Somatic growth dynamics of West Atlantic hawksbill sea turtles: a spatio‐temporal perspective

• DOI: 10.1002/ecs2.1279
• Publication Date: 2016-06-06T14:53:36Z
• Authors: Karen A. Bjorndal; Milani Chaloupka; Vincent S. Saba; Carlos E. Diez; Robert P. van Dam; Barry H. Krueger; Julia A. Horrocks; Armando J. B. Santos; Cláudio Bellini; Maria A. G. Marco...; Mabel Nava; Sue Willis; Brendan J. Godley; Shannon Gore; Lucy A. Hawkes; Andrew McGowan; Matthew J. Witt; Thomas B. Stringell; Amdeep Sanghera; Peter B. Richardson; Annette C. Broderick; Quinton Phillips; Marta C. Calosso; John A. B. Claydon; Janice Blumenthal; Felix Moncada; Gonzalo Nodarse; Yosvani Medina; Stephen G. Dunbar; Lawrence D. Wood; Cynthia J. Lagueux; Cathi L. Campbell; Anne B. Meylan; Peter A. Meylan; Virginia R. Burns...; Robin A. Coleman; Samantha Strindberg; Vicente Guzmán‐H.; Kristen M. Hart; Michael S. Cherkiss; Zandy Hillis‐Starr; Ian F. Lundgren; Ralf H. Boulon; Stephen Connett; Mark E. Outerbridge; Alan B. Bolten
• Keywords: 0106 biological sciences; Coral reefs; Reef; Sea surface temperature; 551; Oceanography; 01 natural sciences; 1105 Ecology; sea surface temperature; marine turtles; Climate change; Foraging; QH540-549.5; climate effects; Global and Planetary Change; Ecology; Geography; Geology; Climate effects; Coral reef; Habitat; West Atlantic; Physical Sciences; Avian Ecology and Climate Change Impacts; Habitat Fragmentation; coral reefs; 570; Marine turtles; Evolution; Multivariate ENSO index; Environmental science; Meteorology; Behavior and Systematics; Greater Caribbean; 14. Life underwater; Biology; Nature and Landscape Conservation; Somatic growth rates; Conservation and Management of Marine Turtles Worldwide; FOS: Earth and related environmental sciences; 15. Life on land; Global Amphibian Declines and Extinctions; 13. Climate action; Eretmochelys imbricata; FOS: Biological sciences; Environmental Science; somatic growth rates; multivariate ENSO index; Coral; 2303 Ecology

AbstractSomatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long‐lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio‐temporal effects on hawksbill growth dynamics over a 33‐yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio‐temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region‐wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0‐ or 1‐yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs.