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Introduction
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Publications
Publications (191)
To understand how turtles use the nesting habitat at Raine Island across a nesting season, and how the turtles respond to the restoration of the island’s dune systems, we identified 534 nesting events for 39 green turtles Chelonia mydas across 2 breeding seasons using data derived from satellite tags. Tracked turtles laid between 4 and 10 clutches...
The ingestion of plastic by marine turtles is now reported for all species. Small juvenile turtles (including post-hatchling and oceanic juveniles) are thought to be most at risk, due to feeding preferences and overlap with areas of high plastic abundance. Their remote and dispersed life stage, however, results in limited access and assessments. He...
Queensland Department of Environment and Science. 134 pp.
www.ausmarineturtlesymposium.com.au/proceedings/
Variation in levels of multiple paternity (MP) among species, populations and individuals has important ecological and evolutionary ramifications including maintenance of genetic diversity and offspring fitness benefits. Within species, differences in breeding experience and body size may affect the levels of MP via mate choice preferences. The pre...
Globally, tropical and subtropical regions have experienced an increased frequency and intensity in extreme weather events, ranging from severe drought to protracted rain depressions and cyclones, these coincided with an increased number of marine turtles subsequently reported stranded. This study investigated the relationship between environmental...
Vessel collision is a recognised threat to sea turtles residing in coastal waters. Although management systems (i.e. Go Slow Zones) are in place in some areas to minimise vessel-turtle collisions, incidents may persist when the spatial extent of the protection and habitat use by animals do not match or when turtle populations increase. In Queenslan...
Context
Off-shore recruitment impairment of sea-turtle hatchlings because of light pollution is a growing concern to conservation of sea-turtle population throughout the world. Studies have focussed on sea-turtle hatchling sea-finding behaviour, and ignored the possible effect that on-shore lighting might have on hatchlings after they have entered...
Home range analysis is a powerful tool for identifying priority areas for conservation, but estimating the home range for many species is still challenging. In particular, highly mobile species may use different areas at different times (e.g. summer or winter), so temporally-biased location data may only partially represent their home range. We inv...
Project prioritisation protocols are an important tool for allocating conservation resources efficiently, and have been applied to a range of species and ecosystems. Current approaches are inadequate when applied to species with distinct threats impacting different and/or multiple life history stages, such as sea turtles. We develop a model that in...
Context
It is well established that artificial light can disrupt the sea-finding ability of sea turtle hatchlings, and some manufactures are now marketing ‘turtle-friendly’ lights that are supposed to be minimally disruptive to this sea-finding behaviour. However, there have been no studies that have tested whether ‘turtle-friendly’ lights are beni...
Vulnerable species may be removed from their normal habitat and released at a new location for conservation reasons (e.g. re-establish or augment a local population) or due to difficulty or danger in returning individuals to original sites (e.g. after captivity for research or rehabilitation). Achieving the intended conservation benefits will depen...
Understanding the dietary ecology of animals provides information about their habitat requirements, facilitating informed conservation. We used last-bite diet and stable isotope analysis to assess the diet of juvenile and adult green turtles (Chelonia mydas) at two different habitats located 10 km apart within Port Curtis, Queensland, Australia. La...
Hawksbill turtle (Eretmochelys imbricata) populations have experienced global decline because of a history of intense commercial exploitation for shell and stuffed taxidermied whole animals, and harvest for eggs and meat. Improved understanding of genetic diversity and phylogeography is needed to aid conservation. In this study, we analyzed the mos...
In-water monitoring of marine vertebrates is usually expensive while the use of stranding data can be used to provide a cost-effective estimation of disease and mortality. Strandings for Queensland are recorded in a web based database (StrandNet) managed by the Queensland Government’s Department of Environment and Heritage Protection (EHP). Data re...
Biochemical and haematological parameters are increasingly used to diagnose disease in green sea turtles. Specific clinical
pathology tools, such as plasma protein electrophoresis analysis, are now being used more frequently to improve our ability
to diagnose disease in the live animal. Plasma protein reference intervals were calculated from 55 cli...
Understanding the movement patterns of an endangered population is critical for the implementation of an effective management and conservation strategy. Here we present horizontal and vertical movement for juvenile and adult green turtles (Chelonia mydas) (n=16) in the Grand Lagon Sud (GLS) of New Caledonia. We used a combination of satellite tags...
In the past two decades, stable isotope analysis (SIA) has been increasingly used to infer dietary ecology and habitat use in sea turtles. Tissue samples for SIA are often collected from adult females during a nesting event because turtles are easily accessible then. However, this sampling opportunity can be easily missed, or the female may be dist...
Effective management decisions about the conservation of threatened species often rely on good information about their biology and life-history traits. Nearly half of all turtle species face extinction in the wild through worldwide rapid declines in species abundance and habitat loss. The vulnerable western sawshelled turtle, Myuchelys bellii, from...
Despite being critically endangered, the at-sea behaviour of hawksbill turtles (Eretmochelys imbricata) remains insufficiently understood to support a global conservation strategy. Habitat location and spatial use are poorly documented, which is particularly true for the globally important Australian hawksbill population. We equipped 10 adult femal...
Migratory marine species present challenges for conservation because of complex threats within their pelagic dispersal zones, including coastal foraging areas and extensive migration pathways, or at breeding grounds. To better understand the connectivity between green turtle rookeries and foraging populations, we sequenced the mtDNA control region...
An investigation into the health of green turtles was undertaken near Gladstone, Queensland, in response to a dramatic increase in stranding numbers in the first half of 2011. A total of 56 live turtles were subject to clinical examination and blood sampling for routine blood profiles, and 12 deceased turtles underwent a thorough necropsy examinati...
Herbivorous turtle, Chelonia mydas, inhabiting the south China Sea and breeding in Peninsular Malaysia, and Natator depressus, a carnivorous turtle inhabiting the Great Barrier Reef and breeding at Curtis Island in Queensland, Australia, differ both in diet and life history. Analysis of plasma metabolites levels and six sex steroid hormones during...
Marine megafauna tend to migrate vast distances, often crossing national borders and pose a significant challenge to managers. This challenge is particularly acute in the Pacific, which contains numerous small island nations and thousands of kilometers of continental margins. The green sea turtle, Chelonia mydas, is one such megafauna that is endan...
Context:
Systematic conservation planning is increasingly used to identify priority areas for protection in marine systems. However, ecosystem-based approaches typically use density estimates as surrogates for animal presence and spatial modeling to identify areas for protection and may not take into account daily or seasonal movements of animals....
Marine turtle species consist of several genetically discrete evolutionarily significant units' (ESUs) which do not interbreed. We studied Flatback turtle (Natator depressus) hatchlings from two rookeries (Mon Repos Conservation Park and Bare Sand Island, Australia) representing two separate ESUs. Turtles from these ESUs differ in several key life...
Migratory species are known to pose a challenge for conservation strategies. Indeed, it is essential to understand the underlying ecology of a species before trying to protect it. Large seagrass habitats on the coast of the Great Lagoon South (GLS) of New Caledonia are home to resident green turtles (Chelonia mydas). This study is the first to samp...
In recent years, the use of blood chemistry as a diagnostic tool for sea turtles has been demonstrated, but much of its effectiveness relies on reference intervals. The first comprehensive blood chemistry values for healthy wild hawksbill (Eretmochelys imbricata) sea turtles are presented. Nineteen blood chemistry analytes and packed cell volume we...
Non-modal scute patterns are observed more frequently in hatchlings than in adult sea turtles, which suggests greater survival of hatchlings with the modal scute pattern. Here we compare morphological parameters and fitness correlates of hatchlings of Caretta caretta and Natator depressus with the modal scute pattern against those with non-modal sc...
Sea turtle incubation biology is tightly linked to nest thermal conditions due to the effect temperature has on hatching success, sex determination, morphology and locomotion performance. Because of this relationship between nest temperature and hatchling outcomes, global warming presents an immediate threat to many sea turtle nesting beaches throu...
Sea turtles have iteroparous reproduction, migrating periodically from foraging habitat to nesting grounds where they generally lay several clutches at regular intervals throughout a nesting season. The total length of the nesting season depends ultimately on environmental conditions that are conducive to the production of viable hatchlings, and va...
ABSTRACT: In Australia, the olive ridley sea turtle Lepidochelys olivacea has received little research attention and monitoring. The Australian populations are relatively small and their distribution is limited to remote areas in the northern part of the country. Previous global genetic studies of olive ridley populations showed that the Australian...
Effective spatial classification of freshwater biodiversity remains a worldwide conservation challenge. The isolating nature of catchment boundaries over evolutionary timescales makes them potentially important in defining natural units for biodiversity management. We sought to clarify biogeographical relationships amongst drainages within Australi...
Cold stress syndrome (CSS) is the term used to describe the range of clinical signs and chronic disease processes that can occur in Florida, USA, manatees Trichechus manatus latirostris exposed to water temperatures below 20°C for extended periods. Although no cold-related adverse events have been described in the closely related dugong Dugong dugo...
A review of the data collected over the Iast 50 years by different projects on the migration of Chelonia mydas to and from New Caledonia (n=94) indicate that 1) females nesting at D'Entrecasteaux atolls (New Caledonia) are found in feeding grounds ali along the Queensland coast up to Papua New Guinea but also in New Caledonian waters, and 2) female...
Natal dispersal of sea turtles is an energetically demanding activity that is fuelled primarily by aerobic metabolism. However, during intense exercise reptiles can use anaerobic metabolism to supplement their energy requirements. We assessed anaerobic metabolism in dispersing hatchling loggerhead and flatback turtles by measuring the concentration...
Genetic parentage studies can provide detailed insights into the mating system dynamics of wild populations, including the prevalence and patterns of multiple paternity. Multiple paternity is assumed to be common among turtles, though its prevalence varies widely between species and populations. Several important groups remain to be investigated, i...
La Roche Percée, in New Caledonia, is the most important loggerhead turtle rookery outside of Australia for the eastern Pacific genetic stock. The females nesting on this beach are genetically similar to the females found at the Mon Repos rookery in Queensland, Australia. This study shows how nest temperature affects the phenotype of genetically si...
Coastal development adjacent to sea turtle nesting beaches can result in an increase in exposure to artificial lighting at night. That lighting can repel nesting females and interfere with the orientation of hatchlings from the nest to the sea. Disrupted hatchling orientation is a serious source of turtle mortality, sufficient to reduce recruitment...
Fast acquisition GPS technologies such as Fastloc GPS have been commonly used in recent years to study fine scale spatio-temporal ecology of marine vertebrates. While Fastloc GPS gives more accurate locations than earlier methods, it remains important to identify and remove locations with high error because some location fixes are much less accurat...
Swimming performance influences the dispersal success of sea turtle hatchlings when they first enter the water and engage in a ‘swimming frenzy’ which moves them rapidly off-shore. We simultaneously measured swim thrust (in millinewtons, mN) and metabolic rate (in milliwatts, mW) of loggerhead Caretta caretta and flatback turtle Natator depressus h...
The objective of the present study was to measure the concentration of contaminants in blood of
live green turtles captured in the Boyne River estuary near Gladstone, and to evaluate whether
the contaminant levels are elevated and may pose a risk to the health of the turtle population.
During early 2011, Port Curtis experienced approximately 5 ti...
Swimming effort of hatchling sea turtles varies across species. In this study we analysed how swim thrust is produced in terms of power stroke rate, mean maximum thrust per power stroke and percentage of time spent power stroking throughout the first 18 h of swimming after entering the water, in both loggerhead and flatback turtle hatchlings and co...
Biochemical and hematological reference intervals have not previously been reported for Emydura macquarii krefftii. In 2009, 56 E. m. krefftii were captured by hand from the Burnett Catchment, clinically assessed to determine health status and blood sampled. Reference intervals were calculated from the 35 clinically healthy turtles using techniques...
Sea turtles undertake long migrations in the open ocean, during which they rely at least partly on magnetic cues for navigation. In principle, sensitivity to polarized light might be an additional sensory capability that aids navigation. Furthermore, polarization sensitivity has been linked to ultraviolet (UV) light perception which is present in s...
The objective of this study was to investigate how seasonally fluctuating environmental conditions influence the diving performance of the highly aquatic, bimodally respiring turtle Rheodytes leukops in a natural setting. Over four consecutive seasons (Austral autumn 2000 to summer 2001), the diving behaviour of adult turtles was recorded via press...
The purpose of this study was to determine whether a relationship existed between the diel surfacing trends of the bimodally respiring freshwater turtle Rheodytes leukops and daily fluctuations in specific biotic and abiotic factors: The, diel surfacing behaviour of adult R. leukops was recorded over four consecutive seasons (Austral autumn 2000 -...
Given the potential vulnerability of sea turtles to climate change, a growing number of studies are predicting how various climatic processes will affect their nesting grounds. However, these studies are limited by scale, because they predict how a single climatic process will affect sea turtles but processes are likely to occur simultaneously and...
The blood and eggs of the flatback turtle (Natator depressus) sampled when nesting at Curtis Island, Queensland, Australia. In the blood, zinc was present at the highest concentration of 151.15 ± 1.45 μg/L followed by copper (7.74 ± 0.09 μg/L). Lead was found only in some individuals. The measured trace elements in the blood were maternally transfe...
Biochemical and hematologic reference intervals have been reported for loggerhead sea turtles (Caretta caretta, Linnaeus 1758), but low sample numbers and simple statistical analyses have constrained their diagnostic usefulness. During June 2007-May 2008, 101 loggerhead sea turtles in Moreton Bay, Queensland, Australia, were captured by hand from b...
Projected sea‐level rise (SLR) is expected to cause shoreline erosion, saline intrusion into the water table and inundation and flooding of beaches and coastal areas. Areas most vulnerable to these physical impacts include small, tropical low‐lying islands, which are often key habitat for threatened and endemic species, such as sea turtles.
Success...
Causes of disease and mortality in marine turtles are frequently based on opportunistic investigations producing results that may not contribute to knowledge on how to protect their survival rate. Over a 4-year period (2006-2009), the major causes of stranding and morbidity in 100 green turtles (Chelonia mydas) from southern Queensland on the east...
Sex determination and hatching success in sea turtles is temperature dependent and as a result global warming poses a threat to sea turtles. Warmer sand temperatures may skew sea turtle population′s sex ratios towards predominantly females and decrease hatching success. Therefore, understanding the rates at which sand temperatures are likely to inc...
Sea turtles rely on reef islands for key parts of their reproductive cycle and require specific sediment characteristics to incubate their eggs and dig their nests. However, little is known about the sedimentological characteristics of sea turtle rookeries, how these sediment characteristics affect the vulnerability of rookeries to climate change,...
Coastal seagrass habitats in tropical and subtropical regions support aggregations of resident green turtles (Chelonia mydas) from several genetically distinct breeding populations. Migration of individuals to their respective dispersed breeding sites provides a complex pattern of migratory connectivity among nesting and feeding habitats of this sp...
This paper presents the first data on the diving behaviour of Flatback turtles, Natator depressus, between nesting events. Dive profiles were recorded in turtles from breeding populations at Curtis island in Queensland and at Bare Sand Island in the Northern Territory, using Time-Depth Recorders (TDRs). Both populations displayed dive types typical...
Marine turtles are generally viewed as vulnerable to climate change because of the role that temperature plays in the sex determination of embryos, their long life history, long age-to-maturity and their highly migratory nature. Extant species of marine turtles probably arose during the mid-late Jurassic period (180-150 Mya) so have survived past s...