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Author: Richard L. Townsend Publisher: ISBN: Category : Salmon Languages : en Pages : 67
Book Description
Since the 1994 outmigration, program RealTime has been applied to provide in-season predictions of smolt outmigration timing for individual and aggregates of listed threatened and endangered Snake River salmon stocks. Results from the 1997 smolt outmigrations of wild Snake River yearling and subyearling chinook show prediction of run-timing can be accurately forecasted. The number of release sites meeting previous years criteria for RealTime forecasts dropped to five for the wild spring/summer chinook parr PIT-tagged in 1996: Catherine Creek, Imnaha, Lostine, Minam and South Fork Salmon Rivers. An experiment in lessening previous RealTime requirements for forecasting a outmigration in progress added three release sites of chinook: Lake Creek, Secesh and South Fork Wenaha Rivers; and one release of age 1+ sockeye at Redfish Lake. Passage indices provided by the Fish Passage Center for Lower Granite Dam were monitored for the wild subyearling chinook outmigration. Investigation continued into basing predictions on historical years with similar flows as a way to improve forecasting performance for the wild subyearling outmigration. Program RealTime's output is a series of estimated percentages of the status of the smolt outmigration throughout the season. To compare the performance the program from year to year, or to compare various assumptions used set up the forecasting, the mean absolute deviance (MAD) of the daily predicted outmigration-proportion from the actual outmigration-proportion is calculated post-season. Furthermore, these MAD's are considered for three periods of the season: the first 50% of the season, the second 50%, and the entire season.
Author: Richard L. Townsend Publisher: ISBN: Category : Salmon Languages : en Pages : 67
Book Description
Since the 1994 outmigration, program RealTime has been applied to provide in-season predictions of smolt outmigration timing for individual and aggregates of listed threatened and endangered Snake River salmon stocks. Results from the 1997 smolt outmigrations of wild Snake River yearling and subyearling chinook show prediction of run-timing can be accurately forecasted. The number of release sites meeting previous years criteria for RealTime forecasts dropped to five for the wild spring/summer chinook parr PIT-tagged in 1996: Catherine Creek, Imnaha, Lostine, Minam and South Fork Salmon Rivers. An experiment in lessening previous RealTime requirements for forecasting a outmigration in progress added three release sites of chinook: Lake Creek, Secesh and South Fork Wenaha Rivers; and one release of age 1+ sockeye at Redfish Lake. Passage indices provided by the Fish Passage Center for Lower Granite Dam were monitored for the wild subyearling chinook outmigration. Investigation continued into basing predictions on historical years with similar flows as a way to improve forecasting performance for the wild subyearling outmigration. Program RealTime's output is a series of estimated percentages of the status of the smolt outmigration throughout the season. To compare the performance the program from year to year, or to compare various assumptions used set up the forecasting, the mean absolute deviance (MAD) of the daily predicted outmigration-proportion from the actual outmigration-proportion is calculated post-season. Furthermore, these MAD's are considered for three periods of the season: the first 50% of the season, the second 50%, and the entire season.
Author: Publisher: ISBN: Category : Languages : en Pages : 246
Book Description
In 2005, the University of Washington developed a new statistical model to analyze the combined juvenile and adult detection histories of PIT-tagged salmon migrating through the Federal Columbia River Power System (FCRPS). This model, implemented by software Program ROSTER (River-Ocean Survival and Transportation Effects Routine), has been used to estimate survival and transportation effects on large temporal and spatial scales for PIT-tagged hatchery spring and summer Chinook salmon and steelhead released in the Snake River Basin from 1996 to 2003. Those results are reported here. Annual estimates of the smolt-to-adult return ratio (SAR), juvenile inriver survival from Lower Granite to Bonneville, the ocean return probability from Bonneville to Bonneville, and adult upriver survival from Bonneville to Lower Granite are reported. Annual estimates of transport-inriver (T/I) ratios and differential post-Bonneville mortality (D) are reported on both a systemwide basis, incorporating all transport dams analyzed, and a dam-specific basis. Transportation effects are estimated only for dams where at least 5,000 tagged smolts were transported from a given upstream release group. Because few tagged hatchery steelhead were transported in these years, no transportation effects are estimated for steelhead. Performance measures include age-1-ocean adult returns for steelhead, but not for Chinook salmon. Annual estimates of SAR from Lower Granite back to Lower Granite averaged 0.71% with a standard error (SE) of 0.18% for spring Chinook salmon from the Snake River Basin for tagged groups released from 1996 through 2003, omitting age-1-ocean (jack) returns. For summer Chinook salmon from the Snake River Basin, the estimates of annual SAR averaged 1.15% (SE=0.31%). Only for the release years 1999 and 2000 did the Chinook SAR approach the target value of 2%, identified by the NPCC as the minimum SAR necessary for recovery. Annual estimates of SAR for hatchery steelhead from the Snake River Basin averaged 0.45% (SE=0.11%), including age-1-ocean returns, for release years 1996 through 2003. For release years when the ocean return probability from Bonneville back to Bonneville could be estimated (i.e., 1999 through 2003), it was estimated that on average approximately 86% of the total integrated mortality for nontransported, tagged hatchery spring and summer Chinook, and 74% for steelhead, occurred during the ocean life stage (i.e., from Bonneville to Bonneville). This suggests that additional monitoring and research efforts should include the ocean and estuary environment. Annual estimates of the systemwide T/I are weighted averages of the dam-specific T/I ratios for each transport dam (with e"5,000 tagged fish transported), weighted by the probabilities of being transported at each dam. The systemwide T/I compares the observed SAR under the existing transportation system with the expected SAR if the transportation system had not been operated. Estimates of 1.0 indicate that the systemwide transportation program has no effect on SAR, while estimates> 1.0 indicate that the transportation program increases SAR. Excluding the 2001 release group, the geometric mean of the systemwide T/I estimates for hatchery spring Chinook salmon from the Snake River Basin was 1.15 (SE=0.03) for release years 1997 through 2003. The geometric mean of the systemwide T/I estimates for hatchery summer Chinook salmon from the Snake River Basin was 1.28 (SE=0.13) for release years 1997 through 2000 and 2003. Estimates were much higher for the 2001 release groups. These estimates reflect transportation from Lower Granite and/or Little Goose for most release years, depending on the number of tagged smolts actually transported at each dam during each release year. Differential post-Bonneville mortality (D) is the ratio of post-Bonneville survival to Lower Granite Dam of transported fish to that of nontransported ('inriver') fish. Excluding the 2001 release year, the geometric mean of the D estimates for hatchery spring Chinook salmon from the Snake River Basin was 1.00 (SE=0.09) for release years 1997 through 2003. For hatchery summer Chinook salmon from the Snake River Basin, the geometric mean of the D estimates was 1.32 (SE=0.27) for release years 1997 through 2000 and 2003. These estimates reflect transportation from Lower Granite and/or Little Goose, depending on the number of tagged smolts actually transported at each dam during each release year. Approximately half the point estimates of D for both spring and summer Chinook salmon were 1.0 or greater, indicating that for those release groups, transported fish did not have lower ocean and adult survival than nontransported fish. For those years with estimates of D
Author: Publisher: ISBN: Category : Languages : en Pages : 88
Book Description
Program RealTime provided tracking and forecasting of the 1999 inseason outmigration via the internet for stocks of wild PIT-tagged spring/summer chinook salmon. These stocks were ESUs from sixteen release sites above Lower Granite dam, including Bear Valley Creek, Big Creek, Cape Horn Creek, Catherine Creek, Elk Creek, Herd Creek, Imnaha River, Lake Creek, Loon Creek, Lostine River, Marsh Creek, Minam River, South Fork Salmon River, and Secesh River, Sulfur Creek and Valley Creek. Forecasts were also provided for a stock of hatchery-reared PIT-tagged summer-run sockeye salmon from Redfish Lake and for the runs-at-large of Snake River wild yearling chinook salmon, and steelhead trout. The 1999 RealTime project began making forecasts for a new stock of PIT-tagged wild fall subyearling chinook salmon, as a substitute for forecasts of the wild run-at-large, discontinued June 6. Forecasts for the run-at-large were discontinued when a large release of unmarked hatchery fish into the Snake River made identification of wild fish impossible. The 1999 Program RealTime performance was comparable to its performance in previous years with respect to the run-at-large of yearling chinook salmon (whole season MAD=3.7%), and the run of hatchery-reared Redfish Lake sockeye salmon (whole season MAD=6.7%). Season-wide performance of program RealTime predictions for wild Snake River yearling chinook salmon ESUs improved in 1999, with mean MADs from the first half of the outmigrations down from 15.1% in 1998 to 4.5% in 1999. RealTime performance was somewhat worse for the run-at-large of steelhead trout in 1999, compared to 1998, particularly during the last half of the outmigration when the MAD increased from 2.7% in 1998 to 6.1% in 1999. A pattern of over-predictions was observed in half of the yearling chinook salmon ESUs and the steelhead run-at-large during the month of May. Lower-than-average outflows were observed at Lower Granite dam during the first half of May, the only period of low flows in an year with otherwise higher-than-average-flows. The passage distribution of the stock new to the RealTime forecasting project, the PIT tagged stock of fall subyearling chinook salmon, was predicted with very good accuracy (whole season MAD=4.7%), particularly during the last half of the outmigration (MAD=3.6%). The RealTime project reverted to a pre-1998 method of adjusting PIT-tagged smolt counts at Lower Granite Dam because of its superior performance during the last half of the outmigration.
Author: Publisher: ISBN: Category : Languages : en Pages : 122
Book Description
Program RealTime provided tracking and forecasting of the 2000 in season outmigration via the internet for stocks of wild PIT-tagged spring/summer chinook salmon. These stocks were ESUs from nineteen release sites above Lower Granite dam, including Bear Valley Creek, Big Creek, Camas Creek (new), Cape Horn Creek, Catherine Creek, Elk Creek, Herd Creek, Imnaha River, Johnson Creek (new), Lake Creek, Loon Creek, Lostine River, Marsh Creek, Minam River, East Fork Salmon River (new), South Fork Salmon River, Secesh River, Sulfur Creek and Valley Creek. Forecasts were also provided for two stocks of hatchery-reared PIT-tagged summer-run sockeye salmon, from Redfish Lake and Alturas Lake (new); for a subpopulation of the PIT-tagged wild Snake River fall subyearling chinook salmon; for all wild Snake River PIT-tagged spring/summer yearling chinook salmon (new) and steelhead trout (new)detected at Lower Granite Dam during the 2000 outmigration. The 2000 RealTime project began making forecasts for combined wild- and hatchery-reared runs-at-large of subyearling and yearling chinook, coho, and sockeye salmon, and steelhead trout migrating to Rock Island and McNary Dams on the mid-Columbia River and the mainstem Columbia River. Due to the new (in 1999-2000) Snake River basin hatchery protocol of releasing unmarked hatchery-reared fish, the RealTime forecasting project no longer makes run-timing forecasts for wild Snake River runs-at-large using FPC passage indices, as it has done for the previous three years (1997-1999). The season-wide measure of Program RealTime performance, the mean absolute difference (MAD) between in-season predictions and true (observed) passage percentiles, improved relative to previous years for nearly all stocks. The average season-wide MAD of all (nineteen) spring/summer yearling chinook salmon ESUs dropped from 5.7% in 1999 to 4.5% in 2000. The 2000 MAD for the hatchery-reared Redfish Lake sockeye salmon ESU was the lowest recorded, at 6.0%, down from 6.7% in 1999. The MAD for the PIT-tagged ESU of wild Snake River fall sub-yearling chinook salmon, after its second season of run-timing forecasting, was 4.7% in 2000 compared to 5.5% in 1999. The high accuracy of season-wide performance in 2000 was largely due to exceptional Program RealTime performance in the last half of the season. Passage predictions from fifteen of the sixteen spring/summer yearling chinook salmon ESUs available for comparison improved in 2000 compared to 1999. The last-half average MAD over all the yearling chinook salmon ESUs was 4.3% in 2000, compared to 6.5% in 1999. Program RealTime 2000 first-half forecasting performance was slightly worse than that of 1999 (MAD = 4.5%), but still comparable to previous years with a MAD equal to 5.1%. Three yearling chinook ESUs showed moderately large (> 10%) MADs. These stocks had larger-than-average recapture percentages in 2000, producing over-predictions early in the season, in a dynamic reminiscent of migration year 1998 (Burgess et al., 1999). The passage distribution of the new stock of hatchery-reared sockeye salmon from Alturas Lake was well-predicted by Program RealTime, based on only two years of historical data (whole-season MAD = 4.3%). The two new run-of-the-river PIT-tagged stocks of wild yearling chinook salmon and steelhead trout were predicted with very good accuracy (whole-season MADs were 4.8% for steelhead trout and 1.7% for yearling chinook salmon), particularly during the last half of the outmigration. First-half steelhead predictions were among the season's worst (MAD = 10.8%), with over-predictions attributable to the largest passage on record of wild PIT-tagged steelhead trout to Lower Granite Dam. The results of RealTime predictions of passage percentiles of combined wild and hatchery-reared salmonids to Rock Island and McNary were mixed. Some of these passage-indexed runs-at-large were predicted with exceptional accuracy (whole-season MADs for coho salmon outmigrating to Rock Island Dam and McNary Dam were, respectively, 0.58% and 1.24%; for yearling chinook to McNary, 0.59%) while others were not forecast well at all (first-half MADs of sockeye salmon migrating to Rock Island and McNary Dams, respectively, were 19.25% and 12.78%). The worst performances for these mid- and mainstem-Columbia River runs-at-large were probably due to large hatchery release disturbing the smoothly accumulating percentages of normal fish passage. The RealTime project used a stock-specific method of upwardly adjusting PIT-tagged smolt counts at Lower Granite Dam. For chinook and sockeye salmon, the project continued using the 1999 formulation for spill-adjustment. For the new stock of wild PIT-tagged steelhead trout, a formula derived for steelhead trout only was used.
Author: Publisher: ISBN: Category : Languages : en Pages : 67
Book Description
Since the 1994 outmigration, program RealTime has been applied to provide in-season predictions of smolt outmigration timing for individual and aggregates of listed threatened and endangered Snake River salmon stocks. Results from the 1997 smolt outmigrations of wild Snake River yearling and subyearling chinook show prediction of run-timing can be accurately forecasted. The number of release sites meeting previous years criteria for RealTime forecasts dropped to five for the wild spring/summer chinook parr PIT-tagged in 1996: Catherine Creek, Imnaha, Lostine, Minam and South Fork Salmon Rivers. An experiment in lessening previous RealTime requirements for forecasting a outmigration in progress added three release sites of chinook: Lake Creek, Secesh and South Fork Wenaha Rivers; and one release of age 1+ sockeye at Redfish Lake. Passage indices provided by the Fish Passage Center for Lower Granite Dam were monitored for the wild subyearling chinook outmigration. Investigation continued into basing predictions on historical years with similar flows as a way to improve forecasting performance for the wild subyearling outmigration. Program RealTime's output is a series of estimated percentages of the status of the smolt outmigration throughout the season. To compare the performance the program from year to year, or to compare various assumptions used set up the forecasting, the mean absolute deviance (MAD) of the daily predicted outmigration-proportion from the actual outmigration-proportion is calculated post-season. Furthermore, these MAD's are considered for three periods of the season: the first 50% of the season, the second 50%, and the entire season.
Author: Caitlin Burgess Publisher: ISBN: Category : Salmon Languages : en Pages : 151
Book Description
Program RealTime provided monitoring and forecasting of the 2003 inseason outmigrations via the internet for 33 PIT-tagged stocks of wild ESU chinook [sic] salmon and steelhead to Lower Granite and/or McNary dams, two PIT-tagged hatchery-reared ESU of sockeye salmon to Lower Granite Dam, and 15 passage-indexed runs-at-large, five each to Rock Island, McNary, and John Day Dams. All of the 23 stocks of wild yearling chinook salmon which were captured, PIT-tagged, and released at sites above Lower Granite Dam in 2002, have been monitored at least once before the 2003 migration. These stocks originate in drainages of the Salmon, Grande Ronde and Clearwater Rivers, all tributaries to the Snake River, and are subsequently detected to the tag identification and monitored at Lower Granite Dam. In a continuation from the previous two years, seven wild PIT-tagged runs-at-large of Snake or Upper Columbia River ESU salmon and steelhead were monitored at McNary Dam. Two wild PIT-tagged runs-at-large were monitored at Lower Granite Dam, the yearling and subyearling chinook salmon and the steelhead trout runs. The hatchery-reared PIT-tagged sockeye salmon stocks outmigrating to Lower Granite Dam consisted of a stock from Alturas Lake and one from Redfish Lake. The passage-indexed stocks (stocks monitored by FPC passage indices) included combined wild and hatchery runs-at-large of subyearling and yearling chinook, coho, and sockeye salmon, and steelhead trout forecasted to Rock Island, McNary, and John Day Dams.
Author: Publisher: ISBN: Category : Languages : en Pages : 88
Book Description
Program RealTime provided tracking and forecasting of the 1998 inseason outmigration via the internet for stocks of wild PIT-tagged spring/summer chinook. These stocks were from eight release sites above Lower Granite dam, including Bear Valley Creek, Catherine Creek, Elk Creek, Lake Creek, Imnaha River, Minam River, South Fork Salmon River, and Secesh River. Forecasts were also provided for a stock of hatchery-reared PIT-tagged summer-run sockeye from Redfish Lake and for the runs-at-large of Snake River wild yearling and subyearling chinook salmon, and steelhead. The 1998 Program RealTime performance was comparable to its performance in previous years for the whole-season evaluations for every stock tracked. Relative to 1997, performance improved for the yearling chinook run-at-large, and for predictions for last-half of the season for every other stock. Performance compared poorly with 1997 predictions for the first half of the runs of PIT-tagged yearling spring/summer chinook stocks and the run-at-large of fall subyearling chinook, and was slightly worse for the first half of the Redfish Lake sockeye run and the steelhead run-at-large. Poor first-half performance was likely due to the unusually large (and in some cases short) outmigrations in 1998. Utilization in 1998 of a different method of adjusting smolt counts at Lower Granite Dam compared to previous years produced slightly better first-half performance than pre-1998 adjustments would have, but slightly worse last-half performance, for all the PIT-tagged stocks, prompting a return to the pre-1998 adjustment formula for the 1999 outmigration. An Army Corp of Engineers (ACOE) experiment during April and May of 1998 involving the installation of two new components to existing structures at Lower Granite Dam did not appear to affect RealTime performance. A comparison of run-timing predictions based on FPC passage indices and Battelle hydroacoustic counts showed the two independent data sources produced very similar results, for the wild steelhead and yearling chinook runs-at-large. Due to the less than desirable first half performance in 1998, a refinement in the calibration process for Program RealTime will be conducted in the future.
Author: Caitlin Burgess Publisher: ISBN: Category : Salmon Languages : en Pages : 88
Book Description
Program RealTime provided tracking and forecasting of the 1999 inseason outmigration via the internet for stocks of wild PIT-tagged spring/summer chinook salmon. These stocks were ESUs from sixteen release sites above Lower Granite dam, including Bear Valley Creek, Big Creek, Cape Horn Creek, Catherine Creek, Elk Creek, Herd Creek, Imnaha River, Lake Creek, Loon Creek, Lostine River, Marsh Creek, Minam River, South Fork Salmon River, and Secesh River, Sulfur Creek and Valley Creek. Forecasts were also provided for a stock of hatchery-reared PIT-tagged summer-run sockeye salmon from Redfish Lake and for the runs-at-large of Snake River wild yearling chinook salmon, and steelhead trout. The 1999 RealTime project began making forecasts for a new stock of PIT-tagged wild fall subyearling chinook salmon, as a substitute for forecasts of the wild run-at-large, discontinued June 6. Forecasts for the run-at-large were discontinued when a large release of unmarked hatchery fish into the Snake River made identification of wild fish impossible. The 1999 Program RealTime performance was comparable to its performance in previous years with respect to the run-at-large of yearling chinook salmon (whole season MAD=3.7%), and the run of hatchery-reared Redfish Lake sockeye salmon (whole season MAD=6.7%). Season-wide performance of program RealTime predictions for wild Snake River yearling chinook salmon ESUs improved in 1999, with mean MADs from the first half of the outmigrations down from 15.1% in 1998 to 4.5% in 1999. RealTime performance was somewhat worse for the run-at-large of steelhead trout in 1999, compared to 1998, particularly during the last half of the outmigration when the MAD increased from 2.7% in 1998 to 6.1% in 1999. A pattern of over-predictions was observed in half of the yearling chinook salmon ESUs and the steelhead run-at-large during the month of May. Lower-than-average outflows were observed at Lower Granite dam during the first half of May, the only period of low flows in an year with otherwise higher-than-average-flows. The passage distribution of the stock new to the RealTime forecasting project, the PIT tagged stock of fall subyearling chinook salmon, was predicted with very good accuracy (whole season MAD=4.7%), particularly during the last half of the outmigration (MAD=3.6%). The RealTime project reverted to a pre-1998 method of adjusting PIT-tagged smolt counts at Lower Granite Dam because of its superior performance during the last half of the outmigration.
Author: Richard L. Townsend Publisher: ISBN: Category : Salmon Languages : en Pages : 67
Book Description
Since the 1994 outmigration, program RealTime has been applied to provide in-season predictions of smolt outmigration timing for individual and aggregates of listed threatened and endangered Snake River salmon stocks. Results from the 1997 smolt outmigrations of wild Snake River yearling and subyearling chinook show prediction of run-timing can be accurately forecasted. The number of release sites meeting previous years criteria for RealTime forecasts dropped to five for the wild spring/summer chinook parr PIT-tagged in 1996: Catherine Creek, Imnaha, Lostine, Minam and South Fork Salmon Rivers. An experiment in lessening previous RealTime requirements for forecasting a outmigration in progress added three release sites of chinook: Lake Creek, Secesh and South Fork Wenaha Rivers; and one release of age 1+ sockeye at Redfish Lake. Passage indices provided by the Fish Passage Center for Lower Granite Dam were monitored for the wild subyearling chinook outmigration. Investigation continued into basing predictions on historical years with similar flows as a way to improve forecasting performance for the wild subyearling outmigration. Program RealTime's output is a series of estimated percentages of the status of the smolt outmigration throughout the season. To compare the performance the program from year to year, or to compare various assumptions used set up the forecasting, the mean absolute deviance (MAD) of the daily predicted outmigration-proportion from the actual outmigration-proportion is calculated post-season. Furthermore, these MAD's are considered for three periods of the season: the first 50% of the season, the second 50%, and the entire season.
Author: Caitlin Burgess Publisher: ISBN: Category : Salmon Languages : en Pages : 122
Book Description
Program RealTime provided tracking and forecasting of the 2000 in season outmigration via the internet for stocks of wild PIT-tagged spring/summer chinook salmon. These stocks were ESUs from nineteen release sites above Lower Granite dam, including Bear Valley Creek, Big Creek, Camas Creek (new), Cape Horn Creek, Catherine Creek, Elk Creek, Herd Creek, Imnaha River, Johnson Creek (new), Lake Creek, Loon Creek, Lostine River, Marsh Creek, Minam River, East Fork Salmon River (new), South Fork Salmon River, Secesh River, Sulfur Creek and Valley Creek. Forecasts were also provided for two stocks of hatchery-reared PIT-tagged summer-run sockeye salmon, from Redfish Lake and Alturas Lake (new); for a subpopulation of the PIT-tagged wild Snake River fall subyearling chinook salmon; for all wild Snake River PIT-tagged spring/summer yearling chinook salmon (new) and steelhead trout (new)detected at Lower Granite Dam during the 2000 outmigration. The 2000 RealTime project began making forecasts for combined wild- and hatchery-reared runs-at-large of subyearling and yearling chinook, coho, and sockeye salmon, and steelhead trout migrating to Rock Island and McNary Dams on the mid-Columbia River and the mainstem Columbia River. Due to the new (in 1999-2000) Snake River basin hatchery protocol of releasing unmarked hatchery-reared fish, the RealTime forecasting project no longer makes run-timing forecasts for wild Snake River runs-at-large using FPC passage indices, as it has done for the previous three years (1997-1999). The season-wide measure of Program RealTime performance, the mean absolute difference (MAD) between in-season predictions and true (observed) passage percentiles, improved relative to previous years for nearly all stocks. The average season-wide MAD of all (nineteen) spring/summer yearling chinook salmon ESUs dropped from 5.7% in 1999 to 4.5% in 2000. The 2000 MAD for the hatchery-reared Redfish Lake sockeye salmon ESU was the lowest recorded, at 6.0%, down from 6.7% in 1999. The MAD for the PIT-tagged ESU of wild Snake River fall sub-yearling chinook salmon, after its second season of run-timing forecasting, was 4.7% in 2000 compared to 5.5% in 1999. The high accuracy of season-wide performance in 2000 was largely due to exceptional Program RealTime performance in the last half of the season. Passage predictions from fifteen of the sixteen spring/summer yearling chinook salmon ESUs available for comparison improved in 2000 compared to 1999. The last-half average MAD over all the yearling chinook salmon ESUs was 4.3% in 2000, compared to 6.5% in 1999. Program RealTime 2000 first-half forecasting performance was slightly worse than that of 1999 (MAD = 4.5%), but still comparable to previous years with a MAD equal to 5.1%. Three yearling chinook ESUs showed moderately large (> 10%) MADs. These stocks had larger-than-average recapture percentages in 2000, producing over-predictions early in the season, in a dynamic reminiscent of migration year 1998 (Burgess et al., 1999). The passage distribution of the new stock of hatchery-reared sockeye salmon from Alturas Lake was well-predicted by Program RealTime, based on only two years of historical data (whole-season MAD = 4.3%). The two new run-of-the-river PIT-tagged stocks of wild yearling chinook salmon and steelhead trout were predicted with very good accuracy (whole-season MADs were 4.8% for steelhead trout and 1.7% for yearling chinook salmon), particularly during the last half of the outmigration. First-half steelhead predictions were among the season's worst (MAD = 10.8%), with over-predictions attributable to the largest passage on record of wild PIT-tagged steelhead trout to Lower Granite Dam. The results of RealTime predictions of passage percentiles of combined wild and hatchery-reared salmonids to Rock Island and McNary were mixed. Some of these passage-indexed runs-at-large were predicted with exceptional accuracy (whole-season MADs for coho salmon outmigrating to Rock Island Dam and McNary Dam were, respectively, 0.58% and 1.24%; for yearling chinook to McNary, 0.59%) while others were not forecast well at all (first-half MADs of sockeye salmon migrating to Rock Island and McNary Dams, respectively, were 19.25% and 12.78%). The worst performances for these mid- and mainstem-Columbia River runs-at-large were probably due to large hatchery release disturbing the smoothly accumulating percentages of normal fish passage. The RealTime project used a stock-specific method of upwardly adjusting PIT-tagged smolt counts at Lower Granite Dam. For chinook and sockeye salmon, the project continued using the 1999 formulation for spill-adjustment. For the new stock of wild PIT-tagged steelhead trout, a formula derived for steelhead trout only was used.
Author: Richard L. Townsend
Author: Richard L. Townsend
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Author: Caitlin Burgess
Author: 
Author: Caitlin Burgess
Author: Richard L. Townsend
Author: Caitlin Burgess