Black noddies (Anous minutus) and wedge-tailed shearwaters (Puffinus pacificus) as potential hosts for fungi invading sea turtle nests at Heron Island, Queensland

Black noddies (Anous minutus) and wedge-tailed shearwaters (Puffinis pacificus) on Heron Island (Capricorn Group, Queensland) were surveyed to determine if they harboured fungi that had been implicated in sea turtle egg mortality in situ. Isolated from the cloacal exterior of these seabirds were Penicillium citrinum, Fusarium semitectum, F. trichothecioides, Aspergillus unguis, Aspergillus candidus, Acremonium sp., Alternaria sp. and Drechslera sp. These isolates are common soil or plant fungi and their most likely origin is therefore the nest or burrow material. None of these species have been isolated from sea turtle eggs that failed to hatch

Occurrence of cloacal prolapse in wild hylids in the Wet Tropics, Australia

The idiopathic syndrome of cloacal prolapse was observed in the frog Litoria rheocola at 2 sites in the Wet Tropics of Australia; 1 of 365 individuals (0.3%) at Tully Gorge National Park and 5 of 92 individuals (5.4%) at Murray Upper National Park. The condition appeared to have resolved spontaneously with no clinical complications in 2 individuals at successive captures 14 and 155 d later. It was not observed in the sympatric frogs L. genimaculata (n = 206), L. nannotis (n = 357) or Nyctimystes dayi (n = 304) at either location. The underlying cause was not conclusively determined

Mating system, multiple paternity and effective population size in the endemic flatback turtle (Natator depressus) in Australia

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

Storage of samples at high temperatures reduces the amount of amphibian chytrid fungus Batrachochytrium dendrobatidis DNA detectable by PCR assay

Chytridiomycosis, caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease responsible for amphibian declines on several continents. In laboratory conditions, optimal temperatures for Bd growth and survivorship are between 17 and 25°C. We investigated the effect of different storage temperatures, both in field and laboratory conditions, on detection of Bd from swabs stored for 7 d. We sampled 52 wild Litoria wilcoxii males for Bd by simultaneously running 2 cotton swabs along the skin of the frog. One group of swabs was stored in a freezer within 2 h of sampling and the other was kept in a car in an exposed environment for 7 d before being stored in the freezer. In the laboratory experiment, swabs were inoculated with zoospores of Bd and underwent one of 4 treatments: immediate DNA extraction, or storage at 27, 38 or 45°C for 7 d prior to DNA extraction. Swabs from all treatments were analyzed by quantitative (real-time) PCR test. Though prevalence of Bd did not differ significantly between swabs that were frozen and those that remained in a car for 7 d (19.2 vs. 17.3%, respectively), the number of Bd zoospores detected on car swabs taken from infected frogs was, on average, 67% less than that detected on the corresponding frozen swab. In the laboratory experiment, the number of zoospore equivalents varied significantly with treatment (F3,35 = 4.769, p = 0.007), indicating that there was reduced recovery of Bd DNA from swabs stored at higher temperatures compared with those stored at lower temperatures or processed immediately. We conclude that failure to store swabs in cool conditions can result in a significant reduction in the amount of Bd DNA detected using the PCR assay. Our results have important implications for researchers conducting field sampling of amphibians for Bd

Minimising exposure of amphibians to pathogens during field studies

Many of the recent global amphibian mass mortalities, declines and extinctions have been attributed to the emerging infectious disease chytridiomycosis. There have been mass mortalities due to ranaviral disease but no major declines or extinctions. Controlling the transmission and spread of disease is of utmost importance, especially where there is the potential for human involvement. We have reviewed current hygiene guidelines for working with wild frogs, identified potential flaws and recommended those most suitable and effective for the field environment. Our within-site hygiene measures aim to reduce the risk of transmission among individuals. These measures encompass the capture, handling and holding of amphibians, skin disinfection before and after invasive procedures, marking frogs, sealing open wounds and treatment of accessory equipment. Our between-site hygiene measures aim to mitigate the risk of pathogen spread among populations. We have designed a risk calculator to help simplify and standardise the decision-making process for determining the level of risk and appropriate risk mitigation strategies to reduce the risk of increasing pathogen spread above background levels. Calculation of an overall risk score for pathogen spread takes into account the prior activity of field workers, the proposed activity, remoteness of the site, presence of known pathogens and the consequences of increased pathogen spread for amphibians in a given area

Reflections on sea turtle conservation

[Extract] Why do sea turtles garner such intense interest? The answer is visceral: they are widely loved! A cryptic life cycle spent mostly out of view lends a sense of mystery that makes them special. Yet, these large animals are highly accessible at an extremely vulnerable time, when females emerge on sandy beaches at night to lay eggs, before disappearing again into the oceans. Being nocturnal, they provide us the adventure of going out in the dark on secluded beaches to find them. Plus, the hatchlings are cute, and releasing them into the sea must be one of the most engaging activities that people can do with a protected species. To mark World Sea Turtle Day on 16 June, we—conservation scientists working across the oceans on this small yet well-studied group of seven species—reflect on their conservation. Sea turtles have lived in the oceans, largely unchanged, for millions of years. They play important roles in their ecosystems, possibly even as ecosystem engineers, and serve as prey for other protected species (Veríssimo et al., 2012). They have been a source of sustenance and useful products for people for millennia, and these needs persist (Hancock et al., 2017; Humber et al., 2017; Delisle et al., 2018; Sardeshpande & MacMillan, 2019). Consequently, sea turtles are culturally important and the subject of myths and lore. They have also become economically important to many coastal communities through tourism (Waylen et al., 2009), although this can affect turtles or their habitats, if not correctly managed (Katselidis et al., 2013)

Diagnostic assays and sampling protocols for the detection of Batrachochytrium dendrobatidis

Batrachochytrium dendrobatidis is a fungus belonging to the Phylum Chytridiomycota, Class Chytridiomycetes, Order Chytridiales, and is the highly infectious aetiological agent responsible for a potentially fatal disease, chytridiomycosis, which is currently decimating many of the world’s amphibian populations. The fungus infects 2 amphibian orders (Anura and Caudata), 14 families and at least 200 species and is responsible for at least 1 species extinction. Whilst the origin of the agent and routes of transmission are being debated, it has been recognised that successful management of the disease will require effective sampling regimes and detection assays. We have developed a range of unique sampling protocols together with diagnostic assays for the detection of B. dendrobatidis in both living and deceased tadpoles and adults. Here, we formally present our data and discuss them in respect to assay sensitivity, specificity, repeatability and reproducibility. We suggest that compliance with the recommended protocols will avoid the generation of spurious results, thereby providing the international scientific and regulatory community with a set of validated procedures which will assist in the successful management of chytridiomycosis i

Methodology for investigating the distribution and determinants of Chytridiomycosis

Chytridiomycosis is an important emerging pandemic infectious disease of amphibians. Investigating this disease has been challenging due to a lack of knowledge and expertise in studying disease in amphibians in general, and because of the novel nature of the pathogen, Batrachochytrium dendrobatidis (Bd), which is the first chytrid fungus known to cause disease in vertebrates. Bd is difficult to isolate and has a diverse and wide host range, and frog population sizes are largely unknown and the ability to find frogs varies with climatic conditions. We have adapted veterinary and zoological methods and expertise to examine the distribution and determinants of chytridiomycosis. Our studies of the determinants of chytridiomycosis have involved research at multiple levels. We have examined correlations of disease prevalence with environmental, climatic and host variables. Within populations, we use mark-recapture methods to estimate incidence and mortality rates and relate these to possible determinants. At the level of the individual host, we use radio telemetry to examine the effects of host behaviour and microenvironment on infection and transmission mechanisms. In the laboratory, experimental infections are used to test and demonstrate relationships between determinants and chytridiomycosis. It is expected that understanding the epidemiology of this disease will lead to better management of chytridiomycosis and improved conservation for frogs