Bill Kiene semi-retired
12-19-2011, 08:55 PM
Fishing Report Week of December 19, 2011
The American River flows remain stable at about 2,200 cfs, water temperatures about 52o F and clear. Weather is stable and sunny with daily highs in the high 50’s and no chance of rain in the forecast. Fished upper Watt Avenue and Paradise Beach on two days last week with no success. Two adult winter steelhead reported caught from the American River Friday/Saturday AM on Kiene’s Message Board. Posted picture of one fish looks like a bright hatchery adult with eroded dorsal (cannot see if the adipose fish is missing) but includes a Gary Anderson Rod two-handed rod and what looks like a Skagit w/tip setup.
Other Notes: The present Nimbus Fish Hatchery production mitigation goal for releases of winter steelhead progeny is 430,000 yearling size fish annually. Prior to 1995, several thousand and sometimes over one million fingerling size fish were additionally released. Also in the past, the majority of juvenile fish were released in late January and February in the Sacramento River near Garcia Bend. More recently, the release location has been change to the lower American River to reduce the incidence of adult fish straying. Hatchery personnel has met or exceeded the 430,000 juvenile fish production goal during eight of the past 11 years. Only during 1999, 2002, and more recently 2008, has that production goal not been met.
Typically, hatchery-produced American River winter steelhead progeny are released after about one year of hatchery (freshwater) rearing and the majority of adult steelhead return to the hatchery after two seasons of ocean growth. Since 1999, the progeny of all hatchery adult steelhead have been identified with an adipose fin mark prior to release. During the past 10 seasons, the majority (97.5%) of the adult steelhead trapped at the hatchery (and most likely in the American River) has been adipose fin marked and are most likely from Nimbus Fish Hatchery releases. Unfortunately, during the 2008 rearing period, high summer water temperatures at the hatchery required the early release of about one-half of the 2008 broodyear production. These fish were released in the Sacramento River at Garcia Bend and survival was expected to be low. The remaining 250,000 juvenile fish were released at the same location in February 2009.
In many instances, a stock recruitment relationship between the number of juvenile fish released and the number of returning adult fish has been demonstrated for many fish populations. However, a regression analysis (50+ years of data) of juvenile fish released and adult steelhead returns two years later does not demonstrate a strong relationship for fish released and trapped at Nimbus Fish Hatchery. This suggests that other factors (i.e. streamflows, water temperatures, ocean productivity, health of released fish, i.e.) are responsible for survival of juvenile fish and the number of returning adult steelhead once some threshold for the number of fish released is met. Unfortunately, the number of adult steelhead trapped at the hatchery during the past four seasons has been about 50% (about 1,000 adult fish) of the number trapped during the previous 10 seasons. There is no obvious explanation for the reduction (i.e. hatchery operations), which leaves unknown environmental conditions and maybe ocean productivity during the past four years as possible causes. Lack of an explanation, however, means there is no excuse for not being out there chasing the silver ghost.
Dennis
Dennis P. Lee
dpleeconsultants@comcast.net
916 293 1825 cellular
.
The American River flows remain stable at about 2,200 cfs, water temperatures about 52o F and clear. Weather is stable and sunny with daily highs in the high 50’s and no chance of rain in the forecast. Fished upper Watt Avenue and Paradise Beach on two days last week with no success. Two adult winter steelhead reported caught from the American River Friday/Saturday AM on Kiene’s Message Board. Posted picture of one fish looks like a bright hatchery adult with eroded dorsal (cannot see if the adipose fish is missing) but includes a Gary Anderson Rod two-handed rod and what looks like a Skagit w/tip setup.
Other Notes: The present Nimbus Fish Hatchery production mitigation goal for releases of winter steelhead progeny is 430,000 yearling size fish annually. Prior to 1995, several thousand and sometimes over one million fingerling size fish were additionally released. Also in the past, the majority of juvenile fish were released in late January and February in the Sacramento River near Garcia Bend. More recently, the release location has been change to the lower American River to reduce the incidence of adult fish straying. Hatchery personnel has met or exceeded the 430,000 juvenile fish production goal during eight of the past 11 years. Only during 1999, 2002, and more recently 2008, has that production goal not been met.
Typically, hatchery-produced American River winter steelhead progeny are released after about one year of hatchery (freshwater) rearing and the majority of adult steelhead return to the hatchery after two seasons of ocean growth. Since 1999, the progeny of all hatchery adult steelhead have been identified with an adipose fin mark prior to release. During the past 10 seasons, the majority (97.5%) of the adult steelhead trapped at the hatchery (and most likely in the American River) has been adipose fin marked and are most likely from Nimbus Fish Hatchery releases. Unfortunately, during the 2008 rearing period, high summer water temperatures at the hatchery required the early release of about one-half of the 2008 broodyear production. These fish were released in the Sacramento River at Garcia Bend and survival was expected to be low. The remaining 250,000 juvenile fish were released at the same location in February 2009.
In many instances, a stock recruitment relationship between the number of juvenile fish released and the number of returning adult fish has been demonstrated for many fish populations. However, a regression analysis (50+ years of data) of juvenile fish released and adult steelhead returns two years later does not demonstrate a strong relationship for fish released and trapped at Nimbus Fish Hatchery. This suggests that other factors (i.e. streamflows, water temperatures, ocean productivity, health of released fish, i.e.) are responsible for survival of juvenile fish and the number of returning adult steelhead once some threshold for the number of fish released is met. Unfortunately, the number of adult steelhead trapped at the hatchery during the past four seasons has been about 50% (about 1,000 adult fish) of the number trapped during the previous 10 seasons. There is no obvious explanation for the reduction (i.e. hatchery operations), which leaves unknown environmental conditions and maybe ocean productivity during the past four years as possible causes. Lack of an explanation, however, means there is no excuse for not being out there chasing the silver ghost.
Dennis
Dennis P. Lee
dpleeconsultants@comcast.net
916 293 1825 cellular
.