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Scientific tools capable of identifying distribution patterns of species are important as they contribute to improve knowledge about biodiversity and species dynamics. The present study aims to estimate the spatiotemporal distribution of sardine (Sardina pilchardus, Walbaum 1792) in the Portuguese continental waters, relating the spatiotemporal variability of biomass index with the environmental conditions. Acoustic data was collected during Portuguese spring acoustic surveys (PELAGO) over a total of 16,370 hauls from 2000 to 2020 (gap in 2012). We propose a spatiotemporal species distribution model that relies on a two-part model for species presence and biomass under presence, such that the biomass process is defined as the product of these two processes. Environmental information is incorporated with time lags, allowing a set of lags with associated weights to be suggested for each explanatory variable. This approach makes the model more complete and realistic, capable of reducing prediction bias and mitigating outliers in covariates caused by extreme events. In addition, based on the posterior predictive distributions obtained, we propose a method of classifying the occupancy areas by the target species within the study region. This classification provides a quite helpful tool for decision makers aiming at marine sustainability and conservation. Supplementary materials accompanying this paper appear on-line. [ABSTRACT FROM AUTHOR]

According to the principles of community ecology, sympatric species may suffer a selective pressure to decrease their niche overlap through mechanisms of niche partitioning. However, there is still a gap in knowledge of the main drivers influencing niche differentiation, particularly in communities composed by small-sized and inconspicuous species. The coastal epipelagic community structure of mid-trophic level species in the Northeast Atlantic was examined using stable isotope analysis to (1) decipher intrinsic and extrinsic factors promoting niche partitioning and (2) examine species divergence in the use of resources. A total of 474 individuals from a guild of 11 species were sampled during three years, and the influence of potential drivers of isotopic divergence was assessed. The niche partitioning was mainly determined by the taxonomic group in accordance with the fundamental principles of niche theory, which was consistent for both δ13C (i.e. habitat) and δ15N (i.e. prey). Body size was highly important in driving niche partitioning within species. Our results show that the predominant species in the guild were the most generalist, when compared with more specialised species with which they coexist. This study reveals that the intrinsic factors are determinant to decrease inter- and intra-specific niche overlap at the community level. [ABSTRACT FROM AUTHOR]

Hyperglycaemia first detected during pregnancy is either gestational diabetes mellitus (GDM) or previous undiagnosed diabetes. We aimed to study if there were a first trimester fasting glycaemia (FTG) and a glycated haemoglobin (HbA1c) cut-off values associated with type 2 diabetes mellitus (T2DM) or abnormal glucose homeostasis (AGH) at the post-partum oral glucose tolerance test (OGTT) reclassification. We retrospectively studied a group of pregnant women from the Portuguese National Registry of GDM. Receiver-operating characteristic (ROC) curves were used to determine the best FTG and HbA1c cut-offs to predict T2DM and AGH. We studied 4068 women. The area under the ROC curves (AUC) for the association with T2DM was 0.85 (0.80–0.90) for FTG and 0.85 (0.80–0.91) for HbA1c. The best FTG cut-off for association with T2DM was 99 mg/dL: sensitivity 77.4%, specificity 74.3%, positive predictive value (PPV) 4.8%, and negative predictive value (NPV) 99.5%. The best HbA1c cut-off for association with T2DM was 5.4%: sensitivity 79.0%, specificity 80.1%, PPV 5.7%, and NPV 99.6%. The AUC for the association of FTG and HbA1c with AGH were 0.73 (0.70–0.76) and 0.71 (0.67–0.74), respectively. The best FTG cut-off for predicting AGH was 99 mg/dL: sensitivity 59.4%, specificity 76.2%, PPV 17.0%, and NPV 95.8%. The best HbA1c cut-off was 5.4%: sensitivity 48.7%, specificity 81.5%, PPV 17.8%, and NPV 95.1%. We suggest an FTG of 99 mg/dL and an HbA1c of 5.4% as the best cut-offs below which T2DM is unlikely to be present. Almost all patients with FTG < 99 mg/dL and HbA1c < 5.4% did not reclassify as T2DM. These early pregnancy cut-offs might alert the physician for the possibility of a previous undiagnosed diabetes and alert them to the importance of testing for it after delivery. [ABSTRACT FROM AUTHOR]

Aim: Metformin use in gestational diabetes (GDM) is a common practice. Although its use in combination with insulin might be advantageous, it was never formally tested. We studied whether combined treatment was associated with better obstetric or neonatal outcomes compared to insulin alone. Methods: This is a retrospective study, using the Portuguese National Registry of GDM (2012–2017), of women treated with insulin ± metformin. Primary endpoints were obstetric and neonatal complications. Secondary endpoints were gestational weight gain (GWG) and insulin dose. A propensity score-matched analysis was performed to balance the distribution of age, BMI, insulin treatment duration, HbA1c, first trimester diagnosis of GDM and previous GDM or macrosomia. Women treated with metformin plus insulin and insulin only were then compared. Results: A total of 4034 women were treated with insulin or insulin plus metformin (10.2%). After propensity score matching, we studied two groups of 386 patients. Obstetric and neonatal complications were similar. Women treated with metformin plus insulin had 201 (52.1%) obstetric complications versus 184 (47.7%) in insulin-only group, p = 0.22; and 112 (29.0%) neonatal complications versus 96 (24.9%), p = 0.19. Patients treated with metformin plus insulin had similar GWG, excessive weight gain and insulin dose compared to the insulin-only group. Conclusions: Women with GDM treated with insulin plus metformin had similar obstetric and neonatal complications, weight gained and insulin dose compared to those only treated with insulin. [ABSTRACT FROM AUTHOR]

Little is known regarding the swimming ability of the larvae of European plaice ( Pleuronectes platessa) in relation to changes in total length (TL), dry weight (DW) and developmental stage, which is surprising given the importance of transport processes to the recruitment dynamics of this species in the North Sea and elsewhere. We investigated ontogenetic changes in the critical swimming speed ( U) of plaice from hatching to the onset of metamorphosis (50 days post-hatch, dph) at 8 °C. The mean (±SD) TL and DW growth rates were 1.59 ± 0.81 and 7.7 ± 0.35 % d, respectively. Larvae were unable to swim at against a minimum current speed of <0.5 cm s until 10 dph (7 mm TL), after which U significantly increased with increasing TL until the onset of metamorphosis and subsequent settlement. Mean (±SD) U was 0.38(0.35), 1.59(0.54), 2.27(0.49) and 2.99(0.37) cm s for stage I (6.61 ± 2.64 mm TL), stage II (7.75 ± 0.60 mm TL), stage III (9.10 ± 1.00 mm TL) and stage IV (11.59 ± 0.85 mm TL) larvae, respectively. Larval TL, DW, DNA content, RNA content and U significantly increased, whereas sRD significantly declined as larvae developed from stage I to V. Although inter-individual differences in U (coefficient of variation, CV = 33 %) were as large as those in biochemical and morphological condition (CV's of 21-42 %), differences in U were not significantly related to those in nutritional condition and larvae with lower DNA /DW had also better swimming abilities. These estimates should be useful to ongoing efforts to create individual-based models of the transport, foraging and growth of plaice larvae in the North Sea. [ABSTRACT FROM AUTHOR]

Temporal variation in the fatty acid (FA) composition of stomach contents of Iberian sardines was compared to the relative contribution to dietary carbon made by different prey types for fish from two areas off Portugal. The effect of the FA content of the diet on sardine muscle FA composition was also studied, aiming at (1) analysing if FA biomarkers can be used as a complementary technique for the study of sardine diet and (2) to relate spatial and temporal variations of prey FA content with sardine condition and reproduction. Significant spatial differences in the FA composition of sardine diet occurred with concentrations of n-3 polyunsaturated FA, namely eicosapentaenoic acid [EPA, 20:5n-3] and linolenic acid 18:3n-3, being significantly higher in the diet of sardines from the west coast, whilst the diet of sardines from the south coast was richer in monounsaturated fatty acids (MUFA), namely the carnivory biomarker oleic acid 18:1n-9. These results are in agreement with the higher contribution made by diatoms and dinoflagellates to the diet of sardines off the west coast. Spatial variation in sardine dietary FA was also detected in their muscle composition, specifically for EPA, and the eicosapentaenoic/docosahexaenoic acid and (n-3)/(n-6) ratios, which were higher in sardines from the west coast. No difference in FA composition was detected between sexes, and the seasonal variability in sardine total FA concentration was primarily related to the seasonality of spawning. Sardines accumulate high concentrations of FAs during the resting stage of reproduction when the feeding intensity is similar or lower to that observed during the spawning season. Additionally, sardines show a high selective retention of MUFA and polyunsaturated FA (PUFA) throughout the year except at the beginning of the spawning season, when these FAs are largely invested in the formation of the gonads. Therefore, temporal and regional differences of prey environments are strong enough to be reflected in fish body composition, namely on the accumulation of essential FAs, which can have a strong impact on reproduction success for this species. [ABSTRACT FROM AUTHOR]