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Regional differences in Pacific sardine populations determined by otolith morphology

Regional differences in Pacific sardine populations determined by otolith morphology. Barbara Javor, SWFSC. Pacific sardine migrations. Felix-Uraga et al., 2005. Humboldt Bay. Monterey. Pt Hueneme. San Diego. Ensenada. Gulf of CA. Bahía Magdalena. Survey collections Port & bait samples.

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Regional differences in Pacific sardine populations determined by otolith morphology

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  1. Regional differences in Pacific sardine populations determined by otolith morphology Barbara Javor, SWFSC

  2. Pacific sardine migrations Felix-Uraga et al., 2005

  3. Humboldt Bay Monterey Pt Hueneme San Diego Ensenada Gulf of CA Bahía Magdalena Survey collections Port & bait samples

  4. 4 Inter-related Otolith Research Studies • Coastwide similarities and differences in juvenile otoliths (late age-0 to age-2) • 2.Does temperature play a role? • 3. Northern vs. Southern California vs. Ensenada: year-to-year trends • 4. Offshore, adult sardine from spring surveys

  5. What can sardine otoliths tell us? • Age • Regional and temporal characteristics • Morphometric features[image analysis] • Temperature (d18O in CaCO3) [mass spec]

  6. Morphometric Analysis • Collection of >5700 otoliths from most of their range • Principal components analysis showed length, area, perimeter, andweight were the most important factors • Analysis of “Perimeter-Weight Profiles” (PWP’s) based on weight-length, perimeter-length, and perimeter-area relationships of “average” otoliths • Compared regions by age (size) and date

  7. Calculating perimeter from length or area

  8. Calculating weight from length

  9. Perimeter-weight profiles of sardine otoliths 1. Coastwide survey

  10. 2. Temperature There is a strong correlation between temperature vs. otolith perimeter and weight in the San Diego population of sardines

  11. PWP’s of age 0-1 cohorts, 2006-7: Monterey, Port Hueneme, and San Diego 3. Year-to-year trends

  12. Nearshore sardines migrate away when they reach 170-180 mm SL

  13. San Diego PWP’s appear to have shifted since 2008

  14. Since July, 2008, San Diego sardine otoliths have had similar morphological characteristics as Gulf sardine

  15. Both San Diego and Monterey sardine otoliths have had “warmer” PWP features since 2008

  16. Ensenada sardine otoliths are light and not highly lobed 96

  17. 4. Offshore adults Spring surveys, 2004 and 2009, Perimeter-Weight Profiles

  18. The relationship between otolith weight and standard length was uncoupled in offshore California sardine in 2004

  19. Conclusions from otolith morphology studies • Regional differences were found between Monterey, San Diego, and Baja California populations • Age-0 otolith PWPs may resemble those of older sardine from the same locale and cohort • Regional characteristics may change over time • San Diego sardine since mid-2008 have had characteristics of southern Baja sardine. Why? Expansion of Baja populations, temperature preferences, oceanographic conditions?

  20. Where do we go from here? • TRINATIONAL RESEARCH EFFORT: Sharing otoliths, methods, and data • FISHERMEN: Noting juvenile schools, special collections of young sardine • PORT SAMPLERS: Special set-asides of juveniles • STOCK ASSESSMENT TEAM: Is there a possible role for otolith attributes in models and predictions?

  21. Acknowledgments • Collaborators and co-authors at SWFSC • Collectors at SWFSC, NWFSC, California Fish & Game, Fisheries & Oceans (Canada), CICESE & CICIMAR (Mexico) • Everingham Bros. for monthly samples of live sardine

  22. For further reading…

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