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Seasonal Variations in Growth Physiology of Forage Fish

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

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Seasonal Variations in Growth Physiology of Forage Fish

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  1. Seasonal Variations in Growth Physiology of Forage Fish Ashwin Sreenivasan University of Alaska Fairbanks School of Fisheries and Ocean Sciences

  2. Juvenile Fish Growth • Affected by environmental variation: • seasonality • habitat • temperature • diet • Direct and indirect effects on growth • Complex interactions

  3. Juvenile Fish Growth • Growth • reproduction • condition • ecological growth models • Growth estimation methods • baseline data • seasonal metabolic patterns • population health

  4. 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

  5. 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

  6. 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

  7. Current ResearchForage 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

  8. Current Research • Collaboration: NOAA Auke Bay Laboratories Habitat Division • Field and lab component • Seasonal biology • Growth -temperature -diet • Integration of indices • Bioenergetic patterns/responses

  9. 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)

  10. 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)

  11. 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

  12. 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

  13. Objectives • Identify and compare temperature and diet influenced growth patterns in forage fish • Relate physiological growth patterns to survivability/resilience of forage fish stocks • Incorporate R/D patterns into R/D-temperature-growth models • Utilize growth patterns as inputs in formulating management plans

  14. Larval P.cod RNA/DNA comparison (2008)-Temperature

  15. Larval Pollock RNA/DNA comparison (2008)-Temperature

  16. Juvenile Herring RNA/DNA Comparison-Compensatory Growth/Temperature (2008 1st series)

  17. Juvenile Herring Lipid Comparison-Compensatory Growth/Temperature (2008 1st series)

  18. 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

  19. 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

  20. 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

  21. 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

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