Effects of oceanographic barriers, habitat discontinuity, and geographic distance on population stru

1
Effects of oceanographic barriers, habitat
discontinuity, and geographic distance on
population structure of copper rockfish, Sebastes
caurinus, along the Oregon coast

• Mattias Johansson1, Heather Hassel2, Katie
  Glunt2, Michael Banks1, Vince Buonaccorsi2

1 Hatfield Marine Science Center, Oregon State
University, Newport, OR 2 Department of Biology,
Juniata College, Huntingdon, PA
2
Pacific Coast Rockfishes

• Diverse and successful
• Vulnerable to local overfishing
• Commercial, recreational, live fish fisheries
• Specific management data lacking
• Larval dispersal determines population
  connectivity

3
Evidence of Isolation by DistanceBuonaccorsi et
al. (2002)
4
Sampling

• 1 location in WA
• 49 Samples
• 7 locations in OR
• Close spacing around putative barriers
• 515 Samples
• 4 locations in CA
• 185 Samples
• 749 Total Samples

5
Goals

• Assess relatedness of Oregon populations in
  relation to California and Washington
• Determine whether significant genetic divergence
  occurs among temporal and spatial collections of
  Oregon copper rockfish
• Investigate correlation of genetic and geographic
  distance coast wide and in Oregon
• Assess significance of Cape Blanco or habitat
  discontinuity on population structure

6
Methods

• Genotypes compiled across 11 microsatellite loci
• Assignment test (Doh) to remove
  misidentifications (n5)
• GENEPOP exact tests for temporal genotypic
  differentiation no differences among years
• GENEPOP exact probability test for deviations
  from HWE
• Neah Bay
• Coos Bay

7
Coos Bay

• In initial analyses, Coos Bay Estuary (n9)
  differed from coastal Coos Bay
• FST 0.017
• p (genotypic fqs)0.001
• p (allelic fqs)lt0.001
• Estuary treated as separate population, excluded
  from outer coast analyses

8
Geographic Analyses

• F-statistics and tests for allelic and genotypic
  differentiation using GENEPOP
• Correlation between geographic and genetic
  distance using GENEPOP Mantel Tests
• Factorial correspondence analysis (FCA) using
  GENETIX
• Hierarchical AMOVA using ARLEQUIN

9
Results
10
Geographic Divergence
p lt 0.05
11
Isolation by Distance (Whole Coast)
12
Isolation by Distance (Oregon)
13
FCA Coastwide
14
FCA Oregon
15
Hierarchical AMOVA
p lt 0.05
16
Hierarchical AMOVA
p lt 0.05
17
Hierarchical AMOVA
p lt 0.05
18
Conclusions

• Significant genetic divergence at coastwide and
  fine scales relative temporal stability
• Correlation of genetic and geographic distance
  significant at coastwide scale, but not
  significant within Oregon
• Within Oregon, both habitat discontinuity and
  distance may contribute to population structure

19
Final Thoughts

• Realized dispersal may be far less than potential
  dispersal, even in species with long larval
  stages
• Habitat discontinuities may be far more important
  than oceanographic barriers in structuring
  populations

20
Acknowledgements

• Banks Lab
• Dr. Michael Banks, Dr. Mark Camara, Daniel
  Gomez-Uchida, Dave Jacobson, Kathleen OMalley,
  Mark Johnson, Isabelle Meusnier, Melina Moyer,
  Greg Moyer, Renee Bellinger, Jeremiah Bernier,
  Christie Singbusch, Jim Krenz, John Chapman
• Buonaccorsi Lab
• Dr. Vincent Buonaccorsi, Heather Hassel, Katie
  Glunt
• OSU Committee Members
• Dr. Michael Banks, Dr. Vincent Buonaccorsi, Dr.
  Stephen Palumbi, Dr. Selina Heppell, Dr. John
  Luna
• Financial Support
• Oregon SeaGrant, Hatfield Marine Science Center
  Markham First-year Student Award, Markham Award