Influence of nest temperature on morphology of Leatherback Turtle (Dermochelys coriacea) hatchlings incubated in hatcheries in Oaxaca, Mexico.

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From: Canadian Journal of Zoology(Vol. 99, Issue 5)
Publisher: NRC Research Press
Document Type: Report
Length: 7,240 words
Lexile Measure: 1460L

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Abstract :

The influence of nest incubation temperatures on carapace shape and morphological traits of Leatherback Turtle (Dermochelys coriacea (Vandelli, 1761)) hatchlings incubated in two hatcheries in Oaxaca, Mexico, was evaluated. This study was carried out from October 2016 through May 2017. On each beach, there are community groups consisting of volunteers not affiliated with universities who protect and relocate the nests to increase hatching success. In each translocated nest, a data logger was placed in the centre of the egg mass. Hatchlings were collected as they emerged from each nest. The carapaces of the hatchlings were photographed and subjected to geometric morphometric analysis; also, hatchlings were weighed and their bodies measured. The mean temperature of 12 nests in each hatchery was recorded, with no significant differences between hatcheries. The principal component analysis revealed an overlapping of the carapace shape under different temperature durations. Temperature had a significant influence on hatchling morphology. Higher mean incubation temperatures produced hatchlings with low mass, smaller appendages, narrower carapace widths, and shorter flipper lengths. Lower mean incubation temperatures produced hatchlings with greater mass, wider appendage widths, wider carapace widths, and longer flipper lengths. Results indicate that the Leatherback hatchlings incubated in hatcheries demonstrate morphology that varies in relation to nest incubation temperature in a similar way to hatchlings produced in natural environments. Key words: carapace, Dermochelys coriacea, hatchery, hatchlings, incubation, Leatherback Turtle, morphology. L'influence de la temperature d'incubation dans le nid sur la forme de la carapace et des caracteres morphologiques de petits nouvellement eclos de tortues luths (Dermochelys coriacea (Vandelli, 1761)) incubes dans deux ecloseries de Oaxaca (Mexique) a ete evaluee. L'etude a ete menee d'octobre 2016 a mai 2017. Sur chaque plage, des groupes communautaires composes de benevoles sans association a des universites protegent et deplacent les nids pour en accroitre le succes d'eclosion. Un enregistreur de donnees a ete place au centre de la masse d'oeufs dans chaque nid. Les petits etaient recueillis a leur emergence du nid. Les carapaces des petits ont ete photographiees et ont fait l'objet d'une analyse morphometrique geometrique; aussi, les petits ont ete peses et leurs corps ont ete mesures. La temperature moyenne de 12 nids dans chaque ecloserie a ete enregistree, aucune difference significative n'etant relevee entre les ecloseries. L'analyse en composantes principales revele un chevauchement de la forme des carapaces pour differentes durees de temperatures. La temperature a eu une influence significative sur la morphologie des petits. Des temperatures d'incubation moyennes plus elevees ont produit des petits de faible masse presentant des appendices plus petits, des carapaces plus etroites et des nageoires plus courtes. De faibles temperatures d'incubation moyennes ont produit des petits de plus grande masse, presentant des appendices et des carapaces plus larges et de plus longues nageoires. Les resultats indiquent que la morphologie des petits nouvellement eclos de tortues luths incubes en ecloseries varie en fonction de la temperature d'incubation du nid, a l'instar de celle des petits issus de milieux naturels. [Traduit par la Redaction] Mots-cles : carapace, Dermochelys coriacea, ecloserie, petits nouvellement eclos, incubation, tortue luth, morphologie.

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Gale Document Number: GALE|A666204559