Immigration and early life stages recruitment of the European flounder (Platichthys flesus) to an estuarine nursery: the influence of environmental factors

Connectivity between coastal spawning grounds and estuarine nurseries is a critical step in the life cycle of many fish species. Larval immigration and transport-associated physical–biological processes are determinants of recruitment success to nursery areas. The recruitment of the European flounder, Platichthys flesus, to estuarine nurseries located at the southern edge of the species distribution range, has been usually investigated during its juvenile stages, while estuarine recruitment during the earlier planktonic life stage remains largely unstudied. The present study investigated the patterns of flounder larval recruitment and the influence of environmental factors on the immigration of the early life stages to the Lima estuary (NW Portugal), integrating data on fish larvae and post-settlement individuals (< 50 mm length), collected over 7 years. Late-stage larvae arrived at the estuary between February and July and peak abundances were observed in April. Post-settlement individuals (< 50 mm) occurred later between April and October, whereas newly-settled ones (< 20 mm) were found only in May and June. Variables associated with the spawning, survival and growth of larvae in the ocean (sea surface temperature, chlorophyll a and inland hydrological variables) were the major drivers of flounder occurrence in the estuarine nursery. Although the adjacent coastal area is characterized by a current system with strong seasonality and mesoscale variability, we did not identify any influence of variables related with physical processes (currents and upwelling) on the occurrence of early life stages in the estuary. A wider knowledge on the influence of the coastal circulation variability and its associated effects upon ocean-estuarine connectivity is required to improve our understanding of the population dynamics of marine spawning fish that use estuarine nurseries

Nuevos aspectos sobre la ecología de los estados iniciales de desarrollo de Sardina pilchardus (Walbaum, 1792) en el norte del Atlántico ibérico

In the Atlantic Iberian estuaries, sardines tend to be a minor component of the ichthyoplankton assemblages, with rare occurrence largely restricted to estuarine mouths. However, this was not the case of the Lima estuary (NW Portugal), where sardines were the most abundant and frequently occurring marine taxon of the larval fish assemblages. Abundance of sardines collected during a two-year survey (2002-2004) ranged from 0.5 to 60.8 larvae/100 m3, with the majority still showing yolk and unpigmented eyes. Moreover, 80% of sardines were 8 days old or less and the total length ranged from 2 to 16 mm. Seasonal variations of sardine occurrence in the Lima estuary correlated with temporal variations of salinity and temperature in the water column. The unusually high river-flow observed during the winter of 2002-2003, which preceded the spring-summer abundance peak, seemed to act as a signal for the estuarine recruitment that was encountered. In addition, the estuarine occurrence of sardine larvae was also correlated with the intensity of summer upwelling, which was responsible for coastal depletion of sardine larvae resulting in estuarine low catches during the summer of 2002. The Lima estuary also revealed another peculiarity related to the lack of temporal synchrony between coastal spawning activity and occurrence of larvae within the estuary. The abundance peaks of newly-hatched larvae (autumn 2002 and spring-summer 2003) did not coincide with the winter-spring spawning pattern described earlier for the northern Iberian coast. Modifications of the spawning strategy of the northern Iberian sardine stock are discussed based on these new insights into the early life of S. pilchardus.Las sardinas tienden a ser un componente menor del ictioplancton de los estuarios atlánticos ibéricos. Su aparición es rara y restringida, en gran parte, a las desembocaduras de los ríos. Sin embargo, éste no fue el caso del estuario del río Lima (NW Portugal), donde las sardinas fueron la especie marina más abundante del ictioplanton estuarino. Las sardinas fueron recolectadas durante un período de dos años (2002-2004), y su abundancia varió entre 0.5-60.8 larvas/100 m3. La mayoría de dichas larvas todavía presentaban saco vitelino y ojos no pigmentados. Por otra parte, el 80% de las sardinas tenían 1 semana o menos de vida y su longitud total varió entre 2 y 16 mm. Las variaciones estacionales en la aparición de larvas de sardina en el estuario del río Lima se correlacionaron con fluctuaciones temporales de salinidad y de temperatura de la columna de agua. Los elevados caudales del río observados durante el invierno 2002-2003, que precedieron el pico de abundancia del primavera-verano, parecieron actuar como señal para el reclutamiento al estuario. Además, la aparición en el estuario de larvas de sardina también fue controlada por la intensidad del afloramiento de verano, responsable de la disminución de abundancia de larvas de sardina en la costa, lo que dio lugar a bajas capturas en el estuario durante el verano 2002. Además la inusual aparición de larvas de sardina, dentro del estuario del río Lima reveló otra particularidad relacionada con la carencia de sincronía temporal entre la actividad de freza y la aparición de larvas dentro del estuario. Los picos de abundancia de larvas recién eclosionadas (otoño 2002 y período de primavera-verano de 2003) no coincidieron con la época de puesta invernal previamente descrita para la costa norte de la península ibérica. Estos nuevos datos sobre la ecología de los estados iniciales de desarrollo de la sardina se discuten a la luz de las modificaciones de la estrategia reproductiva del stock de sardinas del norte del Atlántico ibérico

Monitoring glucose, calcium, and magnesium levels in saliva as a non-invasive analysis by sequential injection multiparametric determination

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Endemic goiter and iodine deficiency status among Guinea-Bissau school-age children

Background/objectives Iodine deficiency disorders are estimated to affect 25% of all school-age children around the world. Current policies concerning iodine deficiency disorders in many countries are not based on robust or recent national data. Our objective was to evaluate the current status of iodine nutrition in Guinea-Bissau (West Africa).Subject/methods A cross-sectional survey including 299 school-age children, aged 6-14 years old, from four distinct regions of Guinea-Bissau across a coast-hinterland gradient (Bolama, Bissau, Cambaju-Bafata, and Gabil) was performed. Several iodine deficiency disorders indicators were used: total goiter rate, median urinary iodine concentration (UIC) and regional iodine content in household salt and drinking water samples. Data on the total goiter rate were obtained by thyroid ultrasound.Results Goiter was found in 73.5% (CI 95%, 68.5-78.2%) of the school-age children. We observed a median urinary iodine concentration of 110 mcg/l, with 7.3% of the studied population presenting urinary iodine concentration = 15 mg/kg. Median well water iodine concentration was 11.7 mcg/l.Conclusions Guinea-Bissau presents high rates of goiter in school-age children despite satisfactory median urinary iodine concentration population levels. Salt and drinking water iodine median content cannot explain these findings. Further studies following the progress in iodine deficiency status and the presence of potential goitrogens in diet of this vulnerable population are in needed.(undefined)info:eu-repo/semantics/publishedVersio

Habitat loss and gain: Influence on habitat attractiveness for estuarine fish communities

© 2017 Elsevier Ltd Habitat structure and complexity influence the structuring and functioning of fish communities. Habitat changes are one of the main pressures affecting estuarine systems worldwide, yet the degree and rate of change and its impact on fish communities is still poorly understood. In order to quantify historical modifications in habitat structure, an ecohydrological classification system using physiotopes, i.e. units with homogenous abiotic characteristics, was developed for the lower Lima estuary (NW Portugal). Field data, aerial imagery, historical maps and interpolation methods were used to map input variables, including bathymetry, substratum (hard/soft), sediment composition, hydrodynamics (current velocity) and vegetation coverage. Physiotopes were then mapped for the years of 1933 and 2013 and the areas lost and gained over the 80 years were quantified. The implications of changes for the benthic and demersal fish communities using the lower estuary were estimated using the attractiveness to those communities of each physiotope, while considering the main estuarine habitat functions for fish, namely spawning, nursery, feeding and refuge areas and migratory routes. The lower estuary was highly affected due to urbanisation and development and, following a port/harbour expansion, its boundary moved seaward causing an increase in total area. Modifications led to the loss of most of its sandy and saltmarsh intertidal physiotopes, which were replaced by deeper subtidal physiotopes. The most attractive physiotopes for fish (defined as the way in which they supported the fish ecological features) decreased in area while less attractive ones increased, producing an overall lower attractiveness of the studied area in 2013 compared to 1933. The implications of habitat alterations for the fish using the estuary include potential changes in the nursery carrying capacity and the functioning of the fish community. The study also highlighted the poor knowledge of the impacts of habitat changes on fish due to coastal development and urbanisation and emphasises that ecosystem management and conservation will benefit from a wider understanding of habitat functional roles and habitat changes influencing the functioning and structure of the fish communities

Improvement of the Sandell-Kolthoff reaction method (ammonium persulfate digestion) for the determination of iodine in urine samples

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Paper-Based Biosensors for Analysis of Water

The presence of contaminants in water generates a great concern worldwide. As contaminants, we can refer different classes of chemicals, such as pharmaceuticals, personal care products, heavy metals, and also microorganisms, such as waterborne pathogens. Some of the chemical compounds have the potential to bioaccumulate in the aquatic biota. Hence, the development of simple and portable methods for the detection of contaminants in the aquatic environment can improve their monitoring and, consequently, the study of their environmental impact. In this context, the development of paper-based analytical tools and also of biosensor devices has been exploited for quantitative and semiquantitative analysis of several contaminants in different water matrices. The association of these two analytical strategies can provide the implementation of low-cost, portable, and easily handled methods for detecting chemical and biological contaminations in water. In this chapter, we provide a review of the developed paper-based analytical biosensors, highlighting the features of the paper-based (paper substrate and fabrication procedures) and biosensor devices (transducers and biorecognition elements). Moreover, the application of the referred paper-based biosensors for the detection of different water contaminants (pathogens, pharmaceuticals, and heavy metals) in environmental and wastewater samples is discussed

Screening of fluoroquinolones in environmental waters using disk-based solid-phase extraction combined to microplate fluorimetric determination and LC-MS/MS

Fluoroquinolones are in the order of the day concerning environmental contamination through anthropogenic activities, resulting in increased risk for antibiotic resistance dissemination. In this context, accessible, low-cost analytical methods are required for implementation of comprehensive surveillance and screening schemes. In this work, we propose a down-scaled disk-based solid-phase extraction system from which the eluate can be first screened by miniaturized fluorimetric reading, followed by individual determination of target fluoroquinolones (ciprofloxacin, norfloxacin, and enrofloxacin) by liquid chromatography combined to tandem mass spectrometry. The fluorimetric measurement is based on the intrinsic fluorescence of fluoroquinolones. Disk-based retention was performed after sample acidification (pH 4.0) by mixed-mode cation exchange using polystyrene divinylbenzene sulphonated sorbent. Sample loading was precisely controlled in a dedicated flow system operating at 4.0 mL min−1. Different eluent compositions were tested, with elution performed by 1.00 mL of methanol-ammonium hydroxide (98:2, v/v), with subsequent reading of eluate in both detectors. Quantification was attained for 2–25 µg L−1 range, with LOD values at 1 µg L−1. The proposed approach was successfully applied to estuarine waters from the Douro River, with comparable results to a conventional SPE-LC-MS/MS procedure.info:eu-repo/semantics/publishedVersio