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Russian River Estuary Management. Jessica Martini-Lamb Principal Environmental Specialist [email protected]. www.sonomacountywater.org. The Influence of an Intermittently Closed, Northern California Estuary on the Feeding Ecology of Juvenile Steelhead ( Oncorhynchus mykiss ). - PowerPoint PPT Presentation
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Russian River Estuary Management
Jessica Martini-LambPrincipal Environmental Specialist
www.sonomacountywater.org
The Influence of an Intermittently Closed, Northern California Estuary on
the Feeding Ecology of Juvenile Steelhead (Oncorhynchus mykiss)
Erin Seghesio
Study ObjectiveTo determine over time and range, the distribution, composition and relative abundances of potential steelhead prey items and diet before and during a freshwater lagoon conversion.
Lower Reach: Highly saline, cooler temperatureMiddle Reach: Brackish, with three layersUpper Reach: Fresh water, very warm temperatures (22 degree)
Lower Reach: Highly saline, cooler temperature
Middle Reach: Brackish, with three layers
Upper Reach: Fresh water, very warm temperatures (22 degree)
Empirical Data Questions?
1. What are steelhead primary prey taxa?
2. Does steelhead prey vary by location (from freshwater to more saline)
3. Is there a response of primary salmonid prey to a closure?
Methods: Salmonid Diet Sampling -Beach seined-Gastric lavaged-12 sites-Monthly-Jun-Oct 2010
Methods: Invertebrate SamplingMonthly:Sampled 6 locations: June-Early SeptemberSampled 3 locations: June-October
Invertebrate sampling: Benthic Core-Taken along the shoreline -5 replicates per site
Invertebrate sampling: Nearshore Epibenthic Hauls-Pulled 10m perpendicular to the shoreline -5 replicates per site
Invertebrate sampling: Thalweg Epibenthic Sled-Towed from boat in the middle of the channel for 15 meters -5 replicates per site
Invertebrate sampling: Insect Fallout Trap and Zooplankton Vertical net haulsNot going to be covered today because zooplankton was not found in the diets and adult insects in very small quantities
2010 Estuary Closures
6/1/2010
6/6/2010
6/11/2
010
6/16/2010
6/21/2
010
6/26/2010
7/1/2010
7/6/2010
7/11/2010
7/16/2
010
7/21/2010
7/26/2
010
7/31/2
010
8/5/2010
8/10/2010
8/15/2
010
8/20/2010
8/25/2
010
8/30/2
010
9/4/2010
9/9/2010
9/14/2010
9/19/2
010
9/24/2010
9/29/2
010
10/4/2010
10/9/2010
10/14/2010
10/19/2010
10/24/2010
10/29/20100
1
2
3
4
5
6
7
8
Aver
age
Dai
ly W
ater
Hei
ght (
feet
)
2010 Estuary Closures and Seining Dates
6/1/2010
6/6/2010
6/11/2
010
6/16/2010
6/21/2
010
6/26/2010
7/1/2010
7/6/2010
7/11/2010
7/16/2
010
7/21/2010
7/26/2
010
7/31/2
010
8/5/2010
8/10/2010
8/15/2
010
8/20/2010
8/25/2
010
8/30/2
010
9/4/2010
9/9/2010
9/14/2010
9/19/2
010
9/24/2010
9/29/2
010
10/4/2010
10/9/2010
10/14/2010
10/19/2010
10/24/2010
10/29/20100
1
2
3
4
5
6
7
8
Aver
age
Dai
ly W
ater
Hei
ght (
feet
)
2010 Estuary Closures, Seining and Invertebrate Sampling Dates
6/1/2010
6/6/2010
6/11/2
010
6/16/2010
6/21/2
010
6/26/2010
7/1/2010
7/6/2010
7/11/2010
7/16/2
010
7/21/2010
7/26/2
010
7/31/2
010
8/5/2010
8/10/2010
8/15/2
010
8/20/2010
8/25/2
010
8/30/2
010
9/4/2010
9/9/2010
9/14/2010
9/19/2
010
9/24/2010
9/29/2
010
10/4/2010
10/9/2010
10/14/2010
10/19/2010
10/24/2010
10/29/20100
1
2
3
4
5
6
7
8
Aver
age
Dai
ly W
ater
Hei
ght (
feet
)
Empirical Data Questions?
1. What are steelhead primary prey taxa?
2. Does steelhead prey vary by location (from freshwater to more saline)
3. Is there a response of primary salmonid prey to a closure?
Steelhead feeding primarily on epibenthic taxa
Eogam
marus c
onfer
vicolu
s
Americo
rophiu
m spini
corne
Gnorim
osph
aerom
a ins
ulare
Ephem
eropte
ra ny
mph
Chiron
omida
e pup
a
Neomys
is merc
edis
juv-ad
ult
Chiron
omida
e larv
a
Hydrob
iidae
adult
Nereidi
dae
Corixid
ae ad
ult0
5
10
15
20
25
30
Inde
x of
Rel
ativ
e Im
porta
nce
(%)
Index of Relative Importance factors in:• Amount (numerical)• Weight (gravimetric)• Frequency of Occurrence
Some separation between reaches
ANOSIM: R=0.309, p=0.1%
FreshwaterBrackish/Slightly Salty
Empirical Data Questions?
1. What are steelhead primary prey taxa?
2. Does steelhead prey vary by location (from freshwater to more saline)
3. Is there a response of primary salmonid prey to a closure?
Benthic Core: Taxa did not move with closureJu
ne
July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Lower Reach
0
50000
100000
150000
200000
250000
June
July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Middle Reach
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
June July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Upper Reach
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
Den
sity
(tax
a/m
3 )
Shaded= Closed
Difference in species assemblages
ANOSIM R=0.527 p=0.1%
Nearshore Epibenthic Net: More motile organisms showed more movement with closure
June July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Lower Reach
0
200
400
600
800
1000
1200
1400
1600
1800
2000
June July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Middle Reach
0
100
200
300
400
500
600
700
800
June July
Augu
st
Oct
ober
Early
Sep
tem
ber
Late
Sep
tem
ber
Upper Reach
0
1000
2000
3000
4000
5000
6000
7000
Den
sity
(tax
a/m
3 )
Shaded= Closed
Thalweg Epibenthic Sled: Sites differences Ju
ne July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Lower Reach
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Den
sity
(tax
a/m
3 )
June July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Middle Reach
0
50
100
150
200
250
300
350
400
450
June July
Augu
st
Early
Sep
tem
ber
Late
Sep
tem
ber
Oct
ober
Upper Reach
0
100
200
300
400
500
600
700
800
900
Shaded=Closed
Empirical data findings-Steelhead are feeding primarily on epibenthic organisms.
-Although the highest density of common prey taxa were found in benthic core samples, the greatest diversity was in the epibenthic sampling.
-The more motile organisms are able to move into the newly flooded habitat during the short closures.
-Invertebrate assemblages varied by reach in response to salinity.
Empirical data findings-Steelhead are feeding primarily on epibenthic organisms.
-Although the highest density of common prey taxa were found in benthic core samples, the greatest diversity was in the epibenthic sampling.
-The more motile organisms are able to move into the newly flooded habitat during the short closures.
-Invertebrate assemblages varied by reach in response to salinity.
Empirical data findings- Steelhead are feeding primarily on epibenthic organisms.
-Although the highest density of common prey taxa were found in benthic core samples, the greatest diversity was in the epibenthic sampling.
-The more motile organisms are able to move into the newly flooded habitat during the short closures.
-Invertebrate assemblages varied by reach in response to salinity.
Empirical data findings-Steelhead are feeding primarily on epibenthic organisms.
-Although the highest density of common prey taxa were found in benthic core samples, the greatest diversity was in the epibenthic sampling
-The more motile organisms are able to move into the newly flooded habitat during the short closures.
-Invertebrate assemblages varied by reach in response to salinity.
Steelhead growthTemperaturePrey QualityCompetition
Consumption RatePrey Abundance
Question?
Q: Is steelhead growth going to be affected by an extended closure?
A: There was not an extended closure to sample
So we must model!
Wisconsin Bioenergetics Model (Hanson et. al 1997)
Consumption = Waste + Metabolism + GrowthAn energy balance equation
TemperatureBody massPrey Energy (J)Prey Composition
Metabolic Costs
Waste Loses
Growth
Consumption
Consumption= p* Cmax P-value: proportion of theoretical maximum
consumption
Diet composed of mostly lower caloric valued organisms
Gnorimosph-aeroma insulare
Corixidae (water boatman)
Americorophium spinicorne
Neomysis mercedis
Eogammarus confervicolus
Ephemeroptera nymph
Pictures from Jeff Cordell
Chironomidae Adult
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 250
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Temperature
Grow
th (g
/g*d
)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 250
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Temperature
Grow
th (g
/g*d
)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 250
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
Temperature
Grow
th (g
/g/d
)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 250
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
Temperature
Grow
th (g
/g*d
)
76% Cmax
62% Cmax
48% Cmax
20g2800 J/g
20g5000 J/g
120g2800 J/g
120g5000 J/g
The change in daily growth rate in response to temperature and feeding rates
Review of primary model findings• The more you eat the more you grow!
• Smaller fish are able to grow at a faster rate than larger fish, under the same circumstances.
• Steelhead can better buffer the stresses of increasing temperature and continue to grow by having at least one of the following:
1. Consuming higher quality prey2. Consuming more prey3. Being smaller
• Worst Case Scenario: 120g steelhead feeding at 48% of maximum consumption starts seeing no growth at 18°C
To overcome warmer temperature potentially associated with closure • Find refuge
• Feed on higher quality prey
• Increase consumption rate
Final Conclusions
• Steelhead are feeding primarily on lower calorie epibenthic organisms
• Although the highest density of common prey taxa were found in benthic core samples, the species were not able to move up the shoreline during the short closures
• Higher quality prey organisms do exist in estuary
• Higher prey energy values/greater consumption or finding refuge may allow steelhead to withstand warmer temperatures longer
Pescadero Creek Estuary J. Martin 1995 and M. Robinson 1993 studied fish diets and invertebrate populations
• Estuary went completely anoxic before converting to freshwater lagoon
• Killed significant amount of invertebrate population• Steelhead decreased stomach fullness factors and
growth rate
• Freshwater lagoon• Less diversity but greater abundances of invertebrate• Steelhead shifted diet from epibenthic crustaceans and
mysids to freshwater dependent nymphs and midges
Can be expected that steelhead in RR would make similar shift in diet
Flooded habitat created by closurePrevious research:-Shallow water habitat-Increase growth rate-Spatial segregation -Alleviate competition-Absence of predators -Increase in invertebrate production
The water quality during and after a closure is going to determine if the estuary/freshwater lagoon will be beneficial for steelhead
My final thought
Thank [email protected]
Field Support- Marshall Olin and Sonoma County Water Agency Staff
Lab and Data Support - Beth Armbrust, Claire Levy, Lia Stamatiou, Jeff Cordell, Jason Toft, Alex Ulmke, Ricky Tran and Wetlab Ecosystem Team
Committee Members- Charles “Si” Simenstad (PI), David Beauchamp, and Jeff Cordell (University of Washington)