Fishway passage, water diversion and warming temperatures: Factors - - PowerPoint PPT Presentation

Fishway passage, water diversion and warming temperatures: Factors limiting successful spawning migration of Seton-Anderson watershed sockeye salmon

Scott Hinch David Roscoe Pacific Salmon Ecology and Conservation Laboratory

Background

• Research by the IPSFC in the 70s / 80s found that

sockeye were attracted to powerhouse tailrace on the Fraser River.

• Their experiments suggested potential dilution with

Cayoose Ck for Gates (20%) and Portage (10%) sockeye would maximize attraction into Seton River (these dilution rates used today).

• Still, migration mortality rates were ~ 10% and 30% for

these stocks respectively with these dilution levels.

Background

• First thorough evaluation of fishway attraction and

passage in 2005 by UBC

• Found 23% failure to enter fishway, but ~ 0% failure to

ascend fishway

• Found 33% of fish that exited fishway disappeared before

reaching spawning grounds; another 13% that exited were reported captured in fisheries

• Thus, previous work suggests cumulative mortality may

be high in the Seton Anderson watershed (~50% of fish that approach tailrace on Fraser do not reach spawning grounds).

• Needed was a study to examine relative levels of

mortality throughout the Seton system in a single year

Objectives of UBC 2007 study

• Quantify mortality along the migratory route in the

Seton-Anderson watershed

• Evaluate fishway effectiveness
• Assess impact of fishway on migration success
• Identify needs for management experiments and

future research

Seton River Entrance Fish water sluice Exit To Seton Lake

5 10 metres

N

Seton dam fishway – capture locale at top pool

Methods

• Captured 88 sockeye from top of Seton dam fishway
• Sockeye transported by truck to release site and held for

recovery in river

• Blood sampling (ions, lactate, glucose, hormones)
• Energy sampling (microwave fat meter)
• Implant acoustic telemetry transmitter,

temperature data logger

Seton Dam Seton Lake Fishway Cayoosh Diversion Dam Fraser River Hydro canal Power house Cayoosh Creek Seton Creek 1000 m

N

Methods

• Acoustic telemetry receiver array (lower section)

1 2 3 4,5 6-8 10 9

= release site

• Fish release sites

Fraser River Lillooet, B.C. 20 km

N

Anderson Lake Seton Lake Seton Dam

Gates Stock Spawning Area 11 12 13 14 15 17 16 10

• Acoustic telemetry receiver array (upper section)

50 100 150 200 250 300 350 400 450

Males Females Cortisol ( ng/ m L)

1 2 3 4 5 6 7 8 9 10

Males Females

Glucose ( m m ol/ L)

0.5 1 1.5 2 2.5 3

Males Females Lactate ( m m ol/ L)

250 260 270 280 290 300 310 320

Males Females Osm olality ( m m ol/ L)

Results – Physiological Stress Indices

• Sockeye not physiologically stressed or exhausted after

fishway ascent or transport (same as 2005 results). C R C R C R C R C R C R C R C R

• Mortalities and successful migrants did not differ in terms
• f most physiological measures.

Results: Mortality along the migratory route

Survival to spawning grounds was greater for males (71%

• f 17 fish) than females (40% of 38 fish; P=0.03).

No significant difference in survival between fish held for recovery and those released immediately.

Fish released upstream of dam Fate # % Successful migrant 26 93 Failed in Lake 2 7 Total 28 Fish released downstream of dam Fate # % Successful migrant 27 48 Failed in Lake 10 18 Failed at dam/fishway 10 18 Did not reach dam 8 14 Fishery removal 1 2 Total 56

Total loss = 52%

Results: Fishway evaluation

• 20% of tagged fish that reached the dam failed to pass

fishway in 2007.

• Failure largely due to ‘attraction’ to entrance rather than

passage through fishway.

10 20 30 40 50 60 70 80 90 100 Attraction Passage

Efficiency ( % )

100% 93% 77% 86% 2005 2007 2005 2007 n=30 n=51 n=23 n=44

Results Delay at different discharges in 2005 and 2007

Attraction efficiency at different discharges in 2005 and 2007 Results

Results

10 20 30 40 50 60 70 10 20 30 40 50 60 70 Dam spill discharge (m 3/ s) 10 20 30 40 50 60 70 80 90 100 Attraction efficiency (% )

10 6 5 36 4 13 6 8 48 5

• Lowest attraction and longest delay at highest discharge
• Not a simple relationship between discharge and attraction

Below dam delay (hrs)

60 cms 35 cms 12.7 cms

Results Temperature profiles of sockeye

2 4 6 8 10 12 14 16 18 20 22 20-Aug 22-Aug 24-Aug 26-Aug 28-Aug 30-Aug 1-Sep Temperature (

• C)

Arrival at spawning grounds Portage Creek Release into Seton Lake Anderson Lake 2 4 6 8 10 12 14 16 18 20 21-Aug 23-Aug 25-Aug 27-Aug 29-Aug 31-Aug Temperature (oC) Portage Creek Anderson Lake Arrival at spawning grounds Release into Seton Lake

• No thermal data for mortalities
• Very high and stressful

temperatures rarely experienced

• Thermal refuges utilized by some

individuals

F r a s e r R i v e r Portage Creek

N

Anderson Lake Seton Dam Spawning grounds Seton Lake

Summary

• Sockeye were in good physiological conditions after fishway

and ascent and transport.

• 48% of fish released downstream, and 93% of fish released

upstream of the dam reached spawning grounds.

• Mortality was higher for females (71%) than males (40%).
• 20% of sockeye unable to pass fishway and most of failure

associated with attraction to the entrance.

• Attraction into fishway and delay affected by discharge.
• Some fish (n = 5) were attracted to tailrace after falling back
• ut of lower Seton River. Could be related to seeking an

alternate route or a cool water refuge.

Recommendations 1) Temporary blockage in fishway could have serious consequences for populations of migrating sockeye. When fishway was temporarily blocked in 2007, some tagged sockeye (n = 3) moved out of the fishway and downstream to the Fraser River, and never returned to the fishway. The fishway exit should be monitored and maintained frequently (daily) during migration. Previous resistivity counter did not accurately count fish and may have impeded migration (UBC 2005 study). Managers should carefully consider effects of fish enumeration devices on passage and validate counts with videography and spawning escapement.

Recommendations 2) Some (n=5) fish in our study were attracted to the powerhouse tailrace on the Fraser River. 13% of tailrace ‘releases’ never made it to dam. Research is needed to quantify delay when sockeye initially encounter the powerhouse tailrace on the Fraser River.

Recommendations

3) Relationship between attraction and discharge is complex. High spill discharges (~60cms) from dam were associated with poor passage efficiency and long delays, small sample size. Management experiments are needed to examine relationships between discharge, flow patterns, attraction and delay.

Important questions to study:

• How do different discharges affect

hydraulics and attraction?

• use Acoustic Doppler Current Profiler

Can flow patterns (hence migration cues) be favourably altered via changes in water release at siphons?

• What are consequences of delay?

Entrance Attraction flow Siphons

Recommendations 4) Annual population assessments needed downstream of dam. These data should be used in conjunction with fishway counts, spawning ground escapements and telemetry experiments. We specifically recommend that research:

• use “fishway-naïve” individuals caught downstream of the dam
• minimize handling and capture stress (use trap-net / weir

approach)

Gates Creek sockeye

20,000 40,000 60,000 80,000 100,000 120,000

1950 1960 1970 1980 1990 2000 2010

# of spaw ners

2004 cycle 2005 cycle 2006 cycle 2007 cycle

2008

• IUCN Report on sockeye salmon to be released next week
• First ever global assessment of endangerment

status for a Pacific salmon species

Least Concern (no decline) Vulnerable (30% decline 3 generations) Endangered (50% decline) Critically Endangered (80% decline) Extinct in Wild Extinct

Fraser sockeye stock status

• 51 populations assessed
• 21 least concern
• 6 vulnerable
• 10 endangered
• 14 critically endangered

Gates Portage

IUCN Conclusions

• Gates Creek (“critically endangered”) and Portage Creek

(“vulnerable”) sockeye populations have had declining escapements in recent cycles (Salmonid Specialist report for

IUCN)

Thanks to …

Northern St’at’imc Fisheries

Bonnie Adolph, Elijah Michel, Terry Adolph

UBC Pacific Salmon Ecology & Conservation group: Lucas Pon, Marika Gale, Glenn Crossin,Ken Jeffries, Andrew Lotto

David Patterson, Jayme Hills

Steve Cooke - Carleton University