ABSTRACT This article presents original research to investigate the relationship between integume... more ABSTRACT This article presents original research to investigate the relationship between integumentary composition and predictive thermal capacity. The authors suggest that cold stress syndrome (CSS) is unlikely to occur in dugongs, a claim that is at odds with a recent study from our group where we described the local appearance of mortality cases consistent with this syndrome. Horgan et al. (2014) made two statements, in particular, which disregarded a diagnosis following observations by specialist veterinary pathologists, yet without, to our knowledge, accessing the material themselves and instead quoting ‘unpublished data’ to support their conclusions. Further, and importantly, Horgan et al. (2014) ignore the pathological changes we described in other organ systems, which were consistent with changes noted during CSS in manatees and led to our diagnosis.Cold stress syndrome is an incompletely understood but clearly very complicated, multisystemic entity that has been described as affecting ...
Biochemical and haematological reference intervals (RIs) have been reported for sea turtles, but ... more Biochemical and haematological reference intervals (RIs) have been reported for sea turtles, but their value for ante-mortem disease diagnosis may be limited due to small sample sizes and outdated statistical analyses. In the present study, 290 green sea turtles (Chelonia mydas) were captured, clinically assessed and blood sampled. Of these, 211 were classified as 'clinically healthy' and 25 as 'clinically unhealthy'. RIs were estimated using data from the healthy turtles and compared with blood values from the unhealthy animals. All of the unhealthy animals had plasma biochemical and haematological values outside one or more RIs (albumin, 48% of unhealthy animals; alkaline phosphatase, 35%; aspartate transaminase, 13%; creatinine, 30%; globulin, 3%; glucose, 34%; lactic dehydrogenase, 26%; phosphorus, 22%; sodium, 13%; thrombocytes, 57%; and monocytes, 5%). Among small immature turtles, those with Chelonibia testudinaria plastron barnacle counts P20 were three times more likely to be unhealthy than those with no barnacles. In addition, small immature and mature turtles were more likely to be unhealthy than large immature turtles.
Biochemical and hematologic reference intervals have been reported for loggerhead sea turtles (Ca... more 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 boats; clinically assessed to determine health status; blood was sampled; and biochemical and hematologic variables were measured. Of these turtles, 66 were classified as clinically healthy and 23 as unhealthy. Reference intervals were calculated using data from clinically healthy turtles. Of the clinically unhealthy turtles, 82 and 45% had at least one biochemical and hematologic result, respectively, outside of at least one of the calculated intervals. However, only low proportions of unhealthy loggerhead sea turtles had abnormal results for each variable. The highest percentage of unhealthy turtles that were outside at least one estimated reference interval was 35%, for thrombocyte counts. Neither sex nor maturity category (mature versus large immature) influenced the risk of being clinically unhealthy. These are the first plasma biochemical and hematologic reference intervals reported for loggerhead sea turtles from the southwestern Pacific Ocean. We conclude that, for loggerhead sea turtles in Moreton Bay, separate reference intervals are required for mature and immature turtles for thrombocyte counts and for male and female turtles for lymphocyte, heterophil, and total white cell counts; otherwise, a single reference interval can be used regardless of age or sex. When estimating reference intervals in loggerhead sea turtles, it is desirable to use both methods for calculating reference intervals used in this study because intervals can differ substantially between methods for some variables. Joint interpretation using reference intervals from both methods allows the categorization of results as ''normal,'' ''suspect,'' or ''abnormal.''
Causes of disease and mortality in marine turtles are frequently based on opportunistic investiga... more 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 coast of Australia were determined by comprehensive postmortem examination. Lesions were characterized for analysis using descriptive and probability statistics. Spirorchiid parasitism was found to be the most frequently occurring cause of mortality (41.8%), followed by gastrointestinal impaction (11.8%), microbiological infectious diseases (5.2%), and trauma (5.2%). Spirorchiid parasitism with associated inflammation (75%) was the most frequently occurring disease, followed by gastrointestinal impaction (5.1%). All other diseases were observed at a low prevalence. Assessment of the likelihood of disease being influenced by risk factors (season, maturity, and gender) showed that: (i) there were more observed cases of spirorchiid infection in summer when compared with the other seasons (P = 0.029); (ii) immature turtles had more severe spirorchiid parasite infections than mature turtles (P = 0.032); and (iii) respiratory disorders were more likely (P = 0.01) in summer and autumn than winter or spring. Number of observed cases and severity of spirorchiid lesions were highest in the brain compared with other histologically examined organ systems (all P > 0.1). Further investigation is required to build on these findings, aid management decisions, and determine the significance of these diseases for green turtle survivorship in Queensland.
Biochemical and hematological reference intervals have not previously been reported for Emydura m... more 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 established in other chelonid species. Aberrant blood results were identified from the 21 clinically unhealthy turtles. Low numbers of observed cases of creatine kinase, glucose, magnesium, phosphorus and uric acid outside of the blood biochemistry reference interval were recorded, as were high numbers of observed cases of estimated eosinophils, thrombocytes and total leukocyte counts outside of the hematological reference interval. Lesions of the shell and plastron (shell rot) were observed in 38% (21/56) of the examined healthy and unhealthy turtles. Microbiological assessment of a subsample (n = 7) of these lesions grew Aeromonas veronii 100% (7/7), Aeromonas hydrophila 29% (2/7) and Acinetobacter baumannii 14% (1/7). Of the examined turtles, 13% (7/56) had evidence of opacity of the lens or anterior chamber of the eye and 70% (39/56) had erythema of the neck, axillary and inguinal soft tissues. Not all observed cases of erythema were associated with clinical ill-health. The anomalous blood results and clinical findings identified in this study suggest disease processes which may have resulted from causative agents in the surrounding environment.
In recent years, genetic studies have been used to investigate mating systems of marine turtles, ... more In recent years, genetic studies have been used to investigate mating systems of marine turtles, but to date no such research has been conducted on the flatback turtle (Natator depressus). This study investigates paternity of flatback turtle clutches at two rookeries in Queensland, Australia; Peak Island (Keppel Bay), and Mon Repos (Bundaberg). In the 2004–2005 nesting season, tissue samples were taken from either single or multiple clutches (n = 16) of nesting females (n = 8) representing a sampling effort ranging from 25% to 50% offspring per nest. Determination of the extent of multiple paternity was done using a comparative approach that included initial inferences based on observed alleles, Chi-square tests for deviations from Mendelian expectations, and three software programs (PARENTAGE1.0, GERUD2.0 and MER3.0). Results varied depending on the approach, but by calculating a consensus value of the output from these different methods, the null hypothesis of single paternity could be rejected in at least 11 of the 16 clutches (69%). Multiple paternity was thus observed in the clutches of six of nine females (67%), with two or three fathers being the most likely outcome. Analyses of successive clutches illustrated that paternal contribution to clutch fertilization can vary through time, as observed for two females. This first evidence regarding the mating system of flatback turtles indicates that multiple paternity is common in this species and that the observed frequency of multiple paternity is among the higher values reported in marine turtle species. Application of these results to estimates of effective population size (N e) suggests that population size may have been relatively stable over long periods. Continued monitoring of population dynamics is recommended to ensure that future changes in the east coast can be detected.
Journal of Veterinary Diagnostic Investigation, 2009
Over the past few decades, there have been increasing numbers of reports of diseases in marine tu... more Over the past few decades, there have been increasing numbers of reports of diseases in marine turtles. Furthermore, in recent years, there have been documented instances of apparently new diseases emerging in these species of which the etiology and/or pathogenesis remain unknown. These instances i) raise concern for the survival of marine turtles, and ii) question the health and stability of the benthic marine environments in which turtles live. Knowledge of common disease processes and pathologic changes in lesions, along with a standardized approach to postmortem and sample collection are required to document and understand the host-agent-environment interactions in marine turtle health. This review combines, for the first time, a standardized approach to the postmortem of marine turtles for veterinary clinicians, with a concurrent descriptive review of the gross and microscopic pathologic changes in lesions commonly seen.
Journal of Veterinary Diagnostic Investigation, 2009
Over the past few decades, there have been increasing numbers of reports of diseases in marine tu... more Over the past few decades, there have been increasing numbers of reports of diseases in marine turtles. Furthermore, in recent years, there have been documented instances of apparently new diseases emerging in these species of which the etiology and/or pathogenesis remain unknown. These instances i) raise concern for the survival of marine turtles, and ii) question the health and stability of the benthic marine environments in which turtles live. Knowledge of common disease processes and pathologic changes in lesions, along with a standardized approach to postmortem and sample collection are required to document and understand the host-agent-environment interactions in marine turtle health. This review combines, for the first time, a standardized approach to the postmortem of marine turtles for veterinary clinicians, with a concurrent descriptive review of the gross and microscopic pathologic changes in lesions commonly seen.
Cold stress syndrome (CSS) is the term used to describe the range of clinical signs and chronic d... more 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 coldrelated adverse events have been described in the closely related dugong Dugong dugon thus far, it has been established that they make movements in response to water temperatures lower than about 17 to 18°C. In this study, archive reports for dugong carcasses submitted to The University of Queensland School of Veterinary Science for post mortem examination during 2010 to 2012 were examined. These animals had been recovered from Moreton Bay, southeast Queensland, Australia, and 10 out of 14 fulfilled the criteria for 'potential cold stress cases.' Epidermal hyperplasia and secondary bacterial infection, serous atrophy of pericardial adipose tissue, and multisystem abscessation were features commonly noted in these cases. Water temperature data were correlated with the time of year that carcasses were submitted for examination. Higher numbers of carcasses diagnosed with potential CSS were noted during sustained periods in which water temperature was below 20°C. Given the pattern of increased submission of non-specifically, chronically unwell animals in the colder months and evidence that environmental conditions known to precipitate CSS occur in southeast Queensland, it is probable that, like manatees, dugongs in this area are affected by CSS. Further investigation to confirm and to better characterize the syndrome is recommended to refine management practices and improve treatment of affected animals.
Descriptions of the developmental stages of embryonic marine turtles are presented in the form of... more Descriptions of the developmental stages of embryonic marine turtles are presented in the form of a dichotomous key supported by drawings to facilitate identifying stages of development in the field. The key emphasizes the sequential appearance or loss of external morphological structures that can be seen either with the unaided eye or with a 310 hand lens and a handheld light. Stages are placed in the context of normal beach temperatures to facilitate estimation of laying date, emergence date, and events that cause embryonic mortality. Measurements of embryos are presented to assist determining stage.
• The broad aim of this project is to identify Management Units (MU) as the focal point for regio... more • The broad aim of this project is to identify Management Units (MU) as the focal point for regional management, with particular emphasis on Southeast Asia, but drawing also on broader studies through the Indo-Pacific. In this report we focus on results from analysis of green turtles in Southeast Asian and Western Pacific region, including samples from breeding and feeding populations and also major regional harvests. • We screened 670 nesting turtles from 27 breeding aggregations throughout Southeast Asia and the Western Pacific and 339 turtles from 3 feeding populations and 2 harvests in northern Australia, Papua New Guinea and Indonesia. These samples were assayed for variation in mitochondrial DNA (mtDNA) using gradient gel and sequencing methods. • We have identified 25 mtDNA variants shared among several rookeries with each rookery typically being characterised by a subset of 3-4 mtDNA variants. • A characteristic feature of green turtles in this region is strong divergence in frequencies of variants among breeding aggregations despite the widespread distribution of, and close relationships among many variants. • Based on evidence for significant genetic divergence we recognise the following 17 genetically discrete breeding units (Management Units) in the South East Asian and Western Pacific region:
Globally, tropical and subtropical regions have experienced an increased frequency and intensity ... more 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 variables and marine turtle stranding. The environmental variables examined in this study, in descending order of importance, were freshwater discharge, monthly mean maximum and minimum air temperatures, monthly average daily diurnal air temperature difference and rainfall for the latitudinal hotspots (-27˚,-25˚,-23˚,-19˚) along the Queensland coast as well as for major embayments within these blocks. This study found that marine turtle strandings can be linked to these environmental variables at different lag times (3-12 months), and that cumulative (months added together for maximum lag) and non-cumulative (single month only) effects cause different responses. Different latitudes also showed different responses of marine turtle strandings, both in response direction and timing.Cumulative effects of freshwater discharge in all latitudes resulted in increased strandings 10-12 months later. For latitudes-27˚,-25˚and-23˚non-cumulative effects for discharge resulted in increased strandings 7-12 months later. Latitude-19˚had different results for the noncumulative bay with strandings reported earlier (3-6 months). Monthly mean maximum and minimum air temperatures, monthly average daily diurnal air temperature difference and rainfall had varying results for each examined latitude. This study will allow first responders and resource managers to be better equipped to deal with increased marine turtle stranding rates following extreme weather events.
The ability of individuals to actively control their movements, especially during the early life ... more The ability of individuals to actively control their movements, especially during the early life stages, can significantly influence the distribution of their population. Most marine turtle species develop oceanic foraging habitats during different life stages. However, flatback turtles (Natator depressus) are endemic to Australia and are the only marine turtle species with an exclusive neritic development. To explain the lack of oceanic dispersal of this species, we predicted the dispersal of post-hatchlings in the Great Barrier Reef (GBR), Australia, using oceanographic advection-dispersal models. We included directional swimming in our models and calibrated them against the observed distribution of post-hatchling and adult turtles. We simulated the dispersal of green and loggerhead turtles since they also breed in the same region. Our study suggests that the neritic distribution of flatback post-hatchlings is favoured by the inshore distribution of nesting beaches, the local wate...
The problem of how to protect sea turtle nests from terrestrial predators is of worldwide concern... more The problem of how to protect sea turtle nests from terrestrial predators is of worldwide concern. On Queensland's southern Sunshine Coast, depredation of turtle nests by the introduced European red fox (Vulpes vulpes) has been recorded as the primary terrestrial cause of egg and hatchling mortality. We investigated the impact of foxes on the nests of the loggerhead turtle (Caretta caretta) and occasional green turtle (Chelonia mydas) over ten nesting seasons. Meshing of nests with fox exclusion devices (FEDs) was undertaken in all years accompanied by lethal fox control in the first five-year period, but not in the second five-year period. Lethal fox control was undertaken in the study area from 2005 to February 2010, but foxes still breached 27% (range19-52%) of turtle nests. In the second five-year period, despite the absence of lethal fox control, the average percentage of nests breached was less than 3% (range 0-4%). Comparison of clutch depredation rates in the two five-year periods demonstrated that continuous nest meshing may be more effective than lethal fox control in mitigating the impact of foxes on turtle nests. In the absence of unlimited resources available for the eradication of exotic predators, the use of FEDs and the support and resourcing of a dedicated volunteer base can be considered an effective turtle conservation tool on some beaches.
Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual ... more Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual animals, serves to educate the public, and contributes to conservation. We examined the outcome from rehabilitation, time in rehabilitation, and subsequent recapture and restranding rates of stranded marine turtles between 1996 and 2013 to determine if the benefits associated with this practice are cost-effective as a conservation tool. Of 13,854 marine turtles reported as stranded during this 18-year period, 5,022 of these turtles were stranded alive with the remainder verified as dead or of unknown condition. A total of 2,970 (59%) of these live strandings were transported to a rehabilitation facility. Overall, 1,173/2,970 (39%) turtles were released over 18 years, 101 of which were recaptured: 77 reported as restrandings (20 dead, 13 alive subsequently died, 11 alive subsequently euthanized, 33 alive) and 24 recaptured during normal marine turtle population monitoring or fishing activ...
NOTE Papers published in this volume and in all previous volumes of the Memoirs of the Queensland... more NOTE Papers published in this volume and in all previous volumes of the Memoirs of the Queensland Museummay be reproduced for scientific research, individual study or other educational purposes. Properly acknowledged quotations may be made but queries regarding the ...
ABSTRACT This article presents original research to investigate the relationship between integume... more ABSTRACT This article presents original research to investigate the relationship between integumentary composition and predictive thermal capacity. The authors suggest that cold stress syndrome (CSS) is unlikely to occur in dugongs, a claim that is at odds with a recent study from our group where we described the local appearance of mortality cases consistent with this syndrome. Horgan et al. (2014) made two statements, in particular, which disregarded a diagnosis following observations by specialist veterinary pathologists, yet without, to our knowledge, accessing the material themselves and instead quoting ‘unpublished data’ to support their conclusions. Further, and importantly, Horgan et al. (2014) ignore the pathological changes we described in other organ systems, which were consistent with changes noted during CSS in manatees and led to our diagnosis.Cold stress syndrome is an incompletely understood but clearly very complicated, multisystemic entity that has been described as affecting ...
Biochemical and haematological reference intervals (RIs) have been reported for sea turtles, but ... more Biochemical and haematological reference intervals (RIs) have been reported for sea turtles, but their value for ante-mortem disease diagnosis may be limited due to small sample sizes and outdated statistical analyses. In the present study, 290 green sea turtles (Chelonia mydas) were captured, clinically assessed and blood sampled. Of these, 211 were classified as 'clinically healthy' and 25 as 'clinically unhealthy'. RIs were estimated using data from the healthy turtles and compared with blood values from the unhealthy animals. All of the unhealthy animals had plasma biochemical and haematological values outside one or more RIs (albumin, 48% of unhealthy animals; alkaline phosphatase, 35%; aspartate transaminase, 13%; creatinine, 30%; globulin, 3%; glucose, 34%; lactic dehydrogenase, 26%; phosphorus, 22%; sodium, 13%; thrombocytes, 57%; and monocytes, 5%). Among small immature turtles, those with Chelonibia testudinaria plastron barnacle counts P20 were three times more likely to be unhealthy than those with no barnacles. In addition, small immature and mature turtles were more likely to be unhealthy than large immature turtles.
Biochemical and hematologic reference intervals have been reported for loggerhead sea turtles (Ca... more 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 boats; clinically assessed to determine health status; blood was sampled; and biochemical and hematologic variables were measured. Of these turtles, 66 were classified as clinically healthy and 23 as unhealthy. Reference intervals were calculated using data from clinically healthy turtles. Of the clinically unhealthy turtles, 82 and 45% had at least one biochemical and hematologic result, respectively, outside of at least one of the calculated intervals. However, only low proportions of unhealthy loggerhead sea turtles had abnormal results for each variable. The highest percentage of unhealthy turtles that were outside at least one estimated reference interval was 35%, for thrombocyte counts. Neither sex nor maturity category (mature versus large immature) influenced the risk of being clinically unhealthy. These are the first plasma biochemical and hematologic reference intervals reported for loggerhead sea turtles from the southwestern Pacific Ocean. We conclude that, for loggerhead sea turtles in Moreton Bay, separate reference intervals are required for mature and immature turtles for thrombocyte counts and for male and female turtles for lymphocyte, heterophil, and total white cell counts; otherwise, a single reference interval can be used regardless of age or sex. When estimating reference intervals in loggerhead sea turtles, it is desirable to use both methods for calculating reference intervals used in this study because intervals can differ substantially between methods for some variables. Joint interpretation using reference intervals from both methods allows the categorization of results as ''normal,'' ''suspect,'' or ''abnormal.''
Causes of disease and mortality in marine turtles are frequently based on opportunistic investiga... more 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 coast of Australia were determined by comprehensive postmortem examination. Lesions were characterized for analysis using descriptive and probability statistics. Spirorchiid parasitism was found to be the most frequently occurring cause of mortality (41.8%), followed by gastrointestinal impaction (11.8%), microbiological infectious diseases (5.2%), and trauma (5.2%). Spirorchiid parasitism with associated inflammation (75%) was the most frequently occurring disease, followed by gastrointestinal impaction (5.1%). All other diseases were observed at a low prevalence. Assessment of the likelihood of disease being influenced by risk factors (season, maturity, and gender) showed that: (i) there were more observed cases of spirorchiid infection in summer when compared with the other seasons (P = 0.029); (ii) immature turtles had more severe spirorchiid parasite infections than mature turtles (P = 0.032); and (iii) respiratory disorders were more likely (P = 0.01) in summer and autumn than winter or spring. Number of observed cases and severity of spirorchiid lesions were highest in the brain compared with other histologically examined organ systems (all P > 0.1). Further investigation is required to build on these findings, aid management decisions, and determine the significance of these diseases for green turtle survivorship in Queensland.
Biochemical and hematological reference intervals have not previously been reported for Emydura m... more 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 established in other chelonid species. Aberrant blood results were identified from the 21 clinically unhealthy turtles. Low numbers of observed cases of creatine kinase, glucose, magnesium, phosphorus and uric acid outside of the blood biochemistry reference interval were recorded, as were high numbers of observed cases of estimated eosinophils, thrombocytes and total leukocyte counts outside of the hematological reference interval. Lesions of the shell and plastron (shell rot) were observed in 38% (21/56) of the examined healthy and unhealthy turtles. Microbiological assessment of a subsample (n = 7) of these lesions grew Aeromonas veronii 100% (7/7), Aeromonas hydrophila 29% (2/7) and Acinetobacter baumannii 14% (1/7). Of the examined turtles, 13% (7/56) had evidence of opacity of the lens or anterior chamber of the eye and 70% (39/56) had erythema of the neck, axillary and inguinal soft tissues. Not all observed cases of erythema were associated with clinical ill-health. The anomalous blood results and clinical findings identified in this study suggest disease processes which may have resulted from causative agents in the surrounding environment.
In recent years, genetic studies have been used to investigate mating systems of marine turtles, ... more In recent years, genetic studies have been used to investigate mating systems of marine turtles, but to date no such research has been conducted on the flatback turtle (Natator depressus). This study investigates paternity of flatback turtle clutches at two rookeries in Queensland, Australia; Peak Island (Keppel Bay), and Mon Repos (Bundaberg). In the 2004–2005 nesting season, tissue samples were taken from either single or multiple clutches (n = 16) of nesting females (n = 8) representing a sampling effort ranging from 25% to 50% offspring per nest. Determination of the extent of multiple paternity was done using a comparative approach that included initial inferences based on observed alleles, Chi-square tests for deviations from Mendelian expectations, and three software programs (PARENTAGE1.0, GERUD2.0 and MER3.0). Results varied depending on the approach, but by calculating a consensus value of the output from these different methods, the null hypothesis of single paternity could be rejected in at least 11 of the 16 clutches (69%). Multiple paternity was thus observed in the clutches of six of nine females (67%), with two or three fathers being the most likely outcome. Analyses of successive clutches illustrated that paternal contribution to clutch fertilization can vary through time, as observed for two females. This first evidence regarding the mating system of flatback turtles indicates that multiple paternity is common in this species and that the observed frequency of multiple paternity is among the higher values reported in marine turtle species. Application of these results to estimates of effective population size (N e) suggests that population size may have been relatively stable over long periods. Continued monitoring of population dynamics is recommended to ensure that future changes in the east coast can be detected.
Journal of Veterinary Diagnostic Investigation, 2009
Over the past few decades, there have been increasing numbers of reports of diseases in marine tu... more Over the past few decades, there have been increasing numbers of reports of diseases in marine turtles. Furthermore, in recent years, there have been documented instances of apparently new diseases emerging in these species of which the etiology and/or pathogenesis remain unknown. These instances i) raise concern for the survival of marine turtles, and ii) question the health and stability of the benthic marine environments in which turtles live. Knowledge of common disease processes and pathologic changes in lesions, along with a standardized approach to postmortem and sample collection are required to document and understand the host-agent-environment interactions in marine turtle health. This review combines, for the first time, a standardized approach to the postmortem of marine turtles for veterinary clinicians, with a concurrent descriptive review of the gross and microscopic pathologic changes in lesions commonly seen.
Journal of Veterinary Diagnostic Investigation, 2009
Over the past few decades, there have been increasing numbers of reports of diseases in marine tu... more Over the past few decades, there have been increasing numbers of reports of diseases in marine turtles. Furthermore, in recent years, there have been documented instances of apparently new diseases emerging in these species of which the etiology and/or pathogenesis remain unknown. These instances i) raise concern for the survival of marine turtles, and ii) question the health and stability of the benthic marine environments in which turtles live. Knowledge of common disease processes and pathologic changes in lesions, along with a standardized approach to postmortem and sample collection are required to document and understand the host-agent-environment interactions in marine turtle health. This review combines, for the first time, a standardized approach to the postmortem of marine turtles for veterinary clinicians, with a concurrent descriptive review of the gross and microscopic pathologic changes in lesions commonly seen.
Cold stress syndrome (CSS) is the term used to describe the range of clinical signs and chronic d... more 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 coldrelated adverse events have been described in the closely related dugong Dugong dugon thus far, it has been established that they make movements in response to water temperatures lower than about 17 to 18°C. In this study, archive reports for dugong carcasses submitted to The University of Queensland School of Veterinary Science for post mortem examination during 2010 to 2012 were examined. These animals had been recovered from Moreton Bay, southeast Queensland, Australia, and 10 out of 14 fulfilled the criteria for 'potential cold stress cases.' Epidermal hyperplasia and secondary bacterial infection, serous atrophy of pericardial adipose tissue, and multisystem abscessation were features commonly noted in these cases. Water temperature data were correlated with the time of year that carcasses were submitted for examination. Higher numbers of carcasses diagnosed with potential CSS were noted during sustained periods in which water temperature was below 20°C. Given the pattern of increased submission of non-specifically, chronically unwell animals in the colder months and evidence that environmental conditions known to precipitate CSS occur in southeast Queensland, it is probable that, like manatees, dugongs in this area are affected by CSS. Further investigation to confirm and to better characterize the syndrome is recommended to refine management practices and improve treatment of affected animals.
Descriptions of the developmental stages of embryonic marine turtles are presented in the form of... more Descriptions of the developmental stages of embryonic marine turtles are presented in the form of a dichotomous key supported by drawings to facilitate identifying stages of development in the field. The key emphasizes the sequential appearance or loss of external morphological structures that can be seen either with the unaided eye or with a 310 hand lens and a handheld light. Stages are placed in the context of normal beach temperatures to facilitate estimation of laying date, emergence date, and events that cause embryonic mortality. Measurements of embryos are presented to assist determining stage.
• The broad aim of this project is to identify Management Units (MU) as the focal point for regio... more • The broad aim of this project is to identify Management Units (MU) as the focal point for regional management, with particular emphasis on Southeast Asia, but drawing also on broader studies through the Indo-Pacific. In this report we focus on results from analysis of green turtles in Southeast Asian and Western Pacific region, including samples from breeding and feeding populations and also major regional harvests. • We screened 670 nesting turtles from 27 breeding aggregations throughout Southeast Asia and the Western Pacific and 339 turtles from 3 feeding populations and 2 harvests in northern Australia, Papua New Guinea and Indonesia. These samples were assayed for variation in mitochondrial DNA (mtDNA) using gradient gel and sequencing methods. • We have identified 25 mtDNA variants shared among several rookeries with each rookery typically being characterised by a subset of 3-4 mtDNA variants. • A characteristic feature of green turtles in this region is strong divergence in frequencies of variants among breeding aggregations despite the widespread distribution of, and close relationships among many variants. • Based on evidence for significant genetic divergence we recognise the following 17 genetically discrete breeding units (Management Units) in the South East Asian and Western Pacific region:
Globally, tropical and subtropical regions have experienced an increased frequency and intensity ... more 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 variables and marine turtle stranding. The environmental variables examined in this study, in descending order of importance, were freshwater discharge, monthly mean maximum and minimum air temperatures, monthly average daily diurnal air temperature difference and rainfall for the latitudinal hotspots (-27˚,-25˚,-23˚,-19˚) along the Queensland coast as well as for major embayments within these blocks. This study found that marine turtle strandings can be linked to these environmental variables at different lag times (3-12 months), and that cumulative (months added together for maximum lag) and non-cumulative (single month only) effects cause different responses. Different latitudes also showed different responses of marine turtle strandings, both in response direction and timing.Cumulative effects of freshwater discharge in all latitudes resulted in increased strandings 10-12 months later. For latitudes-27˚,-25˚and-23˚non-cumulative effects for discharge resulted in increased strandings 7-12 months later. Latitude-19˚had different results for the noncumulative bay with strandings reported earlier (3-6 months). Monthly mean maximum and minimum air temperatures, monthly average daily diurnal air temperature difference and rainfall had varying results for each examined latitude. This study will allow first responders and resource managers to be better equipped to deal with increased marine turtle stranding rates following extreme weather events.
The ability of individuals to actively control their movements, especially during the early life ... more The ability of individuals to actively control their movements, especially during the early life stages, can significantly influence the distribution of their population. Most marine turtle species develop oceanic foraging habitats during different life stages. However, flatback turtles (Natator depressus) are endemic to Australia and are the only marine turtle species with an exclusive neritic development. To explain the lack of oceanic dispersal of this species, we predicted the dispersal of post-hatchlings in the Great Barrier Reef (GBR), Australia, using oceanographic advection-dispersal models. We included directional swimming in our models and calibrated them against the observed distribution of post-hatchling and adult turtles. We simulated the dispersal of green and loggerhead turtles since they also breed in the same region. Our study suggests that the neritic distribution of flatback post-hatchlings is favoured by the inshore distribution of nesting beaches, the local wate...
The problem of how to protect sea turtle nests from terrestrial predators is of worldwide concern... more The problem of how to protect sea turtle nests from terrestrial predators is of worldwide concern. On Queensland's southern Sunshine Coast, depredation of turtle nests by the introduced European red fox (Vulpes vulpes) has been recorded as the primary terrestrial cause of egg and hatchling mortality. We investigated the impact of foxes on the nests of the loggerhead turtle (Caretta caretta) and occasional green turtle (Chelonia mydas) over ten nesting seasons. Meshing of nests with fox exclusion devices (FEDs) was undertaken in all years accompanied by lethal fox control in the first five-year period, but not in the second five-year period. Lethal fox control was undertaken in the study area from 2005 to February 2010, but foxes still breached 27% (range19-52%) of turtle nests. In the second five-year period, despite the absence of lethal fox control, the average percentage of nests breached was less than 3% (range 0-4%). Comparison of clutch depredation rates in the two five-year periods demonstrated that continuous nest meshing may be more effective than lethal fox control in mitigating the impact of foxes on turtle nests. In the absence of unlimited resources available for the eradication of exotic predators, the use of FEDs and the support and resourcing of a dedicated volunteer base can be considered an effective turtle conservation tool on some beaches.
Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual ... more Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual animals, serves to educate the public, and contributes to conservation. We examined the outcome from rehabilitation, time in rehabilitation, and subsequent recapture and restranding rates of stranded marine turtles between 1996 and 2013 to determine if the benefits associated with this practice are cost-effective as a conservation tool. Of 13,854 marine turtles reported as stranded during this 18-year period, 5,022 of these turtles were stranded alive with the remainder verified as dead or of unknown condition. A total of 2,970 (59%) of these live strandings were transported to a rehabilitation facility. Overall, 1,173/2,970 (39%) turtles were released over 18 years, 101 of which were recaptured: 77 reported as restrandings (20 dead, 13 alive subsequently died, 11 alive subsequently euthanized, 33 alive) and 24 recaptured during normal marine turtle population monitoring or fishing activ...
NOTE Papers published in this volume and in all previous volumes of the Memoirs of the Queensland... more NOTE Papers published in this volume and in all previous volumes of the Memoirs of the Queensland Museummay be reproduced for scientific research, individual study or other educational purposes. Properly acknowledged quotations may be made but queries regarding the ...
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