A roadmap to define and select aquatic biological traits at different scales of analysis.

Trait-based approaches are a powerful tool, as they not only improve understanding of ecological complexity and functioning but also allow comparison across different ecosystems and biogeographical regions. They may be used to unveil ecosystem processes and assess community structures, but their great potential becomes limited when dealing with scattered trait data and historically unstandardised trait nomenclature. The lack of standardisation allows authors to use the terminology of their preference, which inevitably leads to ambiguous misunderstandings and limits comparison between different studies. There have been some attempts to organise the trait vocabulary, but even these are mostly created from the perspective of a single ecosystem, which limits their applicability. In this work, we conducted a systematic literature review that identified and compiled 1127 traits across 37 datasets of fishes, invertebrates and zooplankton from freshwater, marine and transitional ecosystems. This dataset was then used to build on the Marine Species Traits Wiki and to propose a new, unified approach to a trait vocabulary based directly on readily available trait data. We propose a single standardised designation for all the different traits identified and provide a list of all the different synonyms commonly used for these traits. A roadmap to help the trait selection process is also provided, offering a guide through four main steps and important questions for choosing an adequate set of traits at the beginning of any study, which constitutes one of the main challenges in functional ecology research. Overall, this proposal will provide a solid baseline for tackling gaps in trait nomenclature and ensuring a clearer future for functional ecology studies.

Elemental and spectral chemometric analyses of Octopus vulgaris beaks as reliable markers of capture location.

The high demand and economic relevance of cephalopods make them prone to food fraud, including related to harvest location. Therefore, there is a growing need to develop tools to unequivocally confirm their capture location. Cephalopod beaks are nonedible, making this material ideal for traceability studies as it can also be removed without a loss of commodity economic value. Within this context, common octopus (Octopus vulgaris) specimens were captured in five fishing areas along the Portuguese coast. Untargeted multi-elemental total X-ray fluorescence analysis of the octopus beaks revealed a high abundance of Ca, Cl, K, Na, S, and P, concomitant with the keratin and calcium phosphate nature of the material. We tested a suite of discrimination models on both elemental and spectral data, where the elements contributing most to discriminate capture location were typically associated with diet (As), human-related pressures (Zn, Se, and Mn), or geological features (P, S, Mn, and Zn). Among the six different chemometrics approaches used to classify individuals to their capture location according to their beaks' element concentration, classification trees attained a classification accuracy of 76.7%, whilst reducing the number of explanatory variables for sample classification and highlighting variable importance for group discrimination. However, using X-ray spectral features of the octopus beaks further improved classification accuracy, with the highest classification of 87.3% found with partial least-squares discriminant analysis. Ultimately, element and spectral analyses of nonedible structures such as octopus beaks can provide an important, complementary, and easily accessible means to support seafood provenance and traceability, whilst integrating anthropogenic and/or geological gradients.

Elemental Fingerprinting of Wild and Farmed Fish Muscle to Authenticate and Validate Production Method.

In the context of expanding fish production and complex distribution chains, traceability, provenance and food safety tools are becoming increasingly important. Here, we compare the elemental fingerprints of gilthead seabream (Sparus aurata) muscle from wild and different aquaculture productions (semi-intensive earth ponds and intensive sea cages from two locations) to confirm their origin and evaluate the concentrations of elements with regulatory thresholds (Cu, Hg, Pb and Zn). Using a chemometric approach based on multi-elemental signatures, the sample origin was determined with an overall accuracy of 90%. Furthermore, in a model built to replicate a real-case scenario where it would be necessary to trace the production method of S. aurata without reliable information about its harvesting location, 27 of the 30 samples were correctly allocated to their original production method (sea-cage aquaculture), despite being from another location. The concentrations of the regulated elements ranged as follows: Cu (0.140-1.139 mg/Kg), Hg (0-0.506 mg/Kg), Pb (0-2.703 mg/Kg) and Zn (6.502-18.807 mg/Kg), with only Pb presenting concentrations consistently above the recommended limit for human consumption. The present findings contribute to establishing elemental fingerprinting as a reliable tool to trace fish production methods and underpin seafood authentication.

Harnessing the Full Power of Chemometric-Based Analysis of Total Reflection X-ray Fluorescence Spectral Data to Boost the Identification of Seafood Provenance and Fishing Areas.

Provenance and traceability are crucial aspects of seafood safety, supporting managers and regulators, and allowing consumers to have clear information about the origin of the seafood products they consume. In the present study, we developed an innovative spectral approach based on total reflection X-ray fluorescence (TXRF) spectroscopy to identify the provenance of seafood and present a case study for five economically relevant marine species harvested in different areas of the Atlantic Portuguese coast: three bony fish-Merluccius merluccius, Scomber colias, and Sparus aurata; one elasmobranch-Raja clavata; one cephalopod-Octopus vulgaris. Applying a first-order Savitzky-Golay transformation to the TXRF spectra reduced the potential matrix physical effects on the light scattering of the X-ray beam while maintaining the spectral differences inherent to the chemical composition of the samples. Furthermore, a variable importance in projection partial least-squares discriminant analysis (VIP-PLS-DA), with k - 1 components (where k is the number of geographical origins of each seafood species), produced robust high-quality models of classification of samples according to their geographical origin, with several clusters well-evidenced in the dispersion plots of all species. Four of the five species displayed models with an overall classification above 80.0%, whereas the lowest classification accuracy for S. aurata was 74.2%. Notably, about 10% of the spectral features that significantly contribute to class differentiation are shared among all species. The results obtained suggest that TXRF spectra can be used for traceability purposes in seafood species (from bony and cartilaginous fishes to cephalopods) and that the presented chemometric approach has an added value for coupling with classic TXRF spectral peak deconvolution and elemental quantification, allowing characterization of the geographical origin of samples, providing a highly accurate and informative dataset in terms of food safety.

Assessing spatio-temporal changes in marine communities along the Portuguese continental shelf and upper slope based on 25 years of bottom trawl surveys.

The Portuguese continental coast is influenced by several oceanographic processes and is located near the confluence of three biogeographic realms (from the North Atlantic, South Atlantic and Mediterranean). Given these features, the topography of the Portuguese coast, possible variations in fishing effort and reported increasing sea surface temperature in the last decades, we hypothesized that changes in marine communities in space and time occurred since 1990. In this study, research survey data collected yearly along the Portuguese continental slope (20-500 m deep) from 1990 to 2016 were analysed with the objective of identifying spatio-temporal changes. Latitude and depth were found to play a major role in communities' spatial differentiation, probably associated to temperature, and three ecological areas were defined (north, southwest and south). In the studied period, Macroramphosus spp. abundance showed a marked decrease in all areas whereas Sparids increased in abundance in the south. Despite these major changes and fluctuations in species abundance over time no major trends in communities were observed. Fishing activity, environmental conditions (including climate change) and biotic factors are all drivers possibly responsible for those changes.

Extrinsic and intrinsic factors shape the ability of using otolith chemistry to characterize estuarine environmental histories.

Reconstructing habitat use and environmental histories of fish via otolith chemistry relies on linking otolith chemical composition to the surrounding environment, as well as disentangling the consequences of ontogenetic or physiological effects that may mask environmental signals. We used multiple linear and linear mixed models to analyse the importance of environmental (temperature, salinity, water chemistry) and individual based (fish size) factors on otolith chemical composition and incorporation (Li, Mg, Mn, Sr, and Ba) of juvenile Dicentrarchus labrax, over their time within an estuarine nursery area. Multi model inference highlighted the importance of ontogeny, as well as the influence of temperature and salinity on otolith chemistry and elemental incorporation, with results indicating that intrinsic effects may potentially outweigh environmental effects. Ultimately, understanding if otolith chemistry accurately reflects fine-scale environmental variation is key to reconstruct environmental histories of juvenile fishes in estuaries and will contribute to determining the impact changing estuarine conditions may have on growth and survival.

Reconciling differences in natural tags to infer demographic and genetic connectivity in marine fish populations.

Processes regulating population connectivity are complex, ranging from extrinsic environmental factors to intrinsic individual based features, and are a major force shaping the persistence of fish species and population responses to harvesting and environmental change. Here we developed an integrated assessment of demographic and genetic connectivity of European flounder Platichthys flesus in the northeast Atlantic (from the Norwegian to the Portuguese coast) and Baltic Sea. Specifically, we used a Bayesian infinite mixture model to infer the most likely number of natal sources of individuals based on otolith near core chemical composition. Simultaneously, we characterised genetic connectivity via microsatellite DNA markers, and evaluated how the combined use of natural tags informed individual movement and long-term population exchange rates. Individual markers provided different insights on movement, with otolith chemistry delineating Norwegian and Baltic Sea sources, whilst genetic markers showed a latitudinal pattern which distinguished southern peripheral populations along the Iberian coast. Overall, the integrated use of natural tags resulted in outcomes that were not readily anticipated by individual movement or gene flow markers alone. Our ecological and evolutionary approach provided a synergistic view on connectivity, which will be paramount to align biological and management units and safeguard species' biocomplexity.

Short-term variability of fish condition and growth in estuarine and shallow coastal areas.

Short-term variability in condition factor: relative condition factor Kn; biochemical condition: RNA:DNA and protein content; and instantaneous growth rates were determined in estuarine and coastal fish. Dicentrarchus labrax, Solea senegalensis and Pomatoschistus microps were sampled in the Tejo estuary, while Trachurus trachurus was sampled in an adjacent shallow coastal area. Variation of condition indices was more frequent at the week scale (sampling periods with fortnight intervals) than at the daily scale (consecutive days in each sampling period) in all species. Water temperature was correlated with biochemical indices, while salinity showed no effect, evidencing the influence of environmental short-term variation (temperature) on biochemical condition in natural populations. Yet, decreasing individual variability in fish condition was observed along the sampled weeks, resulting in a more homogeneous condition of populations, particularly for T. trachurus likely due to a more stable coastal environment. Biochemical indices proved to be sensitive to short-term environmental variability, despite species-specific responses.

Current limitations of global conservation to protect higher vulnerability and lower resilience fish species.

Estuaries are threatened by intense and continuously increasing human activities. Here we estimated the sensitivity of fish assemblages in a set of estuaries distributed worldwide (based on species vulnerability and resilience), and the exposure to cumulative stressors and coverage by protected areas in and around those estuaries (from marine, estuarine and freshwater ecosystems, due to their connectivity). Vulnerability and resilience of estuarine fish assemblages were not evenly distributed globally and were driven by environmental features. Exposure to pressures and extent of protection were also not evenly distributed worldwide. Assemblages with more vulnerable and less resilient species were associated with estuaries in higher latitudes (in particular Europe), and with higher connectivity with the marine ecosystem, moreover such estuaries were generally under high intensity of pressures but with no concomitant increase in protection. Current conservation schemes pay little attention to species traits, despite their role in maintaining ecosystem functioning and stability. Results emphasize that conservation is weakly related with the global distribution of sensitive fish species in sampled estuaries, and this shortcoming is aggravated by their association with highly pressured locations, which appeals for changes in the global conservation strategy (namely towards estuaries in temperate regions and highly connected with marine ecosystems).

Contrasting patterns of energy metabolism in northern vs southern peripheral European flounder populations exposed to temperature rising and hypoxia.

A two months common garden experiment was carried out to explore the potential differences of energy metabolism in northern core (France, 50°N and 47°N) vs southern peripheral (Portugal, 41°N) populations of European flounder Platichthys flesus, submitted to cold condition (CC: water temperature = 10 °C) and to warm and hypoxic condition (WHC: water temperature = 22 °C, and moderate hypoxia with O2 saturation = 40% during the last 6 days). Convergent growth rates (in length) were observed in the different populations and conditions, when the southern peripheral population of Portugal did not grow under cold conditions. A general reduction in liver lipid storage was observed in all populations subjected to WHC when compared to CC, whereas muscle lipid storage was unaffected. The thermal and hypoxia treatment induced changes in muscle phospholipids (PL) ratios: phosphatidylserine/PL, phosphatidylinositol/PL, between northern and southern populations. Fish from northern estuaries displayed marked anaerobiosis in WHC (increased liver LDH activity) vs marked aerobiosis under CC (higher muscle CS and CCO activities). Contrariwise, fish from the southern estuary displayed equilibrium between anaerobiosis and aerobiosis activities in WHC. Flounders from the southern population exhibited generally lower G6PDH activity (proxy for anabolism and for defense against oxidative damage), tissue-specific anaerobiosis response (muscle LDH activity) and lower CS and CCO muscle activities (aerobiosis markers) when compared to northern populations. Globally, these inter-population differences in bioenergetics suggest that southern peripheral vs northern core populations have developed differential capacity to cope with interacting stressors and that much of this variation is more likely due to local adaptation.

Características dos primeiros casos de microcefalia possivelmente relacionados ao vírus Zika notificados na Região Metropolitana de Recife, Pernambuco / Características de los primeros casos de microcefalia, posiblemente relacionadas con el virus Zika reportados en la Región Metropolitana de Recife / Characteristics of the first cases of microcephaly possibly related to Zika virus reported in the Metropolitan Region of Recife, Pernambuco State, Brazil

OBJETIVO: descrever os primeiros casos de microcefalia possivelmente relacionados ao vírus Zika em nascidos vivos notificados na Região Metropolitana do Recife, Pernambuco, Brasil. MÉTODOS: estudo descritivo de tipo série de casos (notificados de 1º de agosto a 31 de outubro de 2015), com dados obtidos dos registros médicos e de questionário aplicado às mães. RESULTADOS: foram confirmados 40 casos com microcefalia, distribuídos em oito municípios da Região Metropolitana do Recife, com maior concentração no Recife (n=12); a mediana do perímetro cefálico foi de 29 cm, do perímetro torácico, 31 cm, e do peso, 2.628 gramas; 21/25 casos apresentaram calcificação cerebral, ventriculomegalia ou lisencefalia; entre as 40 mães, 27 referiram exantema na gestação, 20 no primeiro trimestre e sete no segundo, além de prurido, cefaleia, mialgia e ausência de febre. CONCLUSÃO: a maioria dos casos apresentou características de infecção congênita; a maioria das mães apresentou quadro sugestivo de infecção pelo vírus Zika na gestação.

OBJETIVO: describir los primeros casos de microcefalia en nacidos vivos reportados al Departamento de Salud del Estado de Pernambuco, en la región metropolitana de Recife, Pernambuco, 2015. MÉTODOS: estudio epidemiológico descriptivo de serie de casos (reportados de 1 de agosto a 31 de octubre de 2015), con datos obtenidos de registros médicos y cuestionarios aplicados a las madres. RESULTADOS: 40 casos fueron confirmados con microcefalia, en ocho municipios de la región metropolitana de Recife, con mayor concentración de casos en Recife (n=12); la circunferencia media de la cabeza fue 29 cm, perímetro torácico 31 cm y peso 2.628 gramos; exámenes revelaron que 21/25 casos mostraron calcificación, dilatación ventricular o lisencefalia; de las 40 madres, 27 (68%) informan exantema durante la gestación, 20 (74%) en el primer trimestre y siete (26%) en la segunda, además de prurito, dolor de cabeza, mialgia y ausencia de fiebre. CONCLUSIÓN: la mayoría de los casos presenta características de infección congénita; la mayoría de las madres mostró características que sugieren infección por el virus Zika en el embarazo.

OBJECTIVE: to describe the first cases of microcephaly possibly related to Zika virus in live born babies reported in the Metropolitan Region of Recife, Pernambuco State, Brazil. METHODS: this was a descriptive case series study (cases reported between August 1st and October 31st 2015), using medical record data and data from a questionnaire answered by the mothers of the babies. RESULTS: 40 microcephaly cases were confirmed, distributed in eight municipalities within the Metropolitan Region, with Recife itself having the highest concentration of cases (n=12); median head circumference was 29 cm, median chest girth was 31 cm and median weight was 2,628 grams; 21/25 cases had brain calcification, ventriculomegaly or lissencephaly; 27 of the 40 mothers reported rash during pregnancy, 20 in the first trimester and 7 in the second trimester, as well as itching, headache, myalgia and absence of fever. CONCLUSION: the majority of the cases bore the characteristics of congenital infection; the clinical condition of the majority of mothers suggested Zika virus infection during pregnancy.

Characteristics of the first cases of microcephaly possibly related to Zika virus reported in the Metropolitan Region of Recife, Pernambuco State, Brazil. / Características dos primeiros casos de microcefalia possivelmente relacionados ao vírus Zika notificados na Região Metropolitana de Recife, Pernambuco.

OBJECTIVE: to describe the first cases of microcephaly possibly related to Zika virus in live born babies reported in the Metropolitan Region of Recife, Pernambuco State, Brazil. METHODS: this was a descriptive case series study (cases reported between August 1st and October 31st 2015), using medical record data and data from a questionnaire answered by the mothers of the babies. RESULTS: 40 microcephaly cases were confirmed, distributed in eight municipalities within the Metropolitan Region, with Recife itself having the highest concentration of cases (n=12); median head circumference was 29 cm, median chest girth was 31 cm and median weight was 2,628 grams; 21/25 cases had brain calcification, ventriculomegaly or lissencephaly; 27 of the 40 mothers reported rash during pregnancy, 20 in the first trimester and 7 in the second trimester, as well as itching, headache, myalgia and absence of fever. CONCLUSION: the majority of the cases bore the characteristics of congenital infection; the clinical condition of the majority of mothers suggested Zika virus infection during pregnancy.

Assessment of the non-protein amino acid BMAA in Mediterranean mussel Mytilus galloprovincialis after feeding with estuarine cyanobacteria.

To determine whether 2-amino-3-methylaminopropanoic acid (BMAA) could be taken up by marine organisms from seawater or their diet mussels Mytilus galloprovincialis, collected from the North Atlantic Portuguese shore, were exposed to seawater doped with BMAA standard (for up to 48 h) or fed with cyanobacteria (for up to 15 days). Mussels were able to uptake BMAA when exposed to seawater. Mussels fed with cyanobacteria Synechocystis salina showed a rise in BMAA concentration during feeding and a decline in concentration during the subsequent depuration period. Cells from the gills and hepatopancreas of mussels fed with S. salina showed lessened metabolic activity in mussels fed for longer periods of time. A hot acidic digestion (considered to account for total BMAA) was compared with a proteolytic digestion, using pepsin, trypsin and chymotrypsin. The latter was able to extract from mussels approximately 30% of total BMAA. Implications for BMAA trophic transfers in marine ecosystems are discussed.

Global patterns and predictors of fish species richness in estuaries.

1. Knowledge of global patterns of biodiversity and regulating variables is indispensable to develop predictive models. 2. The present study used predictive modelling approaches to investigate hypotheses that explain the variation in fish species richness between estuaries over a worldwide spatial extent. Ultimately, such models will allow assessment of future changes in ecosystem structure and function as a result of environmental changes. 3. A comprehensive worldwide data base was compiled of the fish assemblage composition and environmental characteristics of estuaries. Generalized Linear Models were used to quantify how variation in species richness among estuaries is related to historical events, energy dynamics and ecosystem characteristics, while controlling for sampling effects. 4. At the global extent, species richness differed among marine biogeographic realms and continents and increased with mean sea surface temperature, terrestrial net primary productivity and the stability of connectivity with a marine ecosystem (open vs. temporarily open estuaries). At a smaller extent (within a marine biogeographic realm or continent), other characteristics were also important in predicting variation in species richness, with species richness increasing with estuary area and continental shelf width. 5. The results suggest that species richness in an estuary is defined by predictors that are spatially hierarchical. Over the largest spatial extents, species richness is influenced by the broader distributions and habitat use patterns of marine and freshwater species that can colonize estuaries, which are in turn governed by history contingency, energy dynamics and productivity variables. Species richness is also influenced by more regional and local parameters that can further affect the process of community colonization in an estuary including the connectivity of the estuary with the adjacent marine habitat, and, over smaller spatial extents, the size of these habitats. In summary, patterns of species richness in estuaries across large spatial extents seem to reflect from global to local processes acting on community colonization. The importance of considering spatial extent, sampling effects and of combining history and contemporary environmental characteristics when exploring biodiversity is highlighted.

Microbiological and mycological beach sand quality in a volcanic environment: Madeira archipelago, Portugal.

Madeira forms a mid-Atlantic volcanic archipelago, whose economy is largely dependent on tourism. There, one can encounter different types of sand beach: natural basaltic, natural calcareous and artificial calcareous. Microbiological and mycological quality of the sand was analyzed in two different years. Bacterial indicators were detected in higher number in 2010 (36.7% of the samples) than in 2011 (9.1%). Mycological indicators were detected in a similar percentage of samples in 2010 (68.3%) and 2011 (75%), even though the total number of colonies detected in 2010 was much higher (827 in 41 samples) than in 2011 (427 in 66 samples). Enterococci and potentially pathogenic and allergenic fungi (particularly Penicillium sp.) were the most common indicators detected in both years. Candida sp. yeast was also commonly detected in the samples. The analysis of the 3rd quartile and maximum numbers of all indicators in samples showed that artificial beaches tend to be more contaminated than the natural ones. However, a significant difference between the variables was lacking. More monitoring data (number of bathers, sea birds, radiation intensity variation, and a greater number of samples) should be collected in order to confirm if these differences are significant. In general, the sand quality in the archipelago's beaches was good. As the sand may be a vector of diseases, an international common set of indicators and values and a compatible methodologies for assessing sand contamination, should be defined, in order to provide the bather's with an indication of beach sand quality, rather than only the water.

Teleradiology based CT colonography to screen a population group of a remote island; at average risk for colorectal cancer.

PURPOSE: To prospectively assess the performance of teleradiology-based CT colonography to screen a population group of an island, at average risk for colorectal cancer. MATERIALS AND METHODS: A cohort of 514 patients living in Madeira, Portugal, was enrolled in the study. Institutional review board approval was obtained and all patients signed an informed consent. All patients underwent both CT colonography and optical colonoscopy. CT colonography was interpreted by an experienced radiologist at a remote centre using tele-radiology. Per-patient sensitivity, specificity, positive (PPV) and negative (NPV) predictive values with 95% confidence intervals (95%CI) were calculated for colorectal adenomas and advanced neoplasia ≥6 mm. RESULTS: 510 patients were included in the study. CT colonography obtained a per-patient sensitivity, specificity, PPV and, NPV for adenomas ≥6 mm of 98.11% (88.6-99.9% 95% CI), 90.97% (87.8-93.4% 95% CI), 56.52% (45.8-66.7% 95% CI), 99.75% (98.4-99.9% 95% CI). For advanced neoplasia ≥6 mm per-patient sensitivity, specificity, PPV and, NPV were 100% (86.7-100% 95% CI), 87.07% (83.6-89.9% 95% CI), 34.78% (25.3-45.5% 95% CI) and 100% (98.8-100% 95% CI), respectively. CONCLUSION: In this prospective trial, teleradiology-based CT colonography was accurate to screen a patient cohort of a remote island, at average risk for colorectal cancer.

Assessing food web dynamics and relative importance of organic matter sources for fish species in two Portuguese estuaries: a stable isotope approach.

Stable carbon and nitrogen isotopes (δ¹³C, δ¹5N) were used to analyse food web dynamics of two of the main estuaries of the Portuguese coast: Tejo and Mira. The ultimate sources of organic matter supporting production of some of the most abundant and commercially important fish species were determined; and seasonal, inter- and intra- estuarine differences in the trophic relations among producers and consumers were identified. Stable isotope analysis was performed in different producers, primary consumers (main prey items for fish) and fish species (Solea solea, Solea senegalensis, Pomatoschistus microps, Dicentrarchus labrax, Liza ramada, Diplodus vulgaris and Atherina presbyter) of two areas in each estuary, in July and October 2009. Model calculations showed that the main prey for the fish species in the Tejo estuary used mostly salt marsh-derived organic matter as nutritional sources, with no marked differences between the sampled months. Trophic levels of fish species from the same estuary differed at multiple scales: inter-species, seasonally and spatially (both between and within estuaries). Significant differences in isotopic composition of fish species were more pronounced spatially (between the two sampled areas in the estuary) than seasonally (between sampled months). Trophic relationships in both estuaries demonstrated that organic matter is transferred to higher trophic positions mainly through benthic pathways. This shows the flexibility of these species to share resources and to exploit temporary peaks in prey populations. The present results showed that extensive disturbance in intertidal habitats from both estuaries may potentially change the balance of organic matter in the base of these complex food webs.

Selecting statistical models and variable combinations for optimal classification using otolith microchemistry.

Reliable assessment of fish origin is of critical importance for exploited species, since nursery areas must be identified and protected to maintain recruitment to the adult stock. During the last two decades, otolith chemical signatures (or "fingerprints") have been increasingly used as tools to discriminate between coastal habitats. However, correct assessment of fish origin from otolith fingerprints depends on various environmental and methodological parameters, including the choice of the statistical method used to assign fish to unknown origin. Among the available methods of classification, Linear Discriminant Analysis (LDA) is the most frequently used, although it assumes data are multivariate normal with homogeneous within-group dispersions, conditions that are not always met by otolith chemical data, even after transformation. Other less constrained classification methods are available, but there is a current lack of comparative analysis in applications to otolith microchemistry. Here, we assessed stock identification accuracy for four classification methods (LDA, Quadratic Discriminant Analysis [QDA], Random Forests [RF], and Artificial Neural Networks [ANN]), through the use of three distinct data sets. In each case, all possible combinations of chemical elements were examined to identify the elements to be used for optimal accuracy in fish assignment to their actual origin. Our study shows that accuracy differs according to the model and the number of elements considered. Best combinations did not include all the elements measured, and it was not possible to define an ad hoc multielement combination for accurate site discrimination. Among all the models tested, RF and ANN performed best, especially for complex data sets (e.g., with numerous fish species and/or chemical elements involved). However, for these data, RF was less time-consuming and more interpretable than ANN, and far more efficient and less demanding in terms of assumptions than LDA or QDA. Therefore, when LDA and QDA assumptions cannot be reached, the use of machine learning methods, such as RF, should be preferred for stock assessment and nursery identification based on otolith microchemistry, especially when data set include multispecific otolith signatures and/or many chemical elements.

Doença tireóidea no idoso: revisäo bibliográfica / Thyroid disease in aged: bibliographic review

O reconhecimento de desordens tireóideas na populaçao idosa em estágios precoces é crucial para reduzir a morbidade e a mortalidade. A interposiçao apropriada dos testes de funçao tireóidea é também importante, pela associaçao de desordens nao-tireóideas e o uso de drogas nos idosos, que freqüentemente alteram os resultados dos testes, mesmo no indivíduo eutireóideo. Finalmente, a terapia deve ser prontamente iniciada, mas com cuidado, com monitorizaçao estreita e freqüente, devido aos riscos da reposiçao hormonal no idoso.