New Science

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New Science New Regulations
Bruce Herbold (EPA) IEP and POD Management Teams
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Fall abundance in 2008 continued low for all POD
fishes.
Source DFG 2008 Fall MW Trawl No sampling 1974
and 1979
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TOP-DOWN
Water Diversions
Predation
PHYSICAL CHEMICAL FISH HABITAT
FISH ABUNDANCE
Prior Fish Abundance
Temperature Turbidity Salinity
Contaminants
Disease
Food availability

Food quality
Toxic algae SAV
BOTTOM-UP
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Water Project Losses
Up to 35-65 Percent of Delta Inflow
Fish Facilities Provide Data on Numbers
Salvaged
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Winter Salvage (Nov-Mar)
Longfin smelt
Delta smelt
Striped Bass
250,000
Threadfin Shad
2,500,000
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Fall abundance in 2008 continued low for all POD
fishes.
Source DFG 2008 Fall MW Trawl No sampling 1974
and 1979
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Old and Middle Rivers as an Integrator of
Hydrodynamic Effects
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Negative Old Middle River Flows Apparently
Increase Adult Delta Smelt Entrainment
r2 0.31, plt0.05
Delta Smelt SWP CVP Salvage (log count)
Combined Old Middle River Flow (cfs)
Mean Values for December-March
Source Source Lenny Grimaldo (In Review)
1993-2005
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First Flush/turbidity spike
Winter
14 days of OMR -2000 cfs
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Spawning (templt12 C)
Late Winter-Spring
OMR -3500 to -5000 cfs
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Downstream Movement (temp 12-25 C)
Spring
OMR -1250 to -5000 cfs
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Rearing ( about 1 ppt salinity)
Fall
Typical Distribution
Wet year outflow 7000-11,000 cfs
Source Sommer et al. In review
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TOP-DOWN
Water Diversions
Predation
PHYSICAL CHEMICAL FISH HABITAT
FISH ABUNDANCE
Prior Fish Abundance
Temperature Turbidity Salinity
Contaminants
Disease
Food availability

Food quality
Toxic algae SAV
BOTTOM-UP
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Fall habitat quality deteriorated
Striped bass
Delta smelt
Source Feyrer et al. (CJFAS 2007)
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Fall habitat quality matters to the delta
smelt population
Fall EQ Fall Abundance predicts juvenile
production
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Increased outflow more longfin smelt.
Pre-clam
Upper Estuary relation changed
Post-clam
Fall Midwater Trawl
POD years
Lower Estuary relation unchanged
Bay Study Otter Trawl
Source Randy Baxter, DFG
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Where the smelt are in the bay
a
b
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Other habitat stressors

• Bioassays showed little effect (lt5 ) in 2005 or
  2006.
• lt15 adult delta smelt impaired
• 100 of young striped bass show multiple
  infections
• Little evidence of toxicity

Source Inge Werner, Swee Teh, and Dave Ostrach
(UCD)
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• POD Nutrients
• Example Ammonia pollution

Sewage Treatment Plants
Increasing Ammonia levels in Delta and Suisun Bay
Potential Ecosystem Effects
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90 of the Ammonia Load at Hood comes from the
Sacramento Regional Wastewater Treatment Plant
Sources A. Mueller-Solger, DWR A. Jassby, in
press SFEWS
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Widespread blooms of the toxic alga Microcystis
in 2007
August Levels 1.3 million cells/mL
Microcystis grows well on ammonia! (Diatoms dont)
Core Habitat of Delta Smelt
Source Peggy Lehman (DWR)
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July August 2007 Microcystis bloom and smelt
effects
L55
Fish zooplankton collection
August Microcystis bloom
Sept delta smelt distribution
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Alternative Life Histories
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A Major Emphasis on Habitat Restoration to
Boost the Delta Food Web
FISH ABUNDANCE
Food availability

Food quality
BUT only local effect likely
BOTTOM-UP
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TOP-DOWN
Water Diversions
Predation
PHYSICAL CHEMICAL FISH HABITAT
FISH ABUNDANCE
Prior Fish Abundance
Temperature Turbidity Salinity
Contaminants
Disease
Food availability

Food quality
Toxic algae SAV
BOTTOM-UP
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Food Affects Summer Smelt Survival
Delta Smelt
Zooplankton
(Jul-Oct)
Source Wim Kimmerer (In review)
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Stock - Recruitment Effects
Threadfin shad
Juvenile Production
Delta smelt
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Have Delta Smelt Dropped Below Critical
Population Levels?
Juvenile (TNS)
Recent Trend
Adults (FMWT)
Source Anke Mueller-Solger (DWR)
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Striped Bass Revisited
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Whats Wrong With This Picture?
Juveniles
Age-O
Townet index
Adults
Adults
Adult abundance (1000)
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What Happened To All Of The Mamas?
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Gill Net Sampling
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Percent Females
20
10
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Effect of Sex Shift on Population?
Petersen Estimates
Adults
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Effect of Sex Shift on Population?
Petersen Estimates
Adults
Gill Net Sex Ratio Applied to Petersen Estimates
Adults
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• Flow
• Phosphorus
• Ammonia
• Temperature
• Contaminants
• Harvest
• turbidity

• Low and Constant
• Limited
• Lots
• Warm
• High
• High
• Low

• Highly variable
• Lots
• Little
• Cool
• Low
• Low
• High

• Clams
• Jellyfish
• Edge and benthic fish
• Microcystis
• Aquatic Weeds

Diatoms Pelagic fish Natives thrive Resists
invasions
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