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Title: Kootenai River White Sturgeon Recovery Implementation Plan and Schedule; 2005-2010, Technical Report 2004-2005.

Abstract

Kootenai River white sturgeon have been declining for at least 50 years and extinction of the wild population is now imminent (Paragamian et al. 2005). Only 630 adults were estimated to remain in 2002 from a population ten times that size just 20 years ago. Significant recruitment of young sturgeon has not been observed since the early 1970s and consistent annual recruitment has not been seen since the 1950s. The remaining wild population consists of a cohort of large, old fish that is declining by about 9% per year as fish die naturally and are not replaced. At this rate, the wild population will disappear around the year 2040. Numbers have already reached critical low levels where genetic and demographic risks are acute. The Kootenai River White Sturgeon Recovery Team was convened in 1994, provided a draft Recovery Plan in 1996 and the first complete Recovery Plan for Kootenai River white sturgeon in 1999 (USFWS 1996, 1999). The Plan outlined a four part strategy for recovery, including: (1) measures to restore natural recruitment, (2) use of conservation aquaculture to prevent extinction, (3) monitoring survival and recovery, and (4) updating and revising recovery plan criteria and objectives as new information becomesmore » available. Sturgeon recovery efforts are occurring against a backdrop of a broader ecosystem protection and restoration program for the Kootenai River ecosystem. With abundance halving time of approximately 8 years, the Kootenai River white sturgeon population is rapidly dwindling, leaving managers little time to act. Decades of study consistently indicate that recruitment failure occurs between embryo and larval stages. This assertion is based on four key observations. First, almost no recruitment has occurred during the last 30 years. Second, thousands of naturally produced white sturgeon embryos, most viable, have been collected over the past decade, resulting from an estimated 9 to 20 spawning events each year. Third, Kootenai River white sturgeon spawning has been documented during most years from 1990 through 2005. Finally, no larvae and very few wild juveniles have been collected during recent decades despite years of intensive sampling. Concurrently, post-release hatchery reared juveniles (as young as 9 months of age at release) consistently exhibit successful growth and survival (Ireland et al. 2002). Recruitment has failed, in part because fish are currently spawning at sites where or when conditions appear unsuitable for successful incubation and early rearing. Research to date suggests that recruitment failure is caused by egg or larval suffocation, predation and/or other mortality factors associated with these early life stages. A variety of interrelated factors have clearly contributed to the decline of Kootenai white sturgeon; various hypotheses for recruitment failure are not mutually exclusive. Anders et al. (2002) suggested that Kootenai River white sturgeon recruitment failure is likely the result of additive mortality from: (1) increased predation efficiencies due to low turbidity, velocity, and an relative increase in predatory fishes, (2) a reduced number of eggs produced by a dwindling spawning population, and (3) spawning in habitat lacking interstitial space (embryo suffocation). Quite simply, the combined egg and embryo mortality from all biotic and abiotic factors kills more eggs and embryos than the dwindling wild population is currently capable of producing. Thus, natural recruitment failure appears to be caused by some combination of habitat and stock limitation, by the mechanisms mentioned above. Although past research has helped narrow the range of possible causes of natural recruitment failure, the relative significance of each potential impact remains uncertain because multiple ecological, biological, and physical habitat changes occurred simultaneously. This makes it difficult to choose among competing hypotheses and difficult to know where exactly to focus recovery efforts for maximum benefit. In an ideal world, specific recovery measures would be identified and implemented based on a series of complementary research investigations to definitively identify the proximate causes and specific mechanisms of recruitment failure. The acute status of Kootenai sturgeon and current inability to compartmentalize the complex ecosystem do not afford the luxury of time for exhaustive research studies on every potential mechanism of recruitment failure. Mechanistic studies cannot replace the need for experimental evaluations of implemented adaptive management experiments.« less

Authors:
Publication Date:
Research Org.:
Bonneville Power Administration (BPA), Portland, OR (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
963294
Report Number(s):
DOe/BP-00019398-1
TRN: US200917%%507
DOE Contract Number:
19398
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
13 HYDRO ENERGY; ABUNDANCE; ADDITIVES; ADULTS; AQUACULTURE; ECOSYSTEMS; EMBRYOS; FISHES; GENETICS; HABITAT; IMPLEMENTATION; INCUBATION; INTERSTITIALS; JUVENILES; LARVAE; MONITORING; MORTALITY; REARING; RIVERS; TURBIDITY

Citation Formats

Anders, Paul. Kootenai River White Sturgeon Recovery Implementation Plan and Schedule; 2005-2010, Technical Report 2004-2005.. United States: N. p., 2007. Web. doi:10.2172/963294.
Anders, Paul. Kootenai River White Sturgeon Recovery Implementation Plan and Schedule; 2005-2010, Technical Report 2004-2005.. United States. doi:10.2172/963294.
Anders, Paul. Thu . "Kootenai River White Sturgeon Recovery Implementation Plan and Schedule; 2005-2010, Technical Report 2004-2005.". United States. doi:10.2172/963294. https://www.osti.gov/servlets/purl/963294.
@article{osti_963294,
title = {Kootenai River White Sturgeon Recovery Implementation Plan and Schedule; 2005-2010, Technical Report 2004-2005.},
author = {Anders, Paul},
abstractNote = {Kootenai River white sturgeon have been declining for at least 50 years and extinction of the wild population is now imminent (Paragamian et al. 2005). Only 630 adults were estimated to remain in 2002 from a population ten times that size just 20 years ago. Significant recruitment of young sturgeon has not been observed since the early 1970s and consistent annual recruitment has not been seen since the 1950s. The remaining wild population consists of a cohort of large, old fish that is declining by about 9% per year as fish die naturally and are not replaced. At this rate, the wild population will disappear around the year 2040. Numbers have already reached critical low levels where genetic and demographic risks are acute. The Kootenai River White Sturgeon Recovery Team was convened in 1994, provided a draft Recovery Plan in 1996 and the first complete Recovery Plan for Kootenai River white sturgeon in 1999 (USFWS 1996, 1999). The Plan outlined a four part strategy for recovery, including: (1) measures to restore natural recruitment, (2) use of conservation aquaculture to prevent extinction, (3) monitoring survival and recovery, and (4) updating and revising recovery plan criteria and objectives as new information becomes available. Sturgeon recovery efforts are occurring against a backdrop of a broader ecosystem protection and restoration program for the Kootenai River ecosystem. With abundance halving time of approximately 8 years, the Kootenai River white sturgeon population is rapidly dwindling, leaving managers little time to act. Decades of study consistently indicate that recruitment failure occurs between embryo and larval stages. This assertion is based on four key observations. First, almost no recruitment has occurred during the last 30 years. Second, thousands of naturally produced white sturgeon embryos, most viable, have been collected over the past decade, resulting from an estimated 9 to 20 spawning events each year. Third, Kootenai River white sturgeon spawning has been documented during most years from 1990 through 2005. Finally, no larvae and very few wild juveniles have been collected during recent decades despite years of intensive sampling. Concurrently, post-release hatchery reared juveniles (as young as 9 months of age at release) consistently exhibit successful growth and survival (Ireland et al. 2002). Recruitment has failed, in part because fish are currently spawning at sites where or when conditions appear unsuitable for successful incubation and early rearing. Research to date suggests that recruitment failure is caused by egg or larval suffocation, predation and/or other mortality factors associated with these early life stages. A variety of interrelated factors have clearly contributed to the decline of Kootenai white sturgeon; various hypotheses for recruitment failure are not mutually exclusive. Anders et al. (2002) suggested that Kootenai River white sturgeon recruitment failure is likely the result of additive mortality from: (1) increased predation efficiencies due to low turbidity, velocity, and an relative increase in predatory fishes, (2) a reduced number of eggs produced by a dwindling spawning population, and (3) spawning in habitat lacking interstitial space (embryo suffocation). Quite simply, the combined egg and embryo mortality from all biotic and abiotic factors kills more eggs and embryos than the dwindling wild population is currently capable of producing. Thus, natural recruitment failure appears to be caused by some combination of habitat and stock limitation, by the mechanisms mentioned above. Although past research has helped narrow the range of possible causes of natural recruitment failure, the relative significance of each potential impact remains uncertain because multiple ecological, biological, and physical habitat changes occurred simultaneously. This makes it difficult to choose among competing hypotheses and difficult to know where exactly to focus recovery efforts for maximum benefit. In an ideal world, specific recovery measures would be identified and implemented based on a series of complementary research investigations to definitively identify the proximate causes and specific mechanisms of recruitment failure. The acute status of Kootenai sturgeon and current inability to compartmentalize the complex ecosystem do not afford the luxury of time for exhaustive research studies on every potential mechanism of recruitment failure. Mechanistic studies cannot replace the need for experimental evaluations of implemented adaptive management experiments.},
doi = {10.2172/963294},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}

Technical Report:

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  • The objective of this research was to determine the environmental requirements for successful spawning and recruitment of the Kootenai River white sturgeon Acipenser transmontanus population. Annual tasks include monitoring and evaluating the response of various life stages of Kootenai River white sturgeon to mitigation flows supplied by the United States Army Corps of Engineers (USACE). Sampling for adult Kootenai River white sturgeon in 2004 began in March and continued into May. One hundred forty-two adult white sturgeon were captured with 4,146 hours of angling and set-lining effort in the Kootenai River. Kootenai River discharge and stage at Bonners Ferry inmore » 2004 peaked in mid December. Discharge remained below 400 cubic meters per second (cms) until June 1; then, because of a systems operations request (SOR), increased and remained between 480 and 540 cms through the end of June. From July through September, discharge ranged from 360 to 420 cms, decreasing to 168 cms by the end of October. Discharge increased again to above 625 cms by November 4 to increase winter storage in Lake Koocanusa and ranged from 310 to 925 cms through the end of December. We monitored the movements of 31 adult sturgeon in Kootenay Lake, British Columbia (BC) and the Kootenai River from mid-March until late August 2004. All telemetered fish were dual tagged with external sonic and radio transmitters, and some of the fish were tagged in previous years. Eighteen of the 31 telemetered adult white sturgeon were released at Hemlock Bar reach (rkm 260.0) as part of a research project to test the feasibility of moving sexually mature adult white sturgeon to areas with habitat types thought to be more suitable for successful egg hatching and early life stage recruitment. Marked fish were monitored from the time of release until they moved downstream of Bonners Ferry. Sampling for white sturgeon eggs with artificial substrate mats began May 3 and ended June 10, 2004. We sampled 650 mat days (a mat day is one 24 h set) during white sturgeon spawning. Most of the sampling occurred in the post-Libby dam spawning reach (rkm 229.0 to 246.0) but some sampling occurred near Crossport (rkm 253.5) and in the Canyon reach above Hemlock Bar (rkm 261.0). We collected eight white sturgeon eggs near Shortys Island in 2004. Sampling for larval white sturgeon began June 8 and continued until July 22, 2004. Sampling occurred primarily at Ambush Rock (rkm 244.0) in an attempt to document any recruitment that might have occurred from the Set and Jet Program. We collected 103 larval fish, but none were white sturgeon larvae or embryos. Juvenile white sturgeon sampling started July 26 and continued through September 27, 2004. A total of 271 hours of gillnetting effort captured 256 juvenile hatchery white sturgeon and two juvenile wild white sturgeon.« less
  • The objective of this research was to determine the environmental requirements for successful spawning and recruitment of the Kootenai River white sturgeon Acipenser transmontanus population. Annual tasks include monitoring and evaluating the various life stages of Kootenai River white sturgeon. Sampling for adult Kootenai River white sturgeon in 2003 began in March and continued through April. Eighty-one adult white sturgeon were captured with 3,576 hours of angling and set-lining effort in the Kootenai River. Discharge from Libby Dam and river stage at Bonners Ferry in 2003 peaked in May and early June. Flows remained above 500 m{sup 3}/s throughout June,more » decreased rapidly through mid July, and increased back to near 500 m{sup 3}/s after mid July and through mid August. By late August, flows had decreased to below 400 m{sup 3}/s. We monitored the movements of 24 adult sturgeon in Kootenay Lake, British Columbia (BC) and the Kootenai River from March 15, 2003 to August 31, 2003. Some of the fish were radio or sonic tagged in previous years. Twelve adult white sturgeon were moved upstream to the Hemlock Bar reach (rkm 260.0) and released as part of the Set and Jet Program. Transmitters were attached to seven of these fish, and their movements were monitored from the time of release until they moved downstream of Bonners Ferry. Eight additional radio-tagged white sturgeon adults were located in the traditional spawning reach (rkm 228-240) during May and June. Sampling with artificial substrate mats began May 21, 2003 and ended June 30, 2003. We sampled 717 mat d (a mat d is one 24 h set) during white sturgeon spawning. Three white sturgeon eggs were collected near Shortys Island on June 3, 2003, and five eggs were collected from the Hemlock Bar reach on June 5, 2003. Prejuvenile sampling began June 17, 2003 and continued until July 31, 2003. Sampling occurred primarily at Ambush Rock (rkm 244.0) in an attempt to document any recruitment that might have occurred from the Set and Jet Program. Sixteen larval fish were collected, but no prejuvenile white sturgeon were collected. Juvenile white sturgeon sampling started July 14, 2003 and continued through September 18, 2003. A total of 330 h of gillnetting effort captured 238 hatchery white sturgeon and three wild white sturgeon.« less
  • Natural reproduction in the Kootenai River white sturgeon population has not produced a successful year class since 1974, resulting in a declining broodstock and 20 consecutive year classes missing from the age-class structure. This report describes a captive breeding plan designed to preserve the remaining genetic variability and to begin rebuilding the natural age class structure. The captive breeding program will use 3--9 females and an equal number of males captured from the Kootenai River each spring. Fish will be spawned in pairs or in diallel mating designs to produce individual families that will be reared separately to maintain familymore » identity. Fish will be marked to identify family and year class before return to the river. Fish should be returned to the river as fall fingerlings to minimize potential adaptation to the hatchery environment Initially, while tagging methods are tested to ensure positive identification after return to the river, it may be necessary to plant fish as spring yearlings. Number of fish planted will be equalized at 5,000 per family if fall fingerlings or 1,000 per family if spring yearlings. Assuming annual survival rates of 20% during the first winter for fall fingerling plants and 50% for years 1--3, and 85% for years 4--20 of all fish planted, the target numbers would yield 7.9 progeny per family or about 4 breeding pairs at age 20. Natural survival in the river environment during the 19+ years from planting to maturity would result in variability in genetic contribution of families to the next broodstock generation. Fish planted per family would be adjusted in future years when actual survival rate information is known. Broodfish will be tagged when captured to minimize multiple spawning of the same fish. implementation of this breeding plan each year for the 20-year generation interval, using 5 different mating pairs each year, will yield an effective population size of 200, or 22.5% of the estimated 1990 population.« less
  • Test flows for Kootenai River white sturgeon Acipenser transmontanus spawning, scheduled for June 1996, were postponed until July. However, an estimated 126% snow pack and unusually heavy precipitation created conditions for sturgeon spawning that were similar to those occurring before construction of Libby Dam. Discharge in the Kootenai River at Bonners Ferry rose to nearly 1,204 m{sup 3}/s (42,500 cfs) during May and water temperature ranged from 5.8 C to 8.4 C (42 F to 47 F). Migration of adult white sturgeon into spawning areas occurred in late May during a rising hydrograph. Discharge and water temperature were rising andmore » had reached approximately 1,077 m{sup 3}/s (38,000 cfs) and 8 C (46 F). Discharge at Bonners Ferry peaked at about 1,397 m{sup 3}/s (49,300 cfs) on June 5. A total of 348 eggs (and one egg shell) were collected with 106,787 h of mat effort during the flow events. The first white sturgeon eggs were collected on June 8 and continued through June 30. Staging of eggs and back-calculating to spawning dates indicated there were at least 18 spawning episodes between June 6 and June 25. Discharge on June 6 was 1,196 m{sup 3}/s (42,200 cfs) and decreased steadily to 850 m{sup 3}/s (30,000 cfs) by June 26. Although sturgeon spawned in the same reach of river that they had during 1994 and 1995, the majority of eggs were found significantly (P = 0.0001) farther upstream than 1994 and 1995 and this in turn may be related to elevation of Kootenay Lake.« less
  • Flows in the Kootenai River for white sturgeon Acipenser transmontanus spawning in 1998 were expected to be at a minimum because the snow pack in the basin was only about 79% normal, and local inflow was expected to be very low, <142 m{sup 3}/s (5,000 cfs). Flows in the Kootenai River at Bonners Ferry from late April through early May were at about 425 m{sup 3}/s (15,000 cfs) while water temperature ranged from about 8 to 10 C (45 to 50 F). Spawning and incubation flows from Libby Dam began on May 18 when flow at the dam was broughtmore » up to 765 m{sup 3}/s (27,000 cfs). Unusually frequent rains and several enormous storms brought peak flows at Bonners Ferry to over 1,175 m{sup 3}/s (41,500 cfs) on May 27, temperature ranged between 8 and 10.6 C (45 to 51 F). Flow gradually subsided at Bonners Ferry during June and was steady at 708 to 765 m{sup 3}/s (25,000 to 27,000 cfs) while temperature gradually rose to 14.4 C (58 F). Forty-seven adult white sturgeon were captured with 4,220 hours of angling and setlining effort between March 1 and April 15, 1998 by the Idaho Department of Fish and Game (IDFG). Sonic and radio tags were attached to four female and five male sturgeon during this effort. From April 1 through July 31, 1998, a total of 17 fish were monitored specifically for pre-spawn and spawning activities. White sturgeon spawning location, timing, frequency, and habitat were evaluated by sampling for eggs with artificial substrate mats. Four hundred and eighty-four eggs were collected, 393 eggs (81%) were collected on 60 standard mats, and 91 eggs (19%) were collected on seven experimental mats with drift nets. Ten eggs collected with experimental mats were found mixed with sand, suggesting eggs are moving in the lower water column with sand. The middle Shorty's Island reach (rkm 229.6-231.5) produced the most eggs (173) while the Deep Creek section (rkm 237.6-240.5) produced 112 eggs. No eggs were collected above the Deep Creek section (>rkm 240.5). Four hundred and twenty (87%) of the 484 white sturgeon eggs collected in 1998 were viable. Development ranged from stage 12 to 28 (1 h to 12 d old), with 95% of the viable eggs at stage 21 (about 2.4 days) or earlier. The oldest egg was estimated at 293 hours old or about 12 days. Based on ages of viable eggs and the dates of egg collection, we estimated that white sturgeon spawned during at least 20 days in 1998. The first spawning episode was estimated to have occurred on May 6. The next episode was estimated to have occurred May 7 with a gap in spawning until May 10. Thereafter, spawning occurred for the next three days with a second break. From May 22, spawning occurred nearly every day through June 6. Peak spawning appeared to occur between from May 23 through May 28. Juvenile sampling yielded 163 individual fish (several fish were recaptured) of which 160 were hatchery and three wild sturgeon recruited from flow test years. Food habit studies of hatchery age-3 sturgeon indicated Chironomids comprised about 36% of the total food items by number while the Ephemeropterans Ephemerellidae and Baetidae contributed 22%. Continuous seismic profiling of a 12-km (7.45 mi) reach of the Kootenai River (rkm 228-240) indicated the riverbed was comprised primarily of fine and coarse sand. There was no evidence to suggest pre-dam gravels were overlain with sand. Recommendations for the 1999 spawning season include coordinating the flow test with sturgeon behavior and river temperatures of 8-10 C (46-50 F), and discharge should be in increments of 57 m{sup 3}/s (2,000 cfs) per day to a minimum of 1,130 m{sup 3}/s (40,000 cfs) at Bonners Ferry. We also recommend no load following.« less