title: Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic.
abstract: Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations.
authors.affiliation: Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Karen A
authors.identifier: 0000-0002-6286-1901
authors.initials: KA
authors.lastname: Bjorndal
authors.affiliation: Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Alan B
authors.initials: AB
authors.lastname: Bolten
authors.affiliation: Ecological Modelling Services Pty Ltd, University of Queensland, St Lucia, QLD, Australia.
authors.forename: Milani
authors.initials: M
authors.lastname: Chaloupka
authors.affiliation: NOAA National Marine Fisheries Service, Northeast Fisheries Science Center, Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA.
authors.forename: Vincent S
authors.initials: VS
authors.lastname: Saba
authors.affiliation: Centro TAMAR-ICMBio, CLBI - Parnamirim, Rio Grande do Norte, Brazil.
authors.forename: Cláudio
authors.initials: C
authors.lastname: Bellini
authors.affiliation: Fundação Pró TAMAR, Salvador, Bahia, Brazil.
authors.forename: Maria A G
authors.initials: MAG
authors.lastname: Marcovaldi
authors.affiliation: Fundação Pró-TAMAR, Pernambuco, Brazil.
authors.forename: Armando J B
authors.initials: AJB
authors.lastname: Santos
authors.affiliation: Fundação Pró-TAMAR, Pernambuco, Brazil.
authors.forename: Luis Felipe Wurdig
authors.initials: LFW
authors.lastname: Bortolon
authors.affiliation: Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA.|Smithsonian Tropical Research Institute, Washington, DC, USA.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Meylan
authors.affiliation: Smithsonian Tropical Research Institute, Washington, DC, USA.|Natural Sciences Collegium, Eckerd College, St. Petersburg, FL, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Meylan
authors.affiliation: Bermuda Turtle Project, Flatts, Bermuda.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gray
authors.affiliation: Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Hardy
authors.affiliation: Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Brost
authors.affiliation: Inwater Research Group, Jensen Beach, FL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Bresette
authors.affiliation: Inwater Research Group, Jensen Beach, FL, USA.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Gorham
authors.affiliation: Family Island Research and Education, Newport, RI, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Connett
authors.affiliation: Family Island Research and Education, Newport, RI, USA.
authors.forename: Barbara Van Sciver
authors.initials: BVS
authors.lastname: Crouchley
authors.affiliation: Geronimo Program, St. George's School, Newport, RI, USA.
authors.forename: Mike
authors.initials: M
authors.lastname: Dawson
authors.affiliation: Geronimo Program, St. George's School, Newport, RI, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Hayes
authors.affiliation: DRNA-PR, San Juan, Puerto Rico.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Diez
authors.affiliation: Chelonia Inc, San Juan, Puerto Rico.
authors.forename: Robert P
authors.initials: RP
authors.lastname: van Dam
authors.affiliation: Sea Turtle Conservation Bonaire, Kralendijk, Bonaire, Dutch Caribbean.
authors.forename: Sue
authors.initials: S
authors.lastname: Willis
authors.affiliation: Sea Turtle Conservation Bonaire, Kralendijk, Bonaire, Dutch Caribbean.
authors.forename: Mabel
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authors.affiliation: U.S. Geological Survey, Wetland and Aquatic Research Center, Davie, FL, USA.
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authors.initials: KM
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authors.affiliation: U.S. Geological Survey, Wetland and Aquatic Research Center, Davie, FL, USA.
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authors.initials: MS
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authors.affiliation: Cherokee Nation Technologies, NSU Center for Collaborative Research, Davie, FL, USA.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Crowder
authors.affiliation: National Park Service, Christiansted, St. Croix, Virgin Islands.
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authors.initials: C
authors.lastname: Pollock
authors.affiliation: National Park Service, Christiansted, St. Croix, Virgin Islands.
authors.forename: Zandy
authors.initials: Z
authors.lastname: Hillis-Starr
authors.affiliation: Facultad de Agronomía y Veterinaria, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Muñoz Tenería
authors.affiliation: El Colegio de la Frontera Sur -Unidad Chetumal, Chetumal, Quintana Roo, México.
authors.forename: Roberto
authors.initials: R
authors.lastname: Herrera-Pavón
authors.affiliation: Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Labrada-Martagón
authors.affiliation: Dirección de Ecología Municipio de Solidaridad, Quintana Roo, México.
authors.forename: Armando
authors.initials: A
authors.lastname: Lorences
authors.affiliation: Parque Xcaret, Municipio de Solidaridad Playa del Carmen, Quintana Roo, México.
authors.forename: Ana
authors.initials: A
authors.lastname: Negrete-Philippe
authors.affiliation: US Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, USA.
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authors.initials: MM
authors.lastname: Lamont
authors.affiliation: Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Jacksonville Field Laboratory, Jacksonville, FL, USA.
authors.forename: Allen M
authors.initials: AM
authors.lastname: Foley
authors.affiliation: Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA.
authors.forename: Rhonda
authors.initials: R
authors.lastname: Bailey
authors.affiliation: US Geological Survey, Florida Cooperative Fish and Wildlife Research Unit, Gainesville, FL, USA.
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Carthy
authors.affiliation: Florida Cooperative Fish and Wildlife Research Unit, Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA.
authors.forename: Russell
authors.initials: R
authors.lastname: Scarpino
authors.affiliation: Florida Cooperative Fish and Wildlife Research Unit, Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: McMichael
authors.affiliation: Environmental Services, Integrated Mission Support Services, Kennedy Space Center, Florida, USA.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Provancha
authors.affiliation: Cape Eleuthera Institute, Rock Sound, Eleuthera, The Bahamas.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Brooks
authors.affiliation: Fundação Pró TAMAR, Salvador, Bahia, Brazil.
authors.forename: Adriana
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authors.lastname: Jardim
authors.affiliation: Fundação Pró TAMAR, Salvador, Bahia, Brazil.
authors.forename: Milagros
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authors.lastname: López-Mendilaharsu
authors.affiliation: Karumbé, Montevideo, Uruguay.
authors.forename: Daniel
authors.initials: D
authors.lastname: González-Paredes
authors.affiliation: Karumbé, Montevideo, Uruguay.
authors.forename: Andrés
authors.initials: A
authors.lastname: Estrades
authors.affiliation: Karumbé, Montevideo, Uruguay.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Fallabrino
authors.affiliation: Karumbé, Montevideo, Uruguay.
authors.forename: Gustavo
authors.initials: G
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authors.affiliation: Karumbé, Montevideo, Uruguay.
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Vélez-Rubio
authors.affiliation: National Park Service, St. John, Virgin Islands.
authors.forename: Ralf H
authors.initials: RH
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authors.affiliation: U.S. Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit, Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA.
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authors.initials: JA
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authors.affiliation: Boca Raton, FL, USA.
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authors.affiliation: APFFLT-CONANP, Campeche, México.
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authors.lastname: Guzmán Hernández
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Stringell
authors.affiliation: Marine Conservation Society, Ross-on-Wye, Herefordshire, UK.
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authors.affiliation: Marine Conservation Society, Ross-on-Wye, Herefordshire, UK.
authors.forename: Peter B
authors.initials: PB
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authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.
authors.forename: Annette C
authors.initials: AC
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authors.affiliation: Department of Environment and Coastal Resources, National Environment Centre, Providenciales, Turks and Caicos Islands.
authors.forename: Quinton
authors.initials: Q
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authors.affiliation: The School for Field Studies, Center for Marine Resource Studies, South Caicos, Turks and Caicos Islands.
authors.forename: Marta
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authors.affiliation: Department of Environment and Coastal Resources, National Environment Centre, Providenciales, Turks and Caicos Islands.
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authors.affiliation: Texas A&M University at Galveston, Galveston, TX, USA.
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authors.affiliation: Environmental Institute of Houston, University of Houston - Clear Lake, Houston, TX, USA.
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authors.initials: AL
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authors.affiliation: Texas A&M University at Galveston, Galveston, TX, USA.
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authors.affiliation: Padre Island National Seashore, Corpus Christi, TX, USA.
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authors.affiliation: Department of Environment, Grand Cayman, Cayman Islands.
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authors.affiliation: Department of Environment, Grand Cayman, Cayman Islands.
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authors.lastname: Collyer
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.
authors.forename: Brendan J
authors.identifier: 0000-0003-3845-0034
authors.initials: BJ
authors.lastname: Godley
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.
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authors.initials: A
authors.lastname: McGowan
authors.affiliation: Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, UK.
authors.forename: Matthew J
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authors.lastname: Witt
authors.affiliation: Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Cathi L
authors.initials: CL
authors.lastname: Campbell
authors.affiliation: Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Lagueux
authors.affiliation: Hope Town, Abaco, The Bahamas.
authors.forename: Thomas L
authors.initials: TL
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authors.affiliation: Elbow Reef Lighthouse Society, Abaco, The Bahamas.
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mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D049628:Body Size; D004463:Ecology; D013696:Temperature; D014426:Turtles / Q000254:growth & development*
keywords: 
  Caretta caretta
  ; 
  Chelonia mydas
  ; 
  Eretmochelys imbricata
  ; ecological regime shifts; multivariate ENSO index; sea surface temperature; seagrass; somatic growth rates