RESUMEN
Biological investigations on free ranging marine species are regarded as challenging throughout the scientific community. This is particularly true for 'logistically difficult species' where their cryptic natures, low abundance, patchy distributions and difficult and/or dangerous sampling environments, make traditional surveys near impossible. What results is a lack of ecological knowledge on such marine species. However, advances in UAV technology holds potential for overcoming these logistical difficulties and filling this knowledge gap. Our research focused on one such logistically difficult species, the Australian box Jellyfish (Chironex fleckeri), and we investigated the capacity of consumer grade UAV technology to detect this, highly venomous, target species in the inshore waters of Northern Queensland Australia. At two sites in the Weipa area, we utilized video analysis, visual count comparisons with a netted animal tally, and evaluated the role of associated environmental conditions, such as wind speed, water visibility and cloud cover on jellyfish detection rates. In total fifteen, 70 meter transects were completed between two sites, with 107 individuals captured. Drone success varied between the two sites with a significant difference between field and post-field (laboratory) counts. Animal size and cloud cover also had significant effects on detection rates with an increase in cloud cover and animal size enhancing detection probability. This study provides evidence to suggest drone surveys overcome obstacles that traditional surveys can't, with respect to species deemed logistically difficult and open scope for further ecological investigations on such species.
Asunto(s)
Cubomedusas , Monitoreo del Ambiente/instrumentación , Encuestas y Cuestionarios , Animales , Tamaño Corporal , Cubomedusas/anatomía & histología , Dinámica PoblacionalRESUMEN
This research explores the thermal and osmotic tolerance of the polyp stage of the Irukandji jellyfish Carukia barnesi, which provides new insights into potential polyp habitat suitability. The research also targets temperature, salinity, feeding frequency, and combinations thereof, as cues for synchronous medusae production. Primary findings revealed 100% survivorship in osmotic treatments between 19 and 46, with the highest proliferation at 26. As salinity levels of 26 do not occur within the waters of the Great Barrier Reef or Coral Sea, we conclude that the polyp stage of C. barnesi is probably found in estuarine environments, where these lower salinity conditions commonly occur, in comparison to the medusa stage, which is oceanic. Population stability was achieved at temperatures between 18 and 31°C, with an optimum temperature of 22.9°C. We surmise that C. barnesi polyps may be restricted to warmer estuarine areas where water temperatures do not drop below 18°C. Asexual reproduction was also positively correlated with feeding frequency. Temperature, salinity, feeding frequency, and combinations thereof did not induce medusae production, suggesting that this species may use a different cue, possibly photoperiod, to initiate medusae production.
Asunto(s)
Adaptación Fisiológica , Cubomedusas/fisiología , Ósmosis , Temperatura , Animales , Ambiente , Conducta Alimentaria , Funciones de Verosimilitud , Reproducción Asexuada/fisiologíaRESUMEN
Adult medusae of Carukia barnesi were collected near Double Island, North Queensland Australia. From 73 specimens, 8 males and 15 females spawned under laboratory conditions. These gametes were artificially mixed which resulted in fertilized eggs. Post fertilization, most eggs developed to an encapsulated planula stage and then paused for between six days and six months prior to hatching as ciliated planulae. The paused stage planulae were negatively buoyant and adhered to substrate. The first planula was produced six days post fertilization, lacked larval ocelli, remained stationary, or moved very slowly for two days prior to metamorphosis into primary polyps. Mature polyps reproduced through asexual reproduction via lateral budding producing ciliated swimming polyps, which in turn settled and developed into secondary polyps. Medusae production for this species was in the form of monodisc strobilation, which left behind polyps able to continue asexual reproduction.
Asunto(s)
Cubomedusas/fisiología , Animales , Femenino , Estadios del Ciclo de Vida , Masculino , Reproducción AsexuadaRESUMEN
PURPOSE: To develop criteria to identify thresholds for minimally acceptable physician performance in interpreting screening mammography studies and to profile the impact that implementing these criteria may have on the practice of radiology in the United States. MATERIALS AND METHODS: In an institutional review board-approved, HIPAA-compliant study, an Angoff approach was used in two phases to set criteria for identifying minimally acceptable interpretive performance at screening mammography as measured by sensitivity, specificity, recall rate, positive predictive value (PPV) of recall (PPV(1)) and of biopsy recommendation (PPV(2)), and cancer detection rate. Performance measures were considered separately. In phase I, a group of 10 expert radiologists considered a hypothetical pool of 100 interpreting physicians and conveyed their cut points of minimally acceptable performance. The experts were informed that a physician's performance falling outside the cut points would result in a recommendation to consider additional training. During each round of scoring, all expert radiologists' cut points were summarized into a mean, median, mode, and range; these were presented back to the group. In phase II, normative data on performance were shown to illustrate the potential impact cut points would have on radiology practice. Rescoring was done until consensus among experts was achieved. Simulation methods were used to estimate the potential impact of performance that improved to acceptable levels if effective additional training was provided. RESULTS: Final cut points to identify low performance were as follows: sensitivity less than 75%, specificity less than 88% or greater than 95%, recall rate less than 5% or greater than 12%, PPV(1) less than 3% or greater than 8%, PPV(2) less than 20% or greater than 40%, and cancer detection rate less than 2.5 per 1000 interpretations. The selected cut points for performance measures would likely result in 18%-28% of interpreting physicians being considered for additional training on the basis of sensitivity and cancer detection rate, while the cut points for specificity, recall, and PPV(1) and PPV(2) would likely affect 34%-49% of practicing interpreters. If underperforming physicians moved into the acceptable range, detection of an additional 14 cancers per 100000 women screened and a reduction in the number of false-positive examinations by 880 per 100000 women screened would be expected. CONCLUSION: This study identified minimally acceptable performance levels for interpreters of screening mammography studies. Interpreting physicians whose performance falls outside the identified cut points should be reviewed in the context of their specific practice settings and be considered for additional training.