UA01-Teses
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Percorrer UA01-Teses por Objetivos de Desenvolvimento Sustentável (ODS) "02:Erradicar a Fome"
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- Análise de métodos de classificação automática de uso do solo associadas à caracterização e quantificação de áreas regadas - Caso de estudo Campina de Faro, AlgarvePublication . Marques, Jonat Stefani Justa; Martins, Fernando Miguel Granja; Costa, Luís Ricardo Dias daA região Algarvia, com um clima temperado de características mediterrânicas, enfrenta uma crescente incidência de fenómenos de seca hidrológica prolongada, o que agrava de forma significativa os desafios relacionados com a escassez de recursos hídricos na região. A estimativa de valores do consumo de água subterrânea em áreas de regadio na região Algarvia consiste numa variável difícil de controlar e quantificar, não só devido ao elevado número de captações particulares, mas também por causa da variação meteorológica, que afeta os regimes de rega e das áreas regadas. Através da informação extraída pelo processamento de imagens digitais obtidas por deteção remota, juntamente com os valores das dotações de rega, pretende-se contribuir para estimativas do balanço hídrico do sistema aquífero de Campina de Faro mais precisas. Neste trabalho, estudou-se a classificação de uso e ocupação do solo para desenvolver uma metodologia de classificação automática de áreas agrícolas e espaços verdes regados, usando imagens de satélite Sentinel-2, aplicados à Campina de Faro. O projeto permitiu caracterizar com precisão as principais culturas agrícolas e espaços verdes regados na área de estudo e estimar o volume de água utilizado na rega com base nas dotações de rega das diferentes culturas. A metodologia desenvolvida é facilmente replicável para diferentes períodos e zonas, oferecendo uma ferramenta útil para a gestão dos recursos hídricos na região do Algarve. Os resultados obtidos permitiram a classificação das principais áreas e culturas regadas no sistema aquífero, bem como a quantificação da sua variação ao longo do tempo. Para além disso, foram aplicadas dotações de rega oficiais da DGADR, com o objetivo de estimar o volume de água utilizado na rega destas parcelas agrícolas, de forma a quantificar o volume de água extraído do aquífero para a agricultura e golfe. Os valores obtidos estão próximos dos valores oficiais reportados nos Planos de Gestão da Região Hidrográfica, o que demonstra, de certa forma, a fiabilidade dos resultados alcançados com esta metodologia.
- Blue shark distribution modelling in the North Atlantic: assessing projected overlap with longline fishing and climate change impactPublication . Dias, Carolina Mendes de Morais Gonçalves; Queiroz , Nuno Miguel Cabral; Abecasis, David Maria AguiarO tubarão azul, Prionace glauca, é uma espécie particularmente afetada pela atividade humana, não só devido à pesca de palangre, como também às alterações climáticas. Por um lado, os aumentos de temperatura provocam um afastamento de espécies marinhas dos trópicos, enquanto que a pesca de palangre contribui para o declínio populacional das espécies mais vulneráveis. O tubarão azul é uma das espécies mais abundantes e com distribuição mais abrangente dos elasmobrânquios pelágicos, e é também a espécie do grupo mais afetada pelo género de pesca referido anteriormente. Um dos fatores que contribui para este facto é a o facto da atividade pesqueira não ser regulada eficientemente no comércio do tubarão azul. Embora sejam realizados esforços para controlar a pesca não regulamentada, é praticamente impossível ter dados totalmente fidedignos quanto ao exato número de indivíduos pescados. Pelas razões supramencionadas, o impacto da pesca no tubarão azul permanece um assunto polémico. O presente estudo teve como objetivos aferir o efeito das alterações climáticas na distribuição do tubarão azul, bem como identificar as áreas nas quais os tubarões estão mais vulneráveis à pesca de palangre. No decorrer do projeto, recorrendo a dados de biotelemetria e a projeções futuras de condições climáticas, foram implementados modelos para avaliar o nível de adequação dos habitats em condições presentes e futuras, na região nordeste do Oceano Atlântico. Adicionalmente, os modelos de distribuição dos tubarões foram agrupados com os dados de monitorização da pesca, de modo a obter uma sobreposição geográfica. Num contexto de alterações climáticas, os modelos de distribuição futura do tubarão azul demonstraram cenários de redução de habitat e desvios de distribuição em algumas regiões, concordantes com os efeitos observados em outras espécies marinhas. Relativamente à vulnerabilidade à pesca, foram obtidas áreas extensas de sobreposição, tanto em cenários para o presente como para o futuro. É importante salientar que algumas zonas de elevada vulnerabilidade coincidiram com zonas de berçário, tais como a região dos Açores e a costa portuguesa. Para além das pressões atuais, é esperado que estas sobreposições se mantenham e, em certas regiões, expandam até ao fim do século, arriscando a sobre-exploração da espécie devido a uma exposição prolongada às pescas. Atendendo a este facto, foram sugeridas medidas protetoras adicionais, e.g., restrição de capturas por tamanho, de modo a evitar uma pesca insustentável da espécie. Em adição, uma melhor regulação e monitorização da pesca é crucial para obter melhores medidas de conservação do tubarão azul.
- Enhancing agriculture monitoring through anomaly detection of iot sensor dataPublication . Maia, André Miranda; Cardoso, Pedro Jorge Sequeira; Semião, Jorge Filipe Leal CostaEste trabalho propõe um aprimoramento no monitoramento agrícola por meio da detecção de anomalias utilizando dados de sensores IoT, aplicados especificamente em plantações de citros. O projeto investiga a integração de redes de sensores e técnicas de aprendizado de máquina para monitorar variáveis ambientais críticas, como evapotranspiração e a resistência interna do tronco das plantas. Ao incorporar dados meteorológicos da IPMA e de sensores instalados diretamente nas árvores, foi desenvolvido um sistema de monitoramento com o objetivo de detectar anomalias no uso da água e identificar reações anômalas das plantas em meio a condições ambientais adversas. Este sistema está atualmente em fase de coleta intensiva de dados, sendo que, no futuro, esses dados serão utilizados para retreinar os algoritmos de aprendizado de máquina, otimizando os processos de irrigação e minimizando o desperdício de recursos hídricos. Uma parte central do projeto foi a criação de um dashboard interativo, projetado para facilitar o acesso em tempo real às informações coletadas e processadas. Esse dashboard exibe dados ambientais e agrícolas, incluindo indicadores chave como evapotranspiração e consumo de água, fornecendo insights valiosos para os agricultores. O dashboard foi desenvolvido com tecnologias modernas de visualização de dados, permitindo personalização por localização geográfica e condições climáticas, e oferecendo uma plataforma prática para o gerenciamento de operações agrícolas em diversas regiões de Portugal. Os resultados preliminares indicam que o uso de algoritmos de detecção de anomalias é promissor para entender os padrões e as reações das árvores cítricas diante de mudanças climáticas, demonstrando potencial significativo para melhorar a eficiência no manejo da irrigação. Esse avanço pode representar uma contribuição importante para a sustentabilidade das operações agrícolas, reduzindo o desperdício de água e aumentando a resiliência das plantações em face das condições ambientais variáveis.
- Genetic parameters and genotype - environment interaction for growth and quality traits in whiteleg shrimp (Penaeus vannamei)Publication . Rüth, Timon Bijan; Gavaia, Paulo Jorge Travessa; Lopez, Juan Manuel AfonsoGenetic improvement of aquaculture species is crucial to ensure sustainable and profitable production. This applies especially to whiteleg shrimp (Penaeus vannamei), the most produced aquaculture species globally in terms of biomass. In this trial, conducted in the facilities of Grupo Almar, Ecuador, a population from a Penaeus vannamei breeding program (PMG-BIOGEMAR), comprised of full-sib and half-sib families, was assessed for heritability, genetic and phenotypic correlations and the genotype-environment interaction (GxE). The traits assessed in this study were related to weight, morphology, and quality (texture, and color). The company cultures its breeding nucleus in a high-salinity and high-density RAS environment, referred to as "ASIN", but conducts the commercial grow-out in low-salinity and low-density earth ponds, referred to as "BASIN". The vast differences between the two environments make it important to evaluate potential GxE effects between those two environments. Further, as the animals are commercialized and studied for genetic parameters in fresh, frozen, and thawed state, those three additional environments are equally of interest for GxE. For this particular trial, animals from the same families were cultured in “ASIN” and “BASIN” and traits of interest were studied in fresh, frozen and thawed state, depending on the trait and feasibility. Estimations for heritability of weight obtained in this study ranged from 0.22-0.34. For morphology traits, heritability was estimated from 0.05-0.32. Heritability estimates of quality traits ranged from 0.00-0.28 for texture traits, and 0.03-0.28 for color traits. Regarding the study of GxE, interactions were determined by genetic correlations between the same trait in the two respective environments. Considering growth traits between “ASIN” and “BASIN”, the estimations of genetic correlations ranged from 0.69 to 0.88, indicating low but notable interaction. Genetic correlation estimates for the same traits between fresh and thawed animals were high, ranging from 0.93 to 0.99, implying low to no GxE interaction. Genetic correlations between the color traits evaluated in frozen and thawed animals were high, ranging from 0.98 to 1. The standard errors were low, at 0.02-0.05, giving high confidence in the conclusion that no GxE is present.
- Genetic structure of the American elephantfish (Chimaeriformes: Callorhinchus callorynchus) in South AmericaPublication . Erk, Cornelia Pia; Veríssimo, Ana; Castilho, RitaUnderstanding genetic population structure and connectivity is key to the establishment of effective species-specific management and conservation strategies. The American elephantfish, Callorhinchus callorynchus, is a year-round target of commercial and recreational fisheries in Chile and Argentina. However, the scarcity of studies on chimaeroids´ population structure and connectivity hampers adequate fisheries management of this highly vulnerable group. In this work, we explore the levels of genetic diversity and differentiation within C. callorynchus in South America at two widely used mitochondrial markers, the control region (CR) and the cytochrome oxidase I gene (CO1). Moreover, we assess levels of genetic diversity within, and divergence among the three valid extant species of the genus Callorhinchus, which exhibit allopatric geographical distributions in the southern hemisphere. Overall, sequence analyses of the mitochondrial CR and the CO1 revealed extremely low levels of sequence variation both within and among Callorhinchus species. Genetic homogeneity was found throughout the range of C. callorynchus coupled to low-frequency haplotype sharing across spatially distant locations in Chile and Argentina, suggesting gene flow along the South American coast. Moreover, our analyses support a scenario of recent population expansion of the species in South America. Given the absence of dispersive eggs or juvenile stages in chondrichthyans, gene flow is mainly mediated by actively swimming adults. Based on the available data, gene flow in callorhinchids appears to occur along continuous coastal regions, with deep oceanic waters serving as strong barriers, thus providing an important baseline for future research on dispersal and gene flow in other holocephalans
- Improvement of senegalese sole sperm quality through the action of melatonin and other natural antioxidantsPublication . Melo, Francisca Félix de Azeredo Pinto e; Cabrita, Elsa; Oliveira, Catarina; Vera, LuisaNowadays, Senegalese sole industry still depends on wild-caught males to maintain reproduction in captivity, since F1 males do not spawn naturally and present low sperm volume and quality. This thesis intended to improve the sperm quality of F1 breeders using natural antioxidants, with a particular focus on melatonin, a night-hormone that controls reproduction and has a strong antioxidant capacity. First, through radioimmunoassay, it was reported for the first time that melatonin is present in fish seminal plasma, is species-specific and has day/night oscillations likewise in the bloodstream. Moreover, in Senegalese sole, it demonstrated to contribute to seminal antioxidant status, regardless of broodstock origin. The second objective was to find if gonads are an extra-pineal melatonin production site. Through real-time quantitative PCR, it was demonstrated that genes encoding for key enzymes involved in melatonin biosynthesis (tph1a, aanat1a, aanat2, hiomt1) and melatonin receptors (mel1 and mel2) were expressed in Senegalese sole brain, eye and testes, showing daily and seasonal variations, and different patterns according to fish origin. New information regarding the reproductive impairment of F1 males was given by the differences in seasonal blood melatonin levels and the lack of correlation between sex steroids in seminal plasma. The endogenous and exogenous effects of melatonin on sperm quality were also explored, and motility was enhanced by endogenous melatonin production. However, melatonin supplementation in the cryopreservation medium did not confer extra protection to spermatozoa. Nonetheless, promising results were obtained with other natural antioxidants supplemented in the broodstock diets: different algae-supplemented diets, with distinct bioactive compounds, modulated different spermatozoa traits according to the type of algae used and if used singly or combined. Overall, this thesis unravelled melatonin mechanisms in Senegalese sole reproductive system, found that industry could benefit from collecting sperm at night, and that algae-based antioxidants have the potential to improve sperm quality.
- Insights on meagre (Argyrosomus regius) spatial ecology around the Gironde estuary based on satellite telemetryPublication . Ribeiro, Inês Pires Moreira; Abecasis, David; Gandra, MiguelMeagre (Argyrosomus regius) is one of Europe's largest coastal fish and a top predator. It supports both commercial and recreational fisheries and has a growing importance in aquaculture. However, this long-lived species is particularly vulnerable due to significant genetic fragmentation and limited spawning areas. In these areas, they aggregate and are exposed to intense fishing pressures. Understanding the ecology and behavior of this species is crucial not only for fisheries management but also for conservation efforts. We used pop-up satellite archival tags (PSATs), to infer the movement and ecology of meagre, in one of its spawning areas, the Gironde estuary in France. 20 fish were tagged with PSAT, with 15 providing data over sampling periods ranging from 9 to 176 days, with an average of 72.2 days. The data was collected from June until December 2022. The remaining five tags did not transmit data due to a malfunction. The results show a seasonal shift in vertical habitat use where fish utilize shallower warmer waters during summer and deeper cooler waters during the winter, as observed in previous studies in Southern Portugal. Mean depth usage ranged from 5.66 (±1.98 SD) to 17.68 (±9.17 SD) meters, and temperatures ranged from 12.6°C to 24.95°C. The range of depths used in winter was wider than in summer. The opposite was found regarding temperature, with a wider range used during summer, when the water is stratified, and narrower during winter, as the water mixes. No patterns in diel vertical movement were detected. The geolocation models showed that between June and August, the meagre remained inside the estuary or nearby to coastal waters. Since September, meagre began dispersing to more offshore areas, though always inside the Bay of Biscay.
- Optimising sperm quality in flatfish through algae blend fish feed supplementationPublication . Parente, Pedro; Cabrita, Elsa; Oliveira, CatarinaFlatfish production is a growing sector in the Atlantic region, with turbot (Scophthalmus maximus) and Senegalese Sole (Solea senegalensis) being two important species with high market value in southern European countries. However, reproductive dysfunctions like the inability of captive bred individuals spawning spontaneously, poor sperm quality and quantity, still affect the obtention of progeny. Broodstock nutrition impacts reproductive performance, determining gonadal maturation, fecundity and larval survival. Sustainable supplements like micro and macroalgae, rich in essential compounds like vitamins and carotenoids are used in aquafeeds as they are known to enhance sperm quality and antioxidant defences. This study aimed to determine the effects of an algae blend supplementation on turbot and sole breeders’ diet, particularly on sperm quality. Two broodstocks of each species were fed either a control or an algae-supplemented diet for 3 months. For turbot, the algae diet was supplemented with 1% Laminaria digitata and 5% Arthrospira platensis, whereas sole’s diet was supplemented with 3% of Gracilaria birdiae and 3% of Phaeodactylum tricornutum. Sperm quality was evaluated through the analysis of motility, DNA fragmentation and lipid peroxidation (MDA). Total antioxidant status and the circulating levels of sex steroids were assessed in blood plasma samples. The algae diet improved sperm quality in turbot by decreasing DNA fragmentation and enhancing curvilinear and straight-line velocity. However, total motility and 11-ketotestosterone levels decreased, with an increase in malondialdehyde levels, indicating a possible shortening of the spawning cycle. In S. senegalensis the supplemented diet positively affected oxidative stress markers and showed normal oscillations of sperm kinetic parameters and DNA fragmentation. Nonetheless, testosterone levels decreased in the algae group, suggesting a shortening of the steroid cycle. Further studies should perform a deeper analysis by increasing the number of samplings, analyse antioxidant enzymes and algae’s specific compounds effects on each species.
- Study of parasite diversity and otolith shape of plaice (Pleuronectes platessa) off the coast of Iceland for stock discriminationPublication . Pubert, Eve-Marine; Randhawa, Haseeb; Erzini, KarimUnderstanding the stock structure of a commercial species is essential for sustainable management. Failure to do so can lead to the depletion of regional sub-populations, genetic diversity erosion, and ecosystem services loss. Plaice, Pleuronectes platessa, are a commercially important species for the Icelandic economy and are found in warm southern and cold northern waters. However, plaice is managed as a single stock. Over the last three decades, the use of parasites as biological markers has proved effective in distinguishing between different fish stocks. The use of otolith shapes for stock discrimination has gained popularity in recent years thanks to advances in image analysis tools and geometric methods. The study on 82 individuals of plaice from different geographical locations and seasons in Iceland showed that the community of parasites and the morphology of otoliths varied significantly between regions and periods, constituting several sub-populations in Icelandic waters. A notable differentiation between Icelandic plaice stocks was observed according to otolith shape and parasitic diversity. Otolith shape showed significant differences between the four geographical and seasonal groups (North-Summer, North-Winter, South-Summer, and South-Winter). Plaices collected in the southern region during the winter had otoliths with distinct shapes compared with the other groups. The parasite study confirmed the otolith shape results. The South-Winter group was also distinguished by a higher abundance of parasites and a different parasite composition than the other groups. Hysterothylacium aduncum was a candidate to be a parasite tag due to its constant presence throughout the year and in all regions but with notable variations in abundance and prevalence.
- Understanding host preference of Trioza erytreae (Del Guercio) by a multi-omics approachPublication . Magalhães, Tomás Thormann Abranches de; Marques, Natália Tomás; Duarte, Amílcar Manuel Marreiros; Pereira, José Alberto CardosoThe citriculture industry is significantly challenged by the devastating bacterial disease Huanglongbing (HLB). There is currently no eective cure for HLB, its management is based on inoculum elimination, and on the control of its vectors, namely the psyllids Trioza erytreae and Diaphorina citri. While Europe is currently free of HLB, T. erytreae is present in Spain and Portugal, two of Europe’s main citrus producers. The present study aimed to analyse the mechanisms underpinning T. erytreae's interaction with its citrus hosts. The plant hosts used in this study were the highly suitable lemon (Citrus ×limon) and the less suitable sweet orange (Citrus×sinensis). Both hosts were infested with T. erytreae adults, and three times more nymphs developed on lemon than on sweet orange plants. A multi-omics analysis on the plant’s enriched vascular sap of both citrus hosts revealed heightened primary and secondary metabolisms activity of sweet orange plants in response to infestation, including jasmonic acid (JA)-related defence mechanisms. A proteomic analysis of the nymphs revealed that the diet provided by lemon plants induced growth and energy pathways in T. erytreae. Based on these results, a subsequent experiment was conducted to stimulate the defence responses of lemon plants, analysing its eect on T. erytreae infestation and on the plants’ volatile organic compounds (VOC). Lemon plants were sprayed with JA to activate herbivory-related defences. The JA treatment resulted in a substantial reduction in the number of T. erytreae eggs and nymphs. Furthermore, the VOC profile was found to be aected by infestation and JA treatment, with high emission of (Z)-3-hexenol acetate, 2-hexen-1-ol and carveol. This research provides knowledge that can be used to develop novel methods for T. erytreae control, enhancing the array of responses to the HLB challenge and promoting a sustainable citriculture.