Life history traits of the sea snake Emydocephalus annulatus , based on a 17-yr study
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Life history traits of the sea snake Emydocephalus annulatus, based on a 17-yr study Richard Shine1,2
•
Terri G. Shine1 • Gregory P. Brown1 • Claire Goiran3
Received: 5 April 2020 / Accepted: 29 June 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Although sea snakes are important predators in coral reef ecosystems and have undergone substantial population declines in some areas, we have little robust information on life histories of these animals. Based on a 17-yr mark–recapture study of turtle-headed sea snakes (Emydocephalus annulatus) in New Caledonia ([ 1200 individuals marked), we can confidently allocate ages to 539 individuals (1–11 yr of age). Using data for those snakes, we describe patterns of growth and reproduction. Using the entire data set, we also estimate annual rates of survival. One to three large offspring (300 mm snout–vent length [SVL]) are born after a prolonged (8-month) gestation. The young snakes grow rapidly until they are about 2 yr old (500 mm SVL), after which growth slows, especially in males. Most females begin reproducing at 3 yr of age, and they produce a litter (typically of two offspring) in about 2 out of every 3 or 4 yr thereafter. Annual survival rates are around 70%, but some individuals live for more than a decade.Overall, the life history of this species involves rapid growth and early maturation, followed by low but sustained reproductive output. Despite their relatively recent evolutionary origin, hydrophiine sea snakes are remarkably diverse in life histories as well as in
Topic Editor Stuart Sandin & Richard Shine [email protected] 1
Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
2
School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
3
LabEx Corail and ISEA, Universite´ de la NouvelleCale´donie, BP R4, 98851 Noume´a Cedex, New Caledonia
morphologies and diets. Hence, even closely related taxa may differ substantially in their vulnerability to threatening processes. Keywords Aipysurine Demography Elapidae Hydrophiidae Hydrophiinae
Introduction Diverse and abundant in coral reefs of the IndoPacific, sea snakes play important ecological roles as mesopredators (Reed et al. 2002; Ineich et al. 2007). Thus, rapid declines of populations of sea snakes have raised widespread concern about the conservation status of this group and the trophic consequences of their extirpation (Udyawer et al. 2018). Puzzlingly, some of those declines have occurred in areas protected from overt anthropogenic impacts (e.g. Goiran and Shine 2013; Lukoschek et al. 2013). The uncertain causation for population decline suggests that we urgently need to understand more about the life histories of sea snakes. For example, traits such as slow growth, delayed maturation and infrequent reproduction can render a population more vulnerable to threatening processes (e.g. Reed and Shine 2002; Webb et al. 2002). Unfortunately, robust information on this topic is rare for sea sna
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