Caretta caretta (Loggerhead turtle, North Atlantic):  

Predictions & Data for this entry

Model:  std  

MRE = 0.140
SMSE = 0.154

Zero-variate data
ah51.3 46.52 (0.09311)dage at hatching StokWyne2006, GodfMros1997
ab57.4 50.26 (0.1244)dage at birthStok2014
ap6570 4834 (0.2642)dage at pubertySpot2004
am2.446e+04 2.585e+04 (0.05697)dlife spanWiki
Lb4.5 5.539 (0.2309)cmSCL at birth ReicBjor2008, StokWyne2006
Lh4.5 5.536 (0.2303)cmSCL at hatching ReicBjor2008, StokWyne2006
Lp 80 76.79 (0.04012)cmSCL at puberty ByrdMurp2005, EhrhYode1978, Ston1980, Nort2005, TiwaBjor2000
Li105.3 94.52 (0.102)cmultimate SCL ByrdMurp2005, EhrhYode1978, Ston1980, Nort2005, TiwaBjor2000
Wwb19.41 23.55 (0.2132)gwet weight at birth ReicBjor2008, StokWyne2006
Wwh21.35 10.52 (0.5073)gwet weight at hatchingBennTapl1986
Wwp7.9e+04 6.274e+04 (0.2059)gwet weight at puberty EhrhYode1978, Nort2005
Wwi1.626e+05 1.17e+05 (0.2805)gultimate wet weight EhrhYode1978, Nort2005
E02.1e+05 2.093e+05 (0.003524)Jinitial energy content of the eggHaysSpea1991
Ri0.7671 0.8533 (0.1124)#/dmaximum reprod rate MillLimp2003, Tuck2010, SCDNR, HawkBrod2005, TiwaBjor2000
Uni-variate data
DatasetFigure(RE)Independent variableDependent variableReference
Tae see Fig. 1 (0.07999)temperatureage at emergenceStokWyne2006
tL_Stok2014_1 see Fig. 2 (0.06393)time since birthtotal lengthStok2014
tW_Stok2014_1 see Fig. 3 (0.06452)time since birthtotal wet weightStok2014
LW_Stok2014_1 see Fig. 4 (0.05736)total lengthtotal wet weightStok2014
tL_Stok2014_2 see Fig. 2 (0.06258)time since birthtotal lengthStok2014
tW_Stok2014_2 see Fig. 3 (0.1305)time since birthtotal wet weightStok2014
LW_Stok2014_2 see Fig. 4 (0.05662)total lengthtotal wet weightStok2014
tL_Stok2014_3 see Fig. 2 (0.07175)time since birthtotal lengthStok2014
tW_Stok2014_3 see Fig. 3 (0.1737)time since birthtotal wet weightStok2014
LW_Stok2014_3 see Fig. 4 (0.03885)total lengthtotal wet weightStok2014
tL_Stok2014_4 see Fig. 2 (0.07325)time since birthtotal lengthStok2014
tW_Stok2014_4 see Fig. 3 (0.1455)time since birthtotal wet weightStok2014
LW_Stok2014_4 see Fig. 4 (0.05885)total lengthtotal wet weightStok2014
tL_Stok2014_5 see Fig. 2 (0.07041)time since birthtotal lengthStok2014
tW_Stok2014_5 see Fig. 3 (0.2088)time since birthtotal wet weightStok2014
LW_Stok2014_5 see Fig. 4 (0.03909)total lengthtotal wet weightStok2014
tL_Stok2014_6 see Fig. 2 (0.02877)time since birthtotal lengthStok2014
tW_Stok2014_6 see Fig. 3 (0.1001)time since birthtotal wet weightStok2014
LW_Stok2014_6 see Fig. 4 (0.08114)total lengthtotal wet weightStok2014
tW_Park1929_1 see Fig. 5 (0.4628)time since birthtotal wet weight Park1926, Park1929
tL_Park1926 see Fig. 6 (0.03683)time since birthcarapace lengthPark1926
tW_Park1929_2 see Fig. 5 (0.4029)time since birthtotal wet weight Park1926, Park1929
tW_Park1929_3 see Fig. 5 (0.08555)time since birthtotal wet weight Park1926, Park1929
tW_Park1929_4 see Fig. 5 (0.221)time since birthtotal wet weight Park1926, Park1929
tW_HildHats1927_1 see Fig. 5 (0.1867)time since birthtotal wet weight HildHats1927
tL_HildHats1927 see Fig. 6 (0.1289)time since birthcarapace lengthHildHats1927
tW_HildHats1927_2 see Fig. 5 (0.1363)time since birthtotal wet weightHildHats1927
LW_WabnPaul2008 see Fig. 6 (0.1336)SCLwet weight WabnPaul2008
LF see Fig. 7 (0.1619)SCLeggs per clutch TiwaBjor2000
Pseudo-data at Tref
DataGeneralised animalCaretta carettaUnitDescription
v 0.02 0.07992cm/denergy conductance
kap 0.8 0.6923-allocation fraction to soma
kap_R 0.95 0.95-reproduction efficiency
p_M 18 11.77J/^3vol-spec som maint
k_J 0.002 0.0005411/dmaturity maint rate coefficient
kap_G 0.8 0.7465-growth efficiency
k 0.3 0.3606-maintenance ratio


  • Hatching can last up to 24hrs. (ref: BennTapl1986)
  • Hatching (exit the egg) to emergence (exit the nest) interval estimated as 4.1days at 30C (ref: GodfMros1997)
  • Yolk bag absorbed 24-48 hours after emerging, tissue density of 0.28 reported (ref: KraeBenn1981)
  • Onset of feeding observed in sea water (at 27 C) 2-3 days after emergence = approximated as birth (ref: Stok2014)
  • After emerging observable weight loss for the next 2-3 days (6-7 days total after hatching), connected to loss of water (ref: BennTapl1986)
  • Life stages: hatchling, pelagic juvenile, benthic juvenile, adult;switch from pelagic to benthic stage(recruitment) happens at a certain size -> 53cm SCL(min46cm SCL max64cm SCL) (ref: Bjor2000)
  • Long lived species, 11-17 yrs duration of pelagic stage, 15-35 years to reach maturity (Bjor2000; 28yrs in Spot2004, 18yrs in ZugWynn1986) (ref: Bjor2000, Spot2004, ZugWynn1986)
  • Reproduction in clutches (2-5 per reproduction season according to night watches, 3-8 according to satellite telemetry, Tuck2010) with 2-3 years remigration periods between reproduction seasons (ref: Bjor2000, Tuck2010)
  • Allocation to reproduction starts (maturity reached) before first nesting (ref: MillLimp2003)
  • Mean temperature experienced: 21.8 C, range between 18.2 and 29.2C (ref: HawkLucy2011)


  • for the Atlantic population
  • SCL = Straight Caparace Length (preferred), CCL - Curved Carapace length
  • Distinction between hatching (exit the egg shell) - emergence (exit the nest)- birth (onset of feeding).[see Facts for more details].
  • "Hatching" is added as an event with a maturity threshold E_Hh.Hatching-to-emergence period depends primarily on abiotic factors such as sand temperatureand grain size, so a "maturity level at emergence" was not introduced.
  • "Age at emergence" reported in StokWyn2006 was predicted by the model as "age at hatching",and then corrected to age at emergence (by adding the needed number of days - see predict file for details)
  • Ontogenetic habitat shift occuring mostly during the juvenile stage generally means food of better quality and higher temperature -> This was not (but can be) included in the model
  • Age at puberty reported in literature is mostly deduced from size at first nesting + bone growth marks;onset of investement into reproduction may be sooner
  • Reproduction was modeled as continous, and then approximated as clutches
  • A paper with a detailed discussion on the parameter values and model predictions: Marn et al.,2017, "Inferring physiological energetics of loggerhead turtle (Caretta caretta) from existing data using a general metabolic theory", MERE
  • In view of low somatic maintenance, pseudodata k_J = 0.002 1/d is replaced by pseudodata k = 0.3


  • [Wiki]
  • [SCDNR] South Carolina department of natural resources webpage (data for north Atlantic population).
  • [BennTapl1986] J. M. Bennett, L. E. Taplin, and G. C. Grigg. Sea water drinking as a homeostatic response to dehydration in hatchling loggerhead turtles Caretta Caretta. Comparative Biochemistry and Physiology Part A: Physiology, 83:507--513, 1986.
  • [Bjor2000] K. A. Bjorndal, A. B. Bolten, and H. R. Martins. Somatic growth model of juvenile loggerhead sea turtles Caretta caretta: duration of pelagic stage. Marine Ecology Progress Series, 202:265--272, 2000.
  • [ByrdMurp2005] J. Byrd, S. Murphy, and A. von Harten. Morphometric analysis of the northern subpopulation of Caretta caretta in South Carolina, USA. Marine Turtle Newsletter, 107:1--4, 2005.
  • [EhrhYode1978] L. M. Ehrhart and R. G. Yoder. Marine turtles of merritt island national wildlife refuge, kennedy space center, florida. In G. E. Henderson, editor, Proceedings of the Florida and interregional conference on sea turtles, July 1976, Jensen Beach, Florida, USA, volume 33 of Florida Marine Research Publication, pages 24--25. St. Petersburg : Florida Dept. of Natural Resources, Marine Research Laboratory, 1978.
  • [GodfMros1997] M. H. Godfrey and N. Mrosovsky. Estimating the time between hatching of sea turtles and their emergence from the nest. Chelonian Conservation and Biology, 2:581--585, 1997.
  • [HawkBrod2005] L. A. Hawkes, A. C. Broderick, M.H. Godfrey, and B. J. Godley. Status of nesting loggerhead turtles Caretta caretta at Bald Head Island (North Carolina, USA) after 24 years of intensive monitoring and conservation. Oryx, 39:65--72, 2005.
  • [HawkLucy2011] L. A. Hawkes, M. J. Witt, A. C. Broderick, J. W. Coker, M. S. Coyne, M. Dodd, M. G. Frick, M. H. Godfrey, D. B. Griffin, S. R. Murphy, T. M. Murphy, K. L. Williams, and B. J. Godley. Home on the range: spatial ecology of loggerhead turtles in atlantic waters of the USA. Diversity and Distributions, 17:624--640, 2011.
  • [HaysSpea1991] G. C. Hays and J. R. Speakman. Reproductive investment and optimum clutch size of loggerhead sea turtles (Caretta caretta). Journal of Animal Ecology, 60(2):455--462, Jun 1991.
  • [HildHats1927] S. F. Hildebrand and C. Hatsel. On the growth, care and behavior of loggerhead turtles in captivity. Proceedings of the National Academy of Sciences of the United States of America, 13(6):374--377, 1927.
  • [Kooy2010] S.A.L.M. Kooijman. Dynamic Energy Budget theory for metabolic organisation. Cambridge Univ. Press, Cambridge, 2010.
  • [KraeBenn1981] J. E. Kraemer and S. H. Bennett. Utilization of posthatching yolk in loggerhead sea turtles, Caretta caretta. Copeia, 2:406--411, 1981.
  • [MillLimp2003] J. D. Miller, C. L. Limpus, and M. H. Godfrey. Nest site selection, oviposition, eggs, development, hatching, and emergence of loggerhead sea turtles. In A.B. Bolten and B.E. Witherington, editors, Ecology and Conservation of Loggerhead Sea Turtles, pages 125--143. University Press of Florida, Gainesville, Florida, 2003.
  • [Nort2005] T. M. Norton. Sea turtle conservation in georgia and an overview of the Georgia sea turtle center on Jekyll Island, Georgia. Georgia Journal of Science, 63:287--289, 2005.
  • [Park1926] G. H. Parker. The growth of turtles. Proceedings of the National Academy of Sciences, 12(7):422--424, 1926.
  • [Park1929] G. H. Parker. The growth of the loggerhead turtle. The American Naturalist, 63(687):367--373, 1929.
  • [ReicBjor2008] K. J. Reich, K. A. Bjorndal, and C. Martinez del Rio. Effects of growth and tissue type on the kinetics of 13c and 15n incorporation in a rapidly growing ectotherm. Oecologia, 155:651--663, 2008.
  • [Spot2004] J. R. Spotila. Sea Turtles: A Complete Guide to their Biology, Behavior, and Conservation. The Johns Hopkins University Press and Oakwood Arts., Baltimore, Maryland, 2004.
  • [Stok2014] L Stokes. personal communication, 2014.
  • [StokWyne2006] L. Stokes, J. Wyneken, L. B. Crowder, and J. Marsh. The influence of temporal and spatial origin on size and early growth rates in captive loggerhead sea turtles (Caretta caretta) in the United States. Herpetological Conservation and Biology, 1:71--80, 2006.
  • [Ston1980] D. L. Stoneburner. Body depth: An indicator of morphological variation among nesting groups of adult loggerhead sea turtles (Caretta caretta). Journal of Herpetology, 14(2):205--206, 1980.
  • [TiwaBjor2000] M. Tiwari and K. A. Bjorndal. Variation in morphology and reproduction in loggerheads, Caretta caretta, nesting in the United States, Brazil, and Greece. Herpetologica, 56(3):343--356, 2000.
  • [Tuck2010] A. D. Tucker. Nest site fidelity and clutch frequency of loggerhead turtles are better elucidated by satellite telemetry than by nocturnal tagging efforts: Implications for stock estimation. Journal of Experimental Marine Biology and Ecology, 383:48--55, 2010.
  • [WabnPaul2008] C. Wabnitz and D. Pauly. Length-weight relationships and additional growth parameters for sea turtles. In M. L. D. Palomares and D. Pauly, editors, Von Bertalanffy growth parameters of non-fish marine organisms, volume 16 of Fisheries centre research report, page 138. Univ of British Columbia, 2008.
  • [ZugWynn1986] G. R. Zug, A. H. Wynn, and C. Ruckdeschel. Age determination of loggerhead sea turtles, Caretta caretta, by incremental growth marks in the skeleton. Smithsonian Contributions to Zoology, 427:1--34, 1986.

Bibtex files with references for this entry

Nina Marn, 2016/01/22 (last modified by Bas Kooijman 2017/11/12)

accepted: 2017/11/12

refer to this entry as: AmP Caretta caretta version 2017/11/12