Seasonal Variations in
Growth Physiology of
Forage Fish
Ashwin Sreenivasan
University of Alaska Fairbanks
School of Fisheries and Ocean Sciences
Juvenile Fish Growth
• Affected by environmental variation:
– seasonality
– habitat
– temperature
– diet
• Direct and indirect effects on growth
• Complex interactions
Juvenile Fish Growth
• Growth
– reproduction
– condition
– ecological growth models
• Growth estimation methods
– baseline data
– seasonal metabolic patterns
– population health
Physiological Growth Estimation
• Physiological growth indices
– growth at tissue level
• Influence of specific parameters
– biotic and abiotic
• Growth responses across taxa
• Vital inputs in ecological growth models
Physiological Indices Criteria
• Desired characteristics of a growth index
- sensitivity
- rapidity of response
- utility in meshing field and lab data
• Physiological growth indices exhibiting
above criteria
– cellular metabolic enzyme activity
– cellular RNA/DNA ratios
Cellular RNA/DNA (R/D) Ratio
• DNA-cell number/biomass
• RNA-protein synthesis
• Nutritional stress
-RNA fluctuation
• RNA concentration/activity variation
– protein synthesis
– tissue growth
– nutritional condition
Current Research
Forage Fish
• Forage fish-Pacific herring, larval gadids (P.cod,
•
•
pollock)
– critical ecological importance in Alaskan
waters
Cascade effect
– key prey
– Pacific cod, walleye pollock, salmon
Seasonal growth physiology
-temperature stress
-overwinter stress
-starvation stress & recovery
Current Research
• Collaboration: NOAA Auke
•
•
•
•
•
Bay Laboratories Habitat
Division
Field and lab component
Seasonal biology
Growth
-temperature
-diet
Integration of indices
Bioenergetic
patterns/responses
Research Study Samples
• Juvenile Pacific herring (Clupea pallasii) growth (2008 1st
and 2nd series)
– habitat
– temperature (6oC, 8.5oC, 12.5oC)
– diet (starvation/compensatory growth)
• Larval Pacific cod (Gadus macrocephalus) growth (2008
& 2009)
– temperature (5oC, 8oC)
– diet
• Larval Walleye pollock (Theragra chalcogramma) growth
(2008 & 2009)
– temperature (5oC, 8oC)
• Lab component: herring
study
– Marrowstone Marine
Laboratory (USGS)
– 0+/1+ herring growth
– temperature/diet (6oC,
8.5oC, 12.5oC)
– 2 phases: feeding and
starvation
– 3 temperatures
– periodic sampling
– March 2008
– comprehensive
seasonal growth
information (R/D,
lipids, proteins)
• Lab component: cod
study
– Hatfield Marine
Science Center (NOAA)
– 0+ P.cod growth
– temperature/diet
– 2 concurrent phases
– 3 temperatures
– 4 diets
– periodic sampling
– April-May 2008
– preliminary larval
growth data
– repeat in 2009
• Lab component: pollock
•
study
– Hatfield Marine
Science Center (NOAA)
– 0+ pollock growth
(larvae)
– 2 temperatures
– periodic sampling
– April-May 2008
– preliminary larval
growth data
repeat in 2009
Objectives
1. Identify and compare temperature and diet
2.
3.
4.
influenced growth patterns in forage fish
Relate physiological growth patterns to
survivability/resilience of forage fish stocks
Incorporate R/D patterns into R/Dtemperature-growth models
Utilize growth patterns as inputs in formulating
management plans
Larval P.cod RNA/DNA
comparison (2008)-Temperature
10
0.16
8 Degrees
Growth Rate (mm/day)
8
7
6
5
5 Degrees
0.14
8 Degrees
0.12
0.1
0.08
0.06
4
0
5
10
15
20
25
30
35
22
40
26
30
34
Days Post Hatch
Days Post Hatch
6
5 degrees
5.5
R/D Ratio
Length (mm)
5 Degrees
9
8 degrees
5
4.5
4
3.5
0
10
20
Days Post Hatch
30
40
38
5 degrees
0
10
20
30
Days Post Hatch
Growth Rate (mm/day)
16
14
12
10
8
6
4
2
0
8 degrees
40
0.25
0.2
0.15
0.1
0.05
5 degrees
50
18
23
28
33
Days Post Hatch
10
8
6
4
2
5 degrees
8 degrees
0
0
10
8 degrees
0
12
R/D ratio
Length (mm)
Larval Pollock RNA/DNA comparison
(2008)-Temperature
20
30
Days Post Hatch
40
50
38
Juvenile Herring RNA/DNA
Comparison-Compensatory
Growth/Temperature (2008 1st series)
Ambient Tanks Herring R/D (8.5oC)
9
8
R/D Ratio
7
6
5
4
3
2
Starved/Refed
1
Fed
0
3/13
4/12
5/12
6/11
Date Sampled
Cold Tanks Herring R/D (6oC)
Hot Tanks Herring R/D (12.5oC)
10
8
7
8
6
6
5
4
4
3
Starved/Refed
2
0
3/13
7/11
Fed
4/2
4/22
5/12
Date Sampled
6/1
2
1
6/21
0
7/11 3/13
Starved/Refed
3/23
4/2
4/12
4/22
Date Sampled
5/2
5/12
5/22
6/1
Juvenile Herring Lipid ComparisonCompensatory Growth/Temperature
(2008 1st series)
Ambient Tank Herring Lipid %
12
Lipid %
10
8
6
4
Starved/Refed
2
Fed
0
3/23
4/2
4/12
4/22
5/2
5/12
5/22
6/1
6/11
6/21
7/1
Date sampled
Hot Tank Herring Lipid %
Cold Tank Herring Lipid %
14
12
12
10
10
8
8
6
6
4
Starved/Refed
2
Fed
0
4/12
4/22
5/2
5/12
5/22
6/1
Date sampled
6/11
6/21
4
2
7/1
0
7/11 3/13
Starved/Refed
3/23
4/2
4/12
4/22
Date sampled
5/2
5/12
5/22
6/1
Applications-Growth Performance
• RNA activity-temperature caveat
• R/D-growth-temperature calibration
models
• Growth performance (Gpf=G/Gmax)
• Measure of larval condition
• Formulation of reference growth rate (Gref)
• Estimated Gpf across species
Growth Performance
• Applications to Pacific herring-specific
growth models
• R/D-growth-temperature models for
starved herring across temperatures
• Possible R/D cutoff point
• Understanding growth during seasonal
(winter) starvation and recovery periods in
herring life-history
Ongoing Research
• RNA/DNA analyses:
-juvenile herring (2nd stage replication)
-juvenile cod & pollock (2009 samples)
• Metabolic enzyme analyses:
-juvenile herring (2008 samples)
• Incorporation of R/D data into species
specific growth models
Acknowledgements
• Rasmuson Fisheries Research Center
Board
• School of Fisheries and Ocean Sciences
• Dr. Bill Smoker
• NOAA Auke Bay Laboratory
• Dr. Stanley Rice, Dr. Ron Heintz, and J.J.
Vollenweider