Streptococcus iniae causes high mortality in cultured and wild fish stocks globally. Since the first report in captive Amazon river dolphins Inia geoffrensis in 1976, it has emerged in finfish across all continents except Antarctica. In March 2016, an estimated 17000 fish were observed dead and dying along a remote 70 km stretch of the Kimberley coastline north of Broome, Western Australia. Affected species included finfish (lionfish Pterois volitans , angelfish Pomacanthus sp., stripey snapper Lutjanus carponotatus , sand bass Psammoperca waigiensis , yellowtail grunter Amniataba caudavittata , damselfish Pomacentridae sp.), flatback sea turtles Natator depressus , and olive ( Aipysurus laevis ) and black-ringed ( Hydrelaps darwiniensis ) sea snakes. Moribund fish collected during the event exhibited exophthalmia and abnormal behaviour, such as spiralling on the surface or within the water column. Subsequent histopathological examination of 2 fish species revealed bacterial septicaemia with chains of Gram-positive cocci seen in multiple organs and within brain tissue. S. iniae was isolated and identified by bacterial culture, species-specific PCR, Matrix-Assisted Laser Desorption Ionisation Time-Of-Flight (MALDI-TOF) and biochemical testing. This is the first report of S. iniae associated with a major multi-species wild marine fish kill in Australia. Extreme weather events in the region including a marked decrease in water temperatures, followed by an extended period of above-average coastal water temperatures, were implicated as stressors potentially contributing to this outbreak.
It is well known that light pollution disrupts the early dispersal of marine turtles. But now, light emitting diodes (LEDs) are replacing traditional lights, however, we know little about how they influence hatchling dispersal. Here, we used acoustic telemetry to assess the early in-water dispersal and predation rates of hatchlings in response to different intensities of LEDs ranging from 10 to 120 W. We found no effect of LEDs on hatchling bearing when lights were in the direction they dispersed under ambient conditions. When LEDs were not in their usual direction of travel, variability in mean bearing increased, and a change in bearing occurred with the highest light intensity. We found weak evidence that predation was also higher at this light intensity compared to ambient, and also in two of the lower light intensities (10 and 30 W), but only on one experimental night. We were unable to find a relationship between hatchling speed and time spent in the tracking area with light intensity. However, reduced sample sizes (due to predation) might have affected our ability to detect effects. Although more effort is required to increase the confidence in our findings, LEDs disrupted hatchling dispersal and are therefore likely to negatively affect their survival.
Australia’s endemic flatback turtle Natator depressus is the focus of a long-term conservation program aimed at securing the persistence of healthy populations in the northwest of Australia into the future. Primary threats to flatback turtles include (1) sea level rise, (2) predation from introduced species, (3) temperature increases, (4) onshore and nearshore light, (5) marine debris, and (6) modification to beaches. Population declines resulting from these threats have been reported or are anticipated, and a range of intervention options are possible that may limit their negative impact. Following methods previously developed and applied to iconic marine species and habitats, we generated a range of intervention options, and asked experts to prioritise those actions using an intervention prioritisation tool (IPT) and the public to prioritise based on social acceptability assessment (SAS). The IPT allows different conservation interventions to be assessed based on their economic cost, implementation feasibility, social acceptability, and perceived effectiveness in maintaining or increasing future turtle populations while simultaneously accounting for expert confidence in their assessment. Results generated by the IPT and SAS can be explored further to resolve uncertainty, a process that can help managers and experts alike in their decision-making process associated with flatback conservation. While this paper is focused on interventions relating to flatback turtles, we propose that our IPT can be applied in different settings to enable consideration of interventions for a range of threatened species and habitats to guide research and conservation investment decisions by managers.
Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score.This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally.Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification.The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy.
A severe lack of distribution data for aquatic reptiles in northern Australia leaves many taxa vulnerable to extirpation and extinction. Environmental DNA (eDNA) technologies offer sensitive and non-invasive genetic alternatives to trapping and visual surveys and are increasingly employed for the detection of aquatic and semi-aquatic reptiles. However, these eDNA approaches have largely applied species-specific primers that do not provide a cost-effective avenue for the simultaneous detection of multiple reptilian taxa. Here, we present a mitochondrial 16S rRNA metabarcoding assay for the broad detection of aquatic and semi-aquatic reptile species. This assay is tested on water samples collected at multiple sampling sites at two tropical locations, including 12 marine and estuarine sites in Roebuck Bay, Western Australia, and four estuarine sites in Cooktown, Queensland, Australia. In total, nine reptile taxa were detected from 10 of the 16 sampled sites, including marine and freshwater turtles, aquatic, semi-aquatic and terrestrial snakes, and terrestrial skinks. However, inconsistencies in the detection of previously observed aquatic reptiles at our sampled sites, such as saltwater crocodile and sea snakes, indicated that further research is required to assess the reliability, strengths and limitations of eDNA methods for aquatic reptile detection before it can be integrated as a broad-scale bioassessment tool.
Context Quantifying marine turtle-nest depredation by daily observer monitoring requires substantial labour. Aims To quantify nest depredation of the Vulnerable flatback turtle (Natator depressus) at one of its largest rookeries and to compare effectiveness of different monitoring methods. Methods We used daily observer monitoring and passive infrared-camera traps separately or in combination to record nest depredation, and identified impacts on remaining eggs and hatchlings in depredated nests. Key results More than a quarter (28%) of the 69 monitored nests were confirmed as depredated, although this figure is an underestimate of total losses because camera traps detected twice as many depredation events (39%) as did direct observation (17%) (P = 0.012). Cameras also provided important behavioural data and identified predators. Although reptile and bird predators were also recorded, the introduced red fox (Vulpes vulpes) was the primary predator identified, digging into 26% of the monitored nests. More than half of the depredation events by foxes (58% or 11/19 nests) occurred late term, between turtles hatching and emerging from the nest, which therefore means that losses calculated through counts of eggshell left in the nest are underestimates because predation of hatchlings is not included by the eggshell count method. Furthermore, almost half (42%) of all depredated nests were depredated more than once, with some nests opened up to five times, potentially exacerbating clutch losses due to environmental exposure. Conclusions Egg losses for confirmed depredated nests (27 ± 37%, range 0–100%) were three times the background levels (i.e. 9.3% of eggs that failed to hatch as a result of embryo death during development). Implications The results of this study strongly warrant the implementation of ongoing fox predator monitoring and mitigation strategies to protect nests at this nationally, and internationally, conservation-significant population of flatback turtles.
Four spedes of marine mammals were observed from a small boat during sea-turtle research activities in Fog Bay, west of Darwin.The Indo-Pacific hump-backed dolphin was the most frequently sighted, followed by the dugong, Irrawaddy dolphin and bottlenose dolphin.Details of each sighting, including exact location, season, group size and number of calves are provided.
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