How nematode morphometric attributes integrate with taxonomy-based measures along an estuarine gradient

Nematodes are highly susceptible to environmental change and possess a wide array of morphological and functional characteristics for the assessment of the “Good Environmental Status”, within Marine Strategy Framework Directive. However, while the taxonomic sufficiency of nematodes in detecting spatial gradients and related ecological niche conditions is well recognized, very little is known about nematodes functional morphometric attributes in response to environmental drivers. To explore this knowledge gap, we aimed to assess the efficacy and efficiency of nematode morphometric attributes (length, width, length/width ratio, biomass) in detecting spatial patterns along a Portuguese estuarine gradient, and compare it with the taxonomic approach. We hypothesized that abundance data weighted by the morphometric attributes will have a higher explanatory power in detecting spatial patterns than using abundance of morphometric data alone. Based on the recent recommendations regarding the time and cost related efficacy of methods in biomonitoring and ecological assessments we also hypothesized that a reduced dataset based on the most common genera will suffice to capture the same distributional patterns displayed by the whole assemblage. Our results demonstrated that dataset solely based on genera abundances had consistently better explanatory power than combined datasets or morphometric datasets alone, however, combined dataset provided different spatial patterns and performed better at discriminating estuary areas. The main gradients described by the taxonomy-based dataset were related to the sediment particle size and water depth. Considering combined datasets, spatial discrimination was mainly driven by the variation in dissolved oxygen % saturation, pointing out to the importance of this variable in determining estuarine conditions substantial for nematodes morphometric distributional patterns. The same analysis repeated for the most frequent genera resulted in similar distributional patterns as for the whole assemblage dataset, clearly demonstrating that spatial estuarine gradients can be sufficiently described by using only the most frequent genera. Such information may substantially increase the efficiency of bio-assessment surveys by reducing the cost and work associated with identification and measurements of all of the individual nematode genera

How nematode morphometric attributes integrate with taxonomy-based measures along an estuarine gradient

Nematodes are highly susceptible to environmental change and possess a wide array of morphological and functional characteristics for the assessment of the “Good Environmental Status”, within Marine Strategy Framework Directive. However, while the taxonomic sufficiency of nematodes in detecting spatial gradients and related ecological niche conditions is well recognized, very little is known about nematodes functional morphometric attributes in response to environmental drivers. To explore this knowledge gap, we aimed to assess the efficacy and efficiency of nematode morphometric attributes (length, width, length/width ratio, biomass) in detecting spatial patterns along a Portuguese estuarine gradient, and compare it with the taxonomic approach. We hypothesized that abundance data weighted by the morphometric attributes will have a higher explanatory power in detecting spatial patterns than using abundance of morphometric data alone. Based on the recent recommendations regarding the time and cost related efficacy of methods in biomonitoring and ecological assessments we also hypothesized that a reduced dataset based on the most common genera will suffice to capture the same distributional patterns displayed by the whole assemblage. Our results demonstrated that dataset solely based on genera abundances had consistently better explanatory power than combined datasets or morphometric datasets alone, however, combined dataset provided different spatial patterns and performed better at discriminating estuary areas. The main gradients described by the taxonomy-based dataset were related to the sediment particle size and water depth. Considering combined datasets, spatial discrimination was mainly driven by the variation in dissolved oxygen % saturation, pointing out to the importance of this variable in determining estuarine conditions substantial for nematodes morphometric distributional patterns. The same analysis repeated for the most frequent genera resulted in similar distributional patterns as for the whole assemblage dataset, clearly demonstrating that spatial estuarine gradients can be sufficiently described by using only the most frequent genera. Such information may substantially increase the efficiency of bioassessment surveys by reducing the cost and work associated with identification and measurements of all of the individual nematode genera.info:eu-repo/semantics/publishedVersio

A aprendizagem dos números racionais no ensino básico: Um estudo no 3º ano do 1º ciclo

O presente trabalho teve como principal objetivo, identificar quais foram as dificuldades dos alunos na aquisição de número racional no 1º ciclo do ensino básico, nomeadamente no que diz respeito ao seu desenvolvimento na forma de fração, à comparação e equivalência de frações e identificar metodologias que desenvolvessem a capacidade de resolução de problemas com números racionais. Para isso trabalhou-se simultaneamente com as várias representações dos números racionais nos diferentes significados, em diferentes contextos e tipos de grandeza, em tarefas de natureza diversa utilizando uma metodologia exploratória com especial atenção à natureza das tarefas e à sua comunicação matemática, querendo assim dar resposta à questão “Quais as representações que os alunos privilegiam na resolução de tarefas com números racionais?”. A metodologia utilizada neste estudo foi a de um estudo de caso, no entanto tratou-se de uma investigação-ação, sobre e para a prática, de natureza qualitativa, na qual foram identificadas as dificuldades dos participantes, elaborou-se uma proposta de plano de ação para colmatar as mesmas e fez-se uma nova análise do nível de conhecimentos dos alunos de forma a verificar se esse plano estava adequado, identificando-se assim as melhorias dos mesmos e lacunas ainda presentes. No entanto, uma vez que este estudo se realizou apenas numa turma específica, os resultados não podem ser generalizados. Os participantes desta investigação foram dezassete alunos de uma turma de 3º ano do 1º Ciclo do Ensino Básico. A investigação decorreu no ano letivo 2014/2015, na referida turma, onde decorreu a prática de ensino da autora deste estudo

Management Models of the Manila Clam (Ruditapes philippinarum) Fisheries in Invaded European Coastal Systems

The Manila clam (Ruditapes philippinarum, Adam & Reeve 1850) is a non-indigenous species that was introduced in Europe (France) in the 1970s for commercial purposes, and reached Portugal in the 1980s. Currently, it occurs in several European coastal systems, from the Bay of Biscay to the north Mediterranean. In Portugal, it is present in estuarine systems and coastal lagoons from the north to south, such as Ria de Aveiro, Óbidos Lagoon and Sado estuary, but a sharp rise in the prevalence of this species in the largest Portuguese estuary, the Tagus, resulted in the exponential growth of the number of harvesters and, consequently, an increase in the illegal exploitation of this resource. At least 1700 harvesters were estimated in this system and an annual catch volume of between around 4,000 and 17,000 t which corresponds to an annual value around €10,000,000 to €23,000,000 of sales. There is a general failure to comply with current legislation, both in relation to harvesting and marketing, as well as constraints arising from spatial planning instruments in force on the estuary. The failure to comply with sanitary standards for the exploitation and trade of bivalve mollusks presents a risk to public health and a social-economic issue resulting from this activity. The goal of this study is to propose management models for this activity with the aim of contributing to create a legal framework in which sustainable harvesting can be achieved, in the different systems where exploitation occurs. In order to accomplish this goal, the current state play, legal framework, regulation for harvesting and trade and relevant spatial planning instruments in Portugal are analyzed. In order to ascertain an adequate national management strategy, a variety of case studies in France, Spain and Italy were studied. The outcome is a management model which includes a co-management strategy of concessions as well as a mixed regime with concession areas and free areas. The creation of specific regulations; implementation of a co-management model with the active participation of harvesters; science-based regulation of a closed season and maximum daily quotas and an improved surveillance of the activity are recommended.info:eu-repo/semantics/publishedVersio

Age and growth of a highly successful invasive species: the Manila clam Ruditapes philippinarum (Adams & Reeve, 1850) in the Tagus Estuary (Portugal)

The Manila clam Ruditapes philippinarum (Adams & Reeve, 1850) was introduced in several regions worldwide where it is permanently established. In Portuguese waters, the colonisation of the Tagus Estuary by this invasive species coincided with a significant decrease in abundance of the native Ruditapes decussatus (Linnaeus, 1758). This study aimed to estimate the age and growth of the Manila clam, to compare the growth performance between R. philippinarum and R. decussatus in several locations worldwide, and to ascertain whether the Manila clam's growth patterns contributed to the extensive distribution of this invasive bivalve in the Tagus Estuary. The growth of R. philippinarum in the Tagus Estuary was described through the von Bertalanffy equation SLt=65.2[1-e(-0.34(t+0.93))],corresponding to a phi-prime index (phi') of 3.160 and an overall growth performance of 4.974. This growth performance is the second highest recorded for R. philippinarum worldwide and was much higher than that of R. decussatus from Portugal. This study confirmed that the Tagus Estuary presents near-ideal environmental conditions for growth of the Manila clam. R. philippinarum displayed clearly invasive behaviour, spreading widely and growing faster than the native R. decussatus, which certainly contributed to the decline of its populations in the Tagus Estuary.Fundacao para a Ciencia e Tecnologia (FCT Portugal) [SFRH/BPD/26348/2006]; project "Ameijoajaponesa - estado actual da populacao do estuario do Tejo, impactos e gestao da apanha"; Fisheries Operational Programme (PROMAR); European Fisheries Fund (EFF); strategic plan of MARE - Marine and Environmental Sciences Centre [UID/MAR/04292/2013]; FCT [UID/Multi/04326/2013

Multi-element profiles as a fingerprint to discriminate estuarine R. philippinarum populations.

Filter-feeder bivalves such as non-indigenous Ruditapes philippinarum absorb and accumulate metals, resulting in multi-element signatures. The goal of this study was to analyse if multi-element profiles of R. philippinarum can discriminate between spatial and temporal patterns of estuarine bivalves’ populations. Spatial and temporal variability patterns of chemical profiles were assessed by collecting samples of R. philippinarum and sediment at i) three sites with different environmental and physiological conditions of clams, ii) located within two Portuguese estuaries (Tagus and Sado estuaries) and iii) sampled at three different occasions (May 2018, January 2019, May 2019). This sampling design hypothesized that there are significant differences in the bivalves’ chemical profiles between estuaries, among sampling sites and among sampling occasions. The chemical elements were categorized according to the estuarine geomorphology sources (Se,Co, Ni and Cu), elements with function in metabolic processes of the clams (Mn, Fe, Zn and Cr) and elements derived from the anthropogenic inputs (As, Pb and Cd). The multielement concentrations of clams’ soft tissues and sediments were obtained using a powerful analytical technique, ICP-MS (inductively coupled plasma mass spectrometry). Multivariate differences were tested in multi-element concentrations of bivalves’ soft tissues and sediments. Results revealed that Zn, Co, Ni and Pb were the main contributors for the chemical signatures of Tagus estuary populations, whilst for the Sado estuary populations were Cu, Fe, Cr, As and Cd. These elements were representative of all elemental categories and proved to be spatial and temporal habitat discriminators of bivalves’ estuarine populations. The multi-element signatures of R. philippinarum as a natural tag derived from the physical and chemical conditions of its habitat can be considered as a potential rapid tool for ecological biomonitoring and habitat assessment, accounting for spatial and temporal habitat differences of estuarine populations

On the Atlantic blue crab (Callinectes sapidus Rathbun 1896) in southern European coastal waters: Time to turn a threat into a resource?

[EN] The blue crab Callinectes sapidus is native to the coastal waters of the western Atlantic Ocean, and along the US coasts the species supports an important fishery. The crab was introduced to Europe at the beginning of the 20th century. To date, the species is considered invasive and it has been extensively recorded in southern European waters (SEW), where it is starting to penetrate the shellfish market. Here, an integrated management strategy is proposed for the blue crab in SEW, including the Mediterranean and Black Sea and the eastern Atlantic coasts of the Iberian Peninsula. Taking as introductory examples two case studies represented by the red king crab Paralithodes camtschaticus and the green crab Carcinus maenas, a framework of key issues is reviewed, considering the double nature of the species as invaders and shellfish products. A SWOT analysis is eventually presented for C. sapidus, in order to perform a state-of-the-art synthesis of the proposed scenario, highlighting the potential opportunities as well as the weaknesses related with the limited knowledge of the ecological and economic impact of the species in invaded habitats. The review is concluded by an appraisal of the current trends in global and European crustacean fisheries. The ongoing expansion of C. sapidus might represent a useful management case study, where the need to control an invasive species and mitigate its ecological impact can be harmonized with the opportunity to value it as a fishery resource.Funding from FUR 2013-2014 and 2015-2016 to G. M. is acknowledged. The European Fisheries Fund (FEP) Puglia Region (Italy) supported L. C. (CIP 04/OPI/010). The Portuguese Science Foundation (FCT) supported F. R. (SFRH/BPD/46761/2008). F. R. and P. C. were also supported by the strategic MARE plan Marine and Environmental Sciences Centre (UID/MAR/04292/2013). Constructive comments from two anonymous reviewers on an earlier version of the paper are gratefully acknowledged. This paper is dedicated to Sofia Mancinelli, thy eternal summer shall not fade.Mancinelli, G.; Chainho, P.; Cilenti, L.; Falco, S.; Kapiris, K.; Katselis, G.; Ribeiro, F. (2017). On the Atlantic blue crab (Callinectes sapidus Rathbun 1896) in southern European coastal waters: Time to turn a threat into a resource?. Fisheries Research. 194:1-8. https://doi.org/10.1016/j.fishres.2017.05.002S1819

CoastNet Dataset From Mondego, Tejo and Mira Estuaries: Multiparametric Measurements During 2020

info:eu-repo/semantics/publishedVersio

Age and growth of a highly successful invasive species: the Manila clam Ruditapes philippinarum (Adams & Reeve, 1850) in the Tagus Estuary (Portugal)

The Manila clam Ruditapes philippinarum (Adams & Reeve, 1850) was introduced in several regions worldwide where it is permanently established. In Portuguese waters, the colonisation of the Tagus Estuary by this invasive species coincided with a significant decrease in abundance of the native Ruditapes decussatus (Linnaeus, 1758). This study aimed to estimate the age and growth of the Manila clam, to compare the growth performance between R. philippinarum and R. decussatus in several locations worldwide, and to ascertain whether the Manila clam's growth patterns contributed to the extensive distribution of this invasive bivalve in the Tagus Estuary. The growth of R. philippinarum in the Tagus Estuary was described through the von Bertalanffy equation SLt=65.2[1-e(-0.34(t+0.93))],corresponding to a phi-prime index (phi') of 3.160 and an overall growth performance of 4.974. This growth performance is the second highest recorded for R. philippinarum worldwide and was much higher than that of R. decussatus from Portugal. This study confirmed that the Tagus Estuary presents near-ideal environmental conditions for growth of the Manila clam. R. philippinarum displayed clearly invasive behaviour, spreading widely and growing faster than the native R. decussatus, which certainly contributed to the decline of its populations in the Tagus Estuary.Fundacao para a Ciencia e Tecnologia (FCT Portugal) [SFRH/BPD/26348/2006]; project "Ameijoajaponesa - estado actual da populacao do estuario do Tejo, impactos e gestao da apanha"; Fisheries Operational Programme (PROMAR); European Fisheries Fund (EFF); strategic plan of MARE - Marine and Environmental Sciences Centre [UID/MAR/04292/2013]; FCT [UID/Multi/04326/2013

Community perceptions about mangrove ecosystem services and threats

The Ecosystem Service Framework discloses the ecosystem’s benefits to society and provides support to preserve threatened systems while considering the economic and social dimensions of the communities more dependent on its resources. Mangroves provide important and valuable goods and services to communities, at different spatial and temporal scales. Nevertheless, over-exploitation of these resources can generate poverty traps, where rural households can no longer use the ecosystem as a source of food security or income. This study uses three communities that live in surrounding areas of mangroves from São Tomé Island (Diogo Nunes, Angolares, and Malanza) as a case study. The main aim was to evaluate locals’ perspectives about ecosystem use, threats, and conservation. Questionnaires were conducted among local populations and provided valuable information to identify the major beneficiaries of mangrove resources. These results also indicated that the services and threats identified locally are different from those identified in the literature. The importance of considering the impact of local values and traditions in the use of ecosystem resources was also highlighted by the obtained results since São Tomé residents do not acknowledge the existence of services that do not bring a direct benefit. The absence of awareness about mangroves and their threats can cause severe damages to the ecosystem’s health, requiring the implementation of specific awareness-raising policies among populations that interact with mangrove ecosystems.info:eu-repo/semantics/publishedVersio