 wild/natural sockeye salmon and 36 coho salmon O. kisutch of unknown rearing. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. The significant differences in catch between 2003 and the previous year were due mainly to low flows during much of the trapping season and then very high flows at the end of the season, which terminated the trapping season 12 days earlier than in 2002. Trap operations began on March 9 and were terminated on May 27. The trap was out of operation for a total of zero days due to mechanical failure or debris. Hatchery Chinook salmon catch at the Salmon River trap was 16.8% less and wild Chinook salmon catch was 1.7 times greater than in 2002. The hatchery steelhead trout collection in 2003 was 5.6% less than in 2002. Wild steelhead trout collection was 19.2% less than the previous year. Trap operations began on March 9 and were terminated on May 24 due to high flows. There were zero days when the trap was out of operation due to high flow or debris. The decrease in hatchery Chinook catch in 2003 was partially due to differences in flow between years because there was a 5.9% increase in hatchery production in the Salmon River drainage in 2003. The decrease in hatchery steelhead catch may be partially due to a 13% decrease in hatchery production in the Salmon River drainage in 2003. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2003 data detected a relation between migration rate and discharge for wild Chinook salmon but was unable to detect a relation for hatchery Chinook. The inability to detect a migration rate discharge relation for hatchery Chinook was probably caused by age 0 fall Chinook being mixed in with the age 1 Chinook. Age 0 fall Chinook migrate much slower than age 1 Chinook, which would confuse the ability to detect the migration rate discharge relation. For wild Chinook salmon there was a 1.4-fold increase in migration rate, respectively, between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 1.7-fold and a 1.9-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2003 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for hatchery Chinook salmon, wild Chinook salmon and hatchery steelhead trout. Not enough data were available to perform the analysis for wild steelhead trout. Migration rate increased 14-fold for hatchery Chinook salmon, 8.3-fold for wild Chinook salmon and 2.4-fold for hatchery steelhead as discharge increased between 50 kcfs and 100 kcfs. Fish tagged with passive integrated transponder (PIT) tags at the Snake River and Salmon River traps were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental, and McNary dams). Because of the addition of the fourth interrogation site (Lower Monumental) in 1993 and the installation of the Removable Spillway Weir at Lower Granite Dam in 2001, caution must be used in comparing cumulative interrogation data. Cumulative interrogations at the four dams for fish marked at the Snake River trap were 65% for hatchery Chinook, 72% for wild Chinook, 66% for hatchery steelhead, and 67% for wild steelhead. Cumulative interrogations at the four dams for fish marked at the Salmon River trap were 48% for hatchery Chinook, 61% for wild Chinook salmon, 57% for hatchery steelhead trout, and 56% for wild steelhead trout.
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| Total Pages | : 70 |
| Release | : 2009 |
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This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon O. nerka smolts during the 2004 spring out-migration at migrant traps on the Snake River and Salmon River. In 2004 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, these fish were distinguishable from wild fish by the occurrence of fin erosion. Total annual hatchery Chinook salmon catch at the Snake River trap was 1.1 times greater in 2004 than in 2003. The wild Chinook catch was 1.1 times greater than the previous year. Hatchery steelhead trout catch was 1.2 times greater than in 2003. Wild steelhead trout catch was 1.6 times greater than the previous year. The Snake River trap collected 978 age-0 Chinook salmon of unknown rearing. During 2004, the Snake River trap captured 23 hatchery and 18 wild/natural sockeye salmon and 60 coho salmon O. kisutch of unknown rearing. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. Trap operations began on March 7 and were terminated on June 4. The trap was out of operation for a total of zero days due to mechanical failure or debris. Hatchery Chinook salmon catch at the Salmon River trap was 10.8% less and wild Chinook salmon catch was 19.0% less than in 2003. The hatchery steelhead trout collection in 2004 was 20.0% less and wild steelhead trout collection was 22.3% less than the previous year. Trap operations began on March 7 and were terminated on May 28 due to high flows. There were two days when the trap was taken out of service because wild Chinook catch was very low, hatchery Chinook catch was very high, and the weekly quota of PIT tagged hatchery Chinook had been met. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2004 data detected a relation between migration rate and discharge for wild Chinook salmon but was unable to detect a relation for hatchery Chinook. The inability to detect a migration rate discharge relation for hatchery Chinook salmon was caused by age-0 fall Chinook being mixed in with the age 1 Chinook. Age-0 fall Chinook migrate much slower than age-1 Chinook, which would confuse the ability to detect the migration rate discharge relation. When several groups, which consisted of significant numbers of age-0 Chinook salmon, were removed from the analysis a relation was detected. For hatchery and wild Chinook salmon there was a 2.8-fold and a 2.4-fold increase in migration rate, respectively, between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 2.3-fold and a 2.0-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2004 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for hatchery Chinook salmon, wild Chinook salmon and hatchery steelhead trout. Not enough data were available to perform the analysis for wild steelhead trout. Migration rate increased 7.0-fold for hatchery Chinook salmon, 4.7-fold for wild Chinook salmon and 3.8-fold for hatchery steelhead as discharge increased between 50 kcfs and 100 kcfs. Fish tagged with passive integrated transponder (PIT) tags at the Snake River and Salmon River traps were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental, and McNary dams). Because of the addition of the fourth interrogation site (Lower Monumental) in 1993 and the installation of the Removable Spillway Weir at Lower Granite Dam in 2001, caution must be used in comparing cumulative interrogation data. Cumulative interrogations at the four dams for fish marked at the Snake River trap were 82% for hatchery Chinook, 77% for wild Chinook, 90% for hatchery steelhead, and 90% for wild steelhead. Cumulative interrogations at the four dams for fish marked at the Salmon River trap were 68% for hatchery Chinook, 70% for wild Chinook salmon, 80% for hatchery steelhead trout, and 79% for wild steelhead trout.
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| Total Pages | : 62 |
| Release | : 2009 |
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This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon O. nerka smolts during the 2005 spring out-migration at migrant traps on the Snake River and Salmon River. In 2005 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, the age-1 and older fish were distinguishable from wild fish by the occurrence of fin erosion. Age-0 Chinook salmon are more difficult to distinguish between wild and non-adclipped hatchery fish and therefore classified as unknown rearing. The total annual hatchery spring/summer Chinook salmon catch at the Snake River trap was 0.34 times greater in 2005 than in 2004. The wild spring/summer Chinook catch was 0.34 times less than the previous year. Hatchery steelhead trout catch was 0.67 times less than in 2004. Wild steelhead trout catch was 0.72 times less than the previous year. The Snake River trap collected 1,152 age-0 Chinook salmon of unknown rearing. During 2005, the Snake River trap captured 219 hatchery and 44 wild/natural sockeye salmon and 110 coho salmon O. kisutch of unknown rearing. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. Trap operations began on March 6 and were terminated on June 3. The trap was out of operation for a total of one day due to heavy debris. FPC requested that the trap be restarted on June 15 through June 22 to collect and PIT tag age-0 Chinook salmon. Hatchery Chinook salmon catch at the Salmon River trap was 1.06 times greater and wild Chinook salmon catch was 1.26 times greater than in 2004. The hatchery steelhead trout collection in 2005 was 1.41 times greater and wild steelhead trout collection was 1.27 times greater than the previous year. Trap operations began on March 6 and were terminated on May 17 due to high flows. There were two days when the trap was taken out of service because of mechanical failure. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for passive integrated transponder (PIT) tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2005 data detected a relation between migration rate and discharge for hatchery Chinook but was unable to detect a relation for wild Chinook. The inability to detect a migration rate discharge relation for wild Chinook salmon was caused by a lack of data. For hatchery Chinook salmon there was a 1.8-fold increase in migration rate between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 2.2-fold and a 2.2-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2005 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for hatchery Chinook salmon, wild Chinook salmon, hatchery steelhead trout, and wild steelhead trout. Migration rate increased 4.2-fold for hatchery Chinook salmon, 2.9-fold for wild Chinook salmon and 2.5-fold for hatchery steelhead, and 1.7-fold for wild steelhead as discharge increased between 50 kcfs and 100 kcfs. Fish tagged with PIT tags at the Snake River and Salmon River traps were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental and McNary dams). Because of the addition of the fourth interrogation site (Lower Monumental) in 1993 and the installation of the Removable Spillway Weir at Lower Granite Dam in 2001, caution must be used in comparing cumulative interrogation data. Cumulative interrogations at the four dams for fish marked at the Snake River trap were 84% for hatchery Chinook, 89% for wild Chinook, 94% for hatchery steelhead, and 93% for wild steelhead. Cumulative interrogations at the four dams for fish marked at the Salmon River trap were 71% for hatchery Chinook, 78% for wild Chinook salmon, 80% for hatchery steelhead trout, and 81% for wild steelhead trout.
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| Release | : 2006 |
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| Total Pages | : 63 |
| Release | : 2009 |
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This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon smolts O. nerka during the 2002 spring out-migration at migrant traps on the Snake River and Salmon River. In 2002 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, these fish were distinguishable from wild fish by the occurrence of fin erosion. Total annual hatchery Chinook salmon catch at the Snake River trap was 11.4 times greater in 2002 than in 2001. The wild Chinook catch was 15.5 times greater than the previous year. Hatchery steelhead trout catch was 2.9 times greater than in 2001. Wild steelhead trout catch was 2.8 times greater than the previous year. The Snake River trap collected 3,996 age-0 Chinook salmon of unknown rearing. During 2002, the Snake River trap captured 69 hatchery and 235 wild/natural sockeye salmon and 114 hatchery coho salmon O. kisutch. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. The significant increase in catch in 2002 was due to a 3.1 fold increase in hatchery Chinook production and a more normal spring runoff. Trap operations began on March 10 and were terminated on June 7. The trap was out of operation for a total of four days due to mechanical failure or debris. Hatchery Chinook salmon catch at the Salmon River trap was 4.2 times greater and wild Chinook salmon catch was 2.4 times greater than in 2001. The hatchery steelhead trout collection in 2002 was 81% of the 2001 numbers. Wild steelhead trout collection in 2002 was 81% of the previous year's catch. Trap operations began on March 10 and were terminated on May 29 due to high flows. The trap was out of operation for four days due to high flow or debris. The increase in hatchery Chinook catch in 2002 was due to a 3.1 fold increase in hatchery production and differences in flow between years. Changes in hatchery and wild steelhead catch are probably due to differences in flow between years. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2002 data detected a relation between migration rate and discharge for hatchery and wild Chinook salmon. For hatchery and wild Chinook salmon there was a 4.7-fold and a 3.7-fold increase in migration rate, respectively, between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 1.8-fold and a 1.7-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2002 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for wild Chinook salmon and hatchery steelhead trout. The analysis was unable to detect a relation between migration rate and discharge for hatchery Chinook salmon. The lack of a detectable relation was probably a result of the migration rate data being spread over a very narrow range of discharge. Not enough data were available to perform the analysis for wild steelhead trout. Migration rate increased 4.3-fold for wild Chinook salmon and 2.2-fold for hatchery steelhead between 50 kcfs and 100 kcfs. Fish tagged with passive integrated transponder (PIT) tags at the Snake River trap were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental, and McNary dams). Because of the addition of the fourth interrogation site (Lower Monumental) in 1993 and the installation of the Removable Spillway Weir at Lower Granite Dam in 2000, caution must be used in comparing cumulative interrogation data. Cumulative interrogations at the four dams for fish marked at the Snake River trap were 61% for hatchery Chinook, 68% for wild Chinook, 58% for hatchery steelhead, and 62% for wild steelhead. Cumulative interrogations at the four dams for fish marked at the Salmon River trap were 51% for hatchery Chinook, 59% for wild Chinook salmon, 45% for hatchery steelhead trout, and 54% for wild steelhead trout. Cumulative interrogations were significantly lower in 2002 than in previous years with similar flow.
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| Total Pages | : 79 |
| Release | : 1991 |
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This project monitored the daily passage of chinook salmon Oncorhynchus tshawytscha and steelhead trout Oncorhynchus mvkiss smolts during the 1990 spring outmigration at migrant traps on the Snake River and the Clearwater River. Chinook salmon catch at the Snake River trap was similar to 1987 and 1988, drought years, but considerably less than 1989, a near normal flow year. Trapping effort was the same during the four years. Hatchery steelhead trout catch was similar to 1988 and 1989. Wild steelhead trout catch was greater than in any previous year. Chinook salmon catch at the Clearwater River trap was slightly less than in 1987 or 1988 and considerably higher than in 1989. Hatchery steelhead trout trap catch was 3 to 26 times greater than in previous years. Wild steelhead trout trap catch was 2 to 11 times greater than in previous years. Fish tagged with Passive Integrated Transponder (PIT) tags at the Snake River trap were recovered at the three dams with PIT tag detection systems (Lower Granite, Little Goose, and McNary dams). Cumulative recovery at the three dams for fish marked at the Snake River trap was 64.4% for chinook salmon, 83.1% for hatchery steelhead trout, and 79.0% for wild steelhead trout. Cumulative recovery at the three dams for fish PIT-tagged at the Clearwater River trap was 54.6% for chinook salmon, 77.6% for hatchery steelhead trout, and 70.4% for wild steelhead trout. Travel time (days) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged chinook salmon and steelhead trout, marked at the head of the reservoir, was affected by discharge. Statistical analysis showed that a two-fold increase in discharge increased migration rate by 2.2 times for PIT-tagged chinook salmon released from the Snake River trap and 1.8 times for chinook salmon released from the Clearwater River trap. A two-fold increase in discharge increased migration rate by 3.1 times for PIT-tagged hatchery steelhead trout released from the Snake River trap. Not enough data were available to provide a migration rate discharge relations for hatchery steelhead trout released from the Clearwater River trap. A two-fold increase in discharge increased migration rate by 2.0 times for PIT-tagged wild steelhead trout released from the Snake River trap and by 2.2 times for PIT-tagged wild steelhead trout released from the Clearwater River trap.
