The importance of sample size in marine megafauna tagging studies.

Telemetry is a key, widely used tool to understand marine megafauna distribution, habitat use, behavior, and physiology; however, a critical question remains: "How many animals should be tracked to acquire meaningful data sets?" This question has wide-ranging implications including considerations of statistical power, animal ethics, logistics, and cost. While power analyses can inform sample sizes needed for statistical significance, they require some initial data inputs that are often unavailable. To inform the planning of telemetry and biologging studies of marine megafauna where few or no data are available or where resources are limited, we reviewed the types of information that have been obtained in previously published studies using different sample sizes. We considered sample sizes from one to >100 individuals and synthesized empirical findings, detailing the information that can be gathered with increasing sample sizes. We complement this review with simulations, using real data, to show the impact of sample size when trying to address various research questions in movement ecology of marine megafauna. We also highlight the value of collaborative, synthetic studies to enhance sample sizes and broaden the range, scale, and scope of questions that can be answered.

Dietary partitioning by five sympatric species of stingray (Dasyatidae) on coral reefs.

Dietary characteristics and the degree of dietary partitioning by five species of sympatric stingray were assessed using stomach content and sediment analyses within a coral reef lagoon at Ningaloo Reef, Western Australia (the cowtail Pastinachus atrus, blue-spotted fantail Taeniura lymma, blue-spotted mask Neotrygon kuhlii, porcupine Urogymnus asperrimus rays and the reticulate whipray Himantura uarnak). A total of 2804 items were recovered from the stomachs of 170 rays and 3215 individual taxa from the environment, which were used in selectivity analyses. Twenty-four prey taxa were identified from stomach contents and pooled into 10 taxonomic categories for analysis, of which annelids, prawns, brachyurans and bivalves were the most abundant, together accounting for 96% of the diet. Himantura uarnak had the greatest interspecific dissimilarity in diet, consuming a larger proportion of crustaceans, notably penaeids (41% of total diet) than the other four species of rays, all of which had diets dominated by annelids (71-82% of total diet). Crustacean specialization by H. uarnak may exist to maximize resources and reduce competition among sympatric species. The remaining species may partition resources on the basis of space, rather than diet.

Oral manifestations of syphilis: an epidemiological study in southern Brazil.

BACKGROUND: Syphilis is an infectious, sexually transmitted disease with varied oral manifestations, that can mimic other lesions. This study aimed to conduct an epidemiological survey of cases of syphilis, diagnosed from oral manifestations, establishing the sociodemographic profile of patients and clinical characteristics of oral lesions. METHODS: The medical records of patients with oral lesions of syphilis acquired were reviewed, and 109 cases were selected. RESULTS: The mean age of the patients was 34.4 years and, of these, 51% were male. In 105 cases, the disease was diagnosed in the secondary stage; in three cases, in the primary stage; and, in one case, in the tertiary stage. The cases of primary syphilis presented as single and ulcerated nodules, and the case of tertiary syphilis, as a necrotic lesion in the palate. In 86% of cases of secondary syphilis, there were multicentric lesions, presenting as grayish-white plaques (85%), associated or not with erosive and/or ulcerated lesions (33%), mostly affecting the labial mucosa and tongue. In 91.7% of cases painful symptoms were reported. CONCLUSION: Considering the increase in syphilis, it is extremely important that dentists recognize its oral manifestations, because early diagnosis and treatment can minimize the risks of complications and transmission.