Climate Change and Halibut Biology

1
Climate Change and Halibut Biology

• Year 2 progress report and activities

2
Overall goal of research project

• Investigate interdecadal changes in growth and
  recruitment of Pacific halibut and their
  relationship to North Pacific climate variability
• The 1997 Review Panel endorsed The IPHC
  initiative to conduct more research on the
  environment targeted specifically to growth,
  reproduction, and recruitment." They noted that
  this work was important for distinguishing
  environmental from density-dependent effects

3
1997-98 project activities

• Definition of North Pacific decadal-scale climate
  variability and regime shifts
• Compilation of a North Pacific ocean bottom
  properties database
• Developed conceptual bottom up model of
  population variability
• Examined patterns of recruitment variability for
  North Pacific pelagic, groundfish and salmon
  species
• Formation of working relationships with other
  climate-fisheries research groups

4
North Pacific Climate

• A relatively new theory on climate variability in
  the North Pacific is being developed
• Three major sources of variability
• 1. Seasonal variation (annual)
• 2. El Niño - Southern Oscillation (interannual)
• 3. Pacific Decadal Oscillation (interdecadal)

Mantua, N. J., S. R. Hare, Y. Zhang, J.M.
Wallace, and R.C. Francis. 1997. A Pacific
interdecadal climate oscillation with impacts on
salmon production. Bull. Amer. Meteor. Soc. 78
1069-1079.
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Pacific climate variability, 1900-1997
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Physical and biological changes associated with
the PDO

• Warmer air and sea temperatures
• Decreased precipitation
• decreased upper ocean mixed layer depth

• Plankton, salmon (Alaska), flatfish populations
  increased
• Crustaceans, marine birds, marine mammals, salmon
  (West Coast) declined

7
Conceptual Model of Climatically-Driven Ecosystem
Change
Francis, R. C., S. R. Hare, A. B. Hollowed, and
W. S. Wooster. 1998. Effects of interdecadal
climate variability on the oceanic ecosystems of
the NE Pacific. Fish. Oceanogr. 7 1-21.
8
Patterns of recruitment variability
Salmon catches
Groundfish and pelagic recruitment
SPECIES SIGNAL EFFECT EBS A. flounder PDO
EBS G. turbot PDO - GOA A.
flounder PDO GOA P. halibut PDO
WC P. hake ENSO GOA pollock ENSO
GOA P. cod ENSO
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Recruitment publications
Hollowed, A. B., S. R. Hare, and W. S. Wooster.
In Press.Pacific - Basin Climate Variability and
Patterns of Northeast Pacific Marine Fish
Production. Proceedings of the 10th 'Aha Huliko'a
Hawaiian Winter Workshop on Biotic Impacts of
Extratropical Climate Variability in the Pacific,
January 26-29, 1998.
Hare, S. R., N. J. Mantua and R. C. Francis.
1999. Inverse production regimes Alaskan and
West Coast Salmon. Fisheries 24(1).
10
Ocean Bottom Properties Database

• Database for use in environmental studies
• Compilation of 145,000 records of near-bottom
  observations on temperature, salinity, dissolved
  oxygen and nutrients
• Geographic coverage Bering Sea to California,
  continental shelf and slope to 1000 m
• Sources include agency, university, foreign
  collections
• Funding being sought to digitize other
  collections
• Frequent requests for data

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Ocean Bottom Temperature data, by decade
12
Decadal variation in bottom temperatures
change from 1971-76 to 1977-82
change from 1986-90 to 1991-95
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Current and ongoing research

• Continue research on nature of climate
  variability
• Continue retrospective analyses using the ocean
  properties database
• Analyze historical variations in otolith growth
• Collaboration on basin-wide zooplankton biomass
  variability study
• Compare growth studies across groundfish species
• Construct environmentally based recruitment index
  (joint work with Bern Megrey)
• Work on planning two IPHC co-sponsored symposia
  on interdecadal variability in groundfish stocks

14
Climate questions under investigation

• What is the relationship between ENSO and PDO?
• Is the PDO driven by tropical or extra-tropical
  processes?
• Are there more than two regime states?
• Has there been a regime shift since 1977?
• Do conditions at depth follow those at the
  surface?

15
Development of OBT indices

• Interannual bottom temperature indices are being
  developed for each of the major IPHC regulatory
  areas
• These indices are critical for the following
  years growth studies and continued research into
  decadal climate variability
• Their use as recruitment indices will also be
  explored

16
Retrospective analysis of ocean properties
database

• Ongoing, will continue through the year
• Define climatic variability and regime shift
  influence at depth
• Produce temperature maps through time for use
  with stable isotope study
• Produce IPHC area bottom temperature indices for
  use with otolith growth study

17
Extend Hagen and Quinn otolith growth study

• Six months for selection and reading of otoliths
  and data analysis
• H Q study followed 1953-78 year classes - all
  within one regime. Can extend forward 10 years,
  perhaps backwards as well.
• H Q used SST as environmental index - can redo
  their analysis with more suitable indices

18
Compare growth across groundfish species

• 2-3 months analysis following collection of data
• Compare temporal changes in growth across
  different flatfish species, different groundfish
  (sablefish, rockfish), and different areas.
• Should provide information on whether
  interspecific density dependence is limiting
  halibut and groundfish growth

19
Construct environmentally-based recruitment index

• Work is ongoing
• Explore best environmentally-based recruitment
  index, similar to what was done with walleye
  pollock
• Compare multivariate techniques for prediction
  capability.

20
Collect juvenile halibut samples

• Attempt to apply Biological Intercept method of
  Campana in otolith-based growth back-calculations
• Requires otolith and body size samples of
  juveniles
• Pete Hagen has additional data for analysis

21
Symposium on interdecadal changes in groundfish
biology

• Long-term changes noted in several groundfish
  populations
• IPHC can take the lead in organizing a dedicated
  symposium comparing changes and techniques for
  detecting and explaining observed changes