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Pelagic interactions among temperate migratory terns , tunas and dolphins

Marie Caroline-Martin. Pelagic interactions among temperate migratory terns , tunas and dolphins. Holly F. Goyert, Lisa L. Manne, and Richard R. Veit hgoyert@gc.cuny.edu Department of Biology The City University of New York Graduate Center and College of Staten Island.

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Pelagic interactions among temperate migratory terns , tunas and dolphins

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  1. Marie Caroline-Martin Pelagic interactions among temperate migratory terns, tunas and dolphins Holly F. Goyert, Lisa L. Manne, and Richard R. Veit hgoyert@gc.cuny.edu Department of Biology The City University of New York Graduate Center and College of Staten Island Marie Caroline-Martin

  2. Habitat associations of foraging terns Do terns select particular marine habitats characterized by standard parameters? • fluorescence (primary productivity) • sea surface temperature (SST) • salinity • bathymetry (depth) • distance to shore (Powers 1984)

  3. Subsurface predator associations of foraging terns Do terns rely on facilitation* for increased prey • detectability (local enhancement) and/or • accessibility (commensal relationships)? • tunas • dolphins • whales

  4. Surveys

  5. Zero-Inflated Negative Binomial Generalized Linear Mixed Model (ZINB glmmADMB) • large (N > 10,000) due to fine scale (0.3 km2) • non-negative (count data, converted to densities) • skewed (non-normal) • overdispersed(variance >> mean) • zero-inflated (majority of low values) • robust (outliers of interest, as isolated large feeding flocks/schools) • spatially/temporally autocorrelated (nested random effect to remove interdependence)

  6. Pooled Tern Species Observed

  7. Spring and Fall ZINB GLMM models

  8. Spring

  9. Fall

  10. Spatial Auto- and Cross-Correlation

  11. Tern Behavior

  12. Habitat and subsurface predator associations of foraging terns Higher densities of terns likely: • Spring • shallower water on the New England shelf • lower salinity • lower primary productivity (Amorim et al. 2009) • higher SST; warm gulf stream eddies? • offshore earlier (inshore later for breeding) • Fall • deeper water (dispersal) • the inside edge of George’s Bank closer to shore • higher densities of both tunas and dolphins (synchrony with fall migration) • offshore earlier (migrating by October)

  13. Habitat and subsurface predator associations of foraging terns Higher densities of terns likely: • Spring • shallower water on the New England shelf • lower salinity • lower primary productivity (Amorim et al. 2009) • higher SST; warm gulf stream eddies? • offshore earlier (inshore later for breeding) • Fall • deeper water (dispersal) • the inside edge of George’s Bank closer to shore • higher densities of both tunas and dolphins (synchrony with fall migration) • offshore earlier (migrating by October)

  14. Behavioral associations Terns foragedover tunas and dolphins • response to ephemeral prey? • fine scale associations at 0.3 km2 • cross-correlations at 1-2 km patch sizes • evidence of opportunistic foraging strategy: • associate with suitable habitat until • encounter tunas and dolphins  • resort to facilitation to locate and access prey

  15. Community Implications This study provides: • original documentation of Common, Roseate, and Arctic terns statistically associating with tunas/dolphins • characterization of pelagic tern foraging habits/habitat • large spatial extent at fine-scale resolution • appropriate management of offshore wind facilities This study raises the questions: • adaptability to fluctuating changes in climate (SST)? • response to overfishing of Atlantic tuna populations?

  16. Acknowledgments Carolyn Mostello Jim Manning Andrew Gilbert Dave Fournier Hans Skaug Ben Bolker Dick Veit (Advisor) Lisa Manne Jochen Albrecht John Verzani Marie Caroline-Martin Tim White Sarah Luecke Flaherty Bryce Geyer

  17. Questions? hgoyert@gc.cuny.edu Marie Caroline-Martin

  18. Primary Productivity

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