Academic literature on the topic 'Krefft's River Turtle'

Fish, amphibians, and reptiles exhibit temperature-dependent ranaviral disease. We performed an experimental infection at four different environmental temperatures (16, 22, 28, and 34 °C) to investigate the effect of temperature on ranaviral infection in Krefft’s turtle ( Emydura macquarii krefftii). Infection rates and viral loads were determined by quantitative polymerase chain reaction to detect ranaviral DNA in liver samples at 21 d postexposure. The rate of infection differed across the temperature treatment groups. Infection rates were 44%, 90%, 60%, and 10% for the 16, 22, 28, and 34 °C temperature groups, respectively. Highest viral load was observed in the 28 °C temperature group, and there was a statistically significant difference in viral load between the 16 and 28 °C temperature groups ( p = 0.027). Based on the results of this study, the temperature of maximal infection rate for ranaviral infection in Krefft’s river turtles is estimated to be 23.2 °C (SD = 4.5). The findings of this study can inform management decisions in terms of disease control and treatment and form a platform for modelling disease outbreaks.

There is increasing recognition that microbiomes are important for host health and ecology, and understanding host microbiomes is important for planning appropriate conservation strategies. However, microbiome data are lacking for many taxa, including turtles. To further our understanding of the interactions between aquatic microbiomes and their hosts, we used next generation sequencing technology to examine the microbiomes of the Krefft’s river turtle (Emydura macquarii krefftii). We examined the microbiomes of the buccal (oral) cavity, skin on the head, parts of the shell with macroalgae and parts of the shell without macroalgae. Bacteria in the phyla Proteobacteria and Bacteroidetes were the most common in most samples (particularly buccal samples), but Cyanobacteria , Deinococcus-thermus and Chloroflexi were also common (particularly in external microbiomes). We found significant differences in community composition among each body area, as well as significant differences among individuals. The buccal cavity had lower bacterial richness and evenness than any of the external microbiomes, and it had many amplicon sequence variants (ASVs) with a low relative abundance compared to other body areas. Nevertheless, the buccal cavity also had the most unique ASVs. Parts of the shell with and without algae also had different microbiomes, with particularly obvious differences in the relative abundances of the families Methylomonaceae, Saprospiraceae and Nostocaceae . This study provides novel, baseline information about the external microbiomes of turtles and is a first step in understanding their ecological roles.

We determined the diet of Emydura krefftii, an abundant and widespread omnivorous freshwater turtle in north-eastern Australia, in an artificial urban impoundment. A potentially significant dietary influence is feeding of bread to the turtles by members of the public. This has led to the formation of a dense aggregation of the species at one end of the impoundment. The most substantial component of the diet by volume was the introduced weed Cabomba. Bread and figs were also important but only in specific locations. Bread was offered to turtles at the feeding aggregation in amounts close to the maximum eaten by captive turtles, and thus probably negatively influences nutrient status. Animal matter (insects, vertebrate carrion) was only a small proportion of the diet. We quantified intake, digestibility and transit time in the laboratory for four commonly occurring dietary items. Fish and bread were the most highly digestible food items and passed quickly through the gut. Despite its contribution to the diet in the wild, captive turtles ate little Cabomba, and it passed slowly through the gut and was poorly digested. Future research on interactive effects between diet items on digestive performance is recommended to understand the performance of turtles on apparently poor-quality diets.

An ecological study was undertaken on four populations of Krefft�s River Turtle Emydura krefftii inhabiting the Townsville Area of Tropical North Queensland. Two sites were located in the Ross River, which runs through the urban areas of Townsville, and two sites were in rural areas at Alligator Creek and Stuart Creek (known as the Townsville Creeks). Earlier studies of the populations in Ross River had determined that the turtles existed at an exceptionally high density, that is, they were superabundant, and so the Townsville Creek sites were chosen as low abundance sites for comparison. The first aim of this study was to determine if there had been any demographic consequences caused by the abundance of turtle populations of the Ross River. Secondly, the project aimed to determine if the impoundments in the Ross River had affected the freshwater turtle fauna. Specifically this study aimed to determine if there were any difference between the growth, size at maturity, sexual dimorphism, size distribution, and diet of Emydura krefftii inhabiting two very different populations. A mark-recapture program estimated the turtle population sizes at between 490 and 5350 turtles per hectare. Most populations exhibited a predominant female sex-bias over the sampling period. Growth rates were rapid in juveniles but slowed once sexual maturity was attained; in males, growth basically stopped at maturity, but in females, growth continued post-maturity, although at a slower rate. Sexual maturity was at 6-7 years of age for males, which corresponded to a carapace length of 150-160 mm, and 8-10 years of age for females, which corresponded to a carapace length of 185-240 mm. The turtles were omnivorous, although in the Ross River they ate more submerged vegetation (by percent amount and occurrence) than those of the Townsville Creeks. Turtles in Townsville Creeks ingested more windfall fruit and terrestrial insects.