35,955 research outputs found

    O valor ecológico dos predadores de topo e o estudo do caso do tubarão azul

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    Top predators have an important role in the trophic chain, especially in marine ecosystems, where the hypothesis that pristine biomass pyramids are inverted and therefore, with a more pronounced top-down control, is highly debated. Their abundance, however, have showed a marked decline over the years, due to exploitation and human-predator conflicts. Currently, a better appreciation of the importance of the relationships between species, have pushed areas like fishery research, to look at ecosystem-based management, with multispecies management strategies. Sharks are notorious predators, highly vulnerable to the many threats they face, due to their biological characteristics. Particularly, blue shark (Prionace glauca), because of its wide distribution is one of the shark species most impacted by fisheries. Here, the objective is to understand what can be inferred about the state of the blue shark population using records of landings in Portuguese ports, since 1989. The analysis focused on data of landings, average price, and size. Results showed a tendency for decreasing landings and increasing average price over time, which can be associated with overfishing. Size data was very inconstant and not very informative, it did not seem as relevant for juvenile protection as it could and should be. General measures for blue shark protection have been implemented since 2016, but more attention should be given to the large number of juveniles that inhabit the Exclusive Economic Zone (EEZ) of Portugal. Further studies could focus on the ecological value of this species for the ecosystem and, particularly in Portugal, on a better understanding of the market and of consumer knowledge and awareness.Os predadores de topo t√™m um papel fundamental nas cadeias tr√≥ficas, principalmente nos ecossistemas marinhos, onde a hip√≥tese de que, as pir√Ęmides de biomassa de habitats pristinos s√£o invertidas e, consequentemente com um controlo top-down mais acentuado, √© bastante debatida. A abund√Ęncia destes predadores, no entanto, tem vindo a diminuir ao longo dos anos, devido √† sua explora√ß√£o e a conflitos entre o ser humano e predadores. Atualmente, o reconhecimento da import√Ęncia das rela√ß√Ķes interespec√≠ficas, motivou a √°rea da investiga√ß√£o pesqueira a considerar uma gest√£o baseada nos ecossistemas, com estrat√©gias que contemplem as multiesp√©cies envolvidas. Os tubar√Ķes s√£o predadores not√≥rios, altamente vulner√°veis √†s v√°rias amea√ßas que enfrentam devido √† sua biologia caracter√≠stica. Particularmente, o tubar√£o azul (Prionace glauca), devido √† sua larga distribui√ß√£o, √© uma das esp√©cies mais afetadas pela atividade pesqueira. O objetivo deste trabalho √© compreender o que pode ser inferido sobre o estado da popula√ß√£o de tubar√£o azul, usando os registos de desembarques em portos Portugueses, desde 1989. A an√°lise focou-se na quantidade de tubar√£o azul desembarcada, no pre√ßo m√©dio e no tamanho dos indiv√≠duos desembarcados. A quantidade desembarcada apresentou uma tend√™ncia para diminuir ao longo dos anos, enquanto que o pre√ßo m√©dio, uma tend√™ncia para aumentar, o que pode ser um indicador de risco de sobrepesca. O registo do tamanho dos indiv√≠duos revelou-se extremamente inconstante, e pouco esclarecedor em rela√ß√£o √† pesca de juvenis, sendo que esta informa√ß√£o pode ser importante para a sua prote√ß√£o. V√°rias medidas t√™m vindo a ser implementadas para proteger esta esp√©cie desde 2016, no entanto, mais aten√ß√£o deveria ser dada √† quantidade de juvenis que habita a Zona Econ√≥mica Exclusiva (ZEE) de Portugal. No futuro, uma melhor compreens√£o do valor ecol√≥gico desta esp√©cie e, particularmente em Portugal, do seu mercado e do conhecimento do consumidor, podem ser factores importantes para a sua conserva√ß√£o.Mestrado em Ecologia Aplicad

    ‚ÄėBetween the land and the sea‚Äô: a visual etnography of the sargassum harvest in the fishing community of Angeiras, Matosinhos

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    Disserta√ß√£o de mestrado em Patrim√≥nio CulturalA apanha do sarga√ßo constitui uma atividade imemorial, complementar √† atividade agr√≠cola, que pressup√Ķe a recolha e secagem das macroalgas para fertiliza√ß√£o das colheitas. Antes da aplica√ß√£o generalizada dos adubos qu√≠micos, as popula√ß√Ķes rurais dedicavam-se tamb√©m a esta faina agromar√≠tima, considerada uma das formas mais eficazes de fertiliza√ß√£o da terra. O incremento da procura deste recurso natural para fins agr√≠colas deu origem a um fluxo populacional crescente em seu torno e a uma aproxima√ß√£o gradual das gentes para junto da linha da costa. Enquanto elemento de liga√ß√£o entre o espa√ßo terrestre e mar√≠timo, a recolha de sarga√ßo contribuiu significativamente para a forma√ß√£o e fixa√ß√£o de aglomerados costeiros no litoral Norte portugu√™s ao longo dos s√©culos, visto que apesar das suas motiva√ß√Ķes agr√≠colas, a atividade acabou por se desenvolver, econ√≥mica e socialmente, em estreita rela√ß√£o com a atividade piscat√≥ria. Neste sentido, a presente investiga√ß√£o tem como objeto central de estudo as din√Ęmicas culturais em torno da atividade sargaceira na comunidade piscat√≥ria de Angeiras, pertencente √† freguesia de Lavra, no munic√≠pio de Matosinhos. A instabilidade financeira e a falta de condi√ß√Ķes de vida e trabalho na regi√£o contribu√≠ram para a forma√ß√£o gradual de aglomerados costeiros, cuja consolida√ß√£o dependeu, significativamente, da explora√ß√£o dos recursos hali√™uticos. A diversidade de perfis sociol√≥gicos que est√£o na sua origem contribu√≠ram para a forma√ß√£o de uma comunidade sociologicamente h√≠brida, cuja identidade √© indissoci√°vel das rela√ß√Ķes estabelecidas entre a terra e o mar. Assim, com recurso a uma metodologia etnogr√°fica e visual de an√°lise, a presente investiga√ß√£o visa refletir acerca do processo de constru√ß√£o identit√°ria da comunidade piscat√≥ria de Angeiras e do papel da pr√°tica sargaceira na dupla natureza agr√≠cola e mar√≠tima das suas gentes. Detentores de um patrim√≥nio cultural material e imaterial not√°vel, torna-se essencial compreender o seu passado t√©cnico, social e econ√≥mico de modo a tentar descodificar um modo de vida partilhado cujos h√°bitos, objetos, comportamentos, pol√≠ticas de g√©nero, saberes e tradi√ß√Ķes contribuem, conjuntamente, para dar conta de processos espec√≠ficos de apropria√ß√£o pr√°tica e simb√≥lica do ‚Äúespa√ßo‚ÄĚ onde a comunidade interage e se desenvolve. Para al√©m disso, na tentativa de contrariar o atual cen√°rio de desperd√≠cio e inutiliza√ß√£o do sarga√ßo que abrange a costa portuguesa, exploram-se solu√ß√Ķes alternativas e inovadoras para o seu destino, atendendo ao potencial de aplica√ß√£o das macroalgas numa s√©rie de produtos e ind√ļstrias.The sargassum harvest is an immemorial activity, complementary to agricultural activity, which involves collecting and drying macroalgae to fertilise the soil. Before the widespread application of chemical fertilisers, rural populations also engaged in this agromaritime activity, considered one of the most effective ways to fertilise the soil. The increased demand for this natural resource for agricultural purposes led to a growing population flow around it and to people gradually moving closer to the coastline. Being a connection between the land and sea, sargassum harvest contributed significantly to the formation of coastal settlements on the northern coast of Portugal over the centuries, because, despite its agricultural motivations, the activity ended up developing, economically and socially, in close relationship with fishing activity. In this sense, the present research has as its central subject of study the cultural dynamics around the sargassum harvest in the fishing community of Angeiras, part of village of Lavra, in Matosinhos. The financial instability and the lack of living and working conditions in this region contributed to the gradual formation of coastal settlements, whose consolidation depended, significantly, on the exploitation of fishery resources. The diversity of sociological profiles at its origin contributed to the formation of a sociologically hybrid community, whose identity is linked to the relationships established between land and sea. Thus, using an ethnographic and visual analysis methodology, this research aims to reflect on the process of identity construction of the fishing community of Angeiras and the role of the sargassum harvest in the simultaneously agricultural and maritime nature of its people. Detainers of a remarkable material and immaterial cultural heritage, it becomes essential to understand its technical, social and economic past in order to try to decode a shared way of life whose habits, objects, behaviours, gender politics, knowledge and traditions, which represent specific processes of practical and symbolic appropriation of the "space" where the community interacts and develops. Furthermore, in the attempt to prevent the current scenario of waste and unusability of the sargassum on the portuguese coast, alternatives and innovative solutions are explored for sargassum‚Äôs utility, analising potential application of macroalgae in several products and industries

    Building Angola: A Political Economy of Infrastructure Contractors in Post-War Angola

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    Following the end of the civil war in 2002, Angola entered a period of political stability and economic growth that was sustained until the oil-price crisis hit the economy in 2015. During this period a vast reconstruction plan of economic infrastructure was implemented. This process induced a series of changes that shaped the construction industry in the country, especially the rise of Angolan contractors as a by-product of the primarily externally funded reconstruction effort. This article aims to understand the political economy of infrastructure building in Angola‚Äôs post-war reconstruction boom and the post-2015 crisis. We focus on the nature and dynamics of the emerging infrastructure market segmentation that led to the coexistence of Angolan, Chinese and other foreign contractors, when a part of oil rents was reinvested in infrastructure development, thereby generating a rapid development of the construction sector and its ancillary economic activities. The article explains the origins of segmentation among infrastructure contractors and the central role of oil-backed finance, particularly from China, during the boom and the crisis. It demonstrates the political imperatives of fast delivery of infrastructure assets for the maintenance of the dominant political settlement and the distribution of organisational power in Angola, which led to the rise of a well-organised element of state-linked Angolan capital in this lucrative sector. These experiences reflect the centrality of market segmentation and state‚Äďbusiness relations in the evolution of the infrastructure sector in Angola, and the implications for the rise and consolidation of domestic capitalist interests

    Impact of polyester and cotton microfibers on growth and sublethal biomarkers in juvenile mussels

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    Anthropogenic microfibres are a prevalent, persistent and globally distributed form of marine debris. Evidence of microfibre ingestion has been demonstrated in a range of organisms, including Mytilus spp. (mussels), but the extent of any impacts on these organisms are poorly understood. This study investigates, for the first time, the effect of exposing juvenile mussels to polyester and cotton microfibres at environmentally relevant concentrations (both current and predicted future scenarios) over a chronic timescale (94 days). Sublethal biomarkers included growth rate, respiration rate and clearance rate. Mussels were exposed to polyester (median length 149 ¬Ķm) and cotton (median length 132 ¬Ķm) microfibres in three treatments: polyester (~‚ÄČ8 fibres L‚ąí1), polyester (~‚ÄČ80 fibres L‚ąí1) and cotton (~‚ÄČ80 fibres L‚ąí1). Mussels exposed to 80 polyester or cotton microfibres L‚ąí1 exhibited a decrease in growth rate of 35.6% (polyester) and 18.7% (cotton), with mussels exposed to‚ÄČ~‚ÄČ80 polyester microfibres L‚ąí1 having a significantly lower growth rate than the control population (P‚ÄČ<‚ÄČ0.05). This study demonstrates that polyester microfibres have the potential to adversely impact upon mussel growth rates in realistic future scenarios, which may have compounding effects throughout the marine ecosystem and implications for commercial viability

    Key Determinants of Job Satisfaction Among University Lecturers

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    Creating job satisfaction for employees can help organizations maintain their employees and save more costs from searching for new ones. Therefore, a primary goal of this research was to investigate how work-family conflict, workload and job stress influenced university lecturers’ work satisfaction. To accomplish the current aim, researchers invited 450 respondents who were currently having positions as lecturers at any university in Thailand. Next, a structural equation model was employed to analyze 387 valid data. In gender statistics, 45.2% were male respondents, while 54.8 % were female. Moreover, gender obtained mean scores of 1.54 with standard deviation scores of 0.49. Based on age statistics, most of the respondents who joined this research were between 20-30 years (41.3%), followed by 31-41 years (24.5%), 41-50 years (19.9%) and above 50 years (14.2%). Meanwhile, its mean score (is 2.07 with a standard deviation of 1.09. According to the results of this research, increasing work-family conflict and workload caused lecturers to receive more stress from their work. Moreover, the lecturers were happy once certain degrees of stress and work-family conflict, except workload, diminished. Meanwhile, stress among university lecturers significantly mediated their workloads and work satisfaction. This result highlighted a side effect of a certain number of workloads influencing lecturers’ stress levels, which increased the significant role of job stress in further influencing lecturers’ work satisfaction

    Diagnostic Survey of Honeybee Diseases, Pests and Predators in Bale Zone Southeast Oromia Region, Ethiopia

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    A cross-sectional study was conducted on parasitic honeybee diseases, pests and predators in Bale. For the study questionnaires and diagnostic survey were employed.  A sample of adult worker bees and brood for major honeybee diseases were taken and analyzed in veterinary laboratory of respective districts of the study. SPSS version 20 was used for data analysis using descriptive statistics (frequency, percentage and chi-square. From the present study, the major challenge declared by beekeepers includes pests and predators, lack of bee forage, absconding and mass death of bee colonies. Regarding to honeybee pests and predators, the most important identified were honey badger, spiders ant, wax moth, bee-eater birds, small hive beetles and monkeys. The study indicated the overall mean prevalence of Nosema apis, Amoeba mellifera, Varro mites,  bee lice, wax moth, small hives beetles  were 79.17 %, 79.16%, 72.22%, 18.06%, 40.27% and 54.2 % respectively. However, the current diagnosis was not detected AFB, EFB, and trachea mites during laboratory sample analysis. Agro ecology and hive types were identified as risk factors for prevalence of honeybee diseases and pests.  Further study on prevalence of seasonal honeybee diseases and outbreak of honeybee diseases and pests is could be very important. Keywords: Honeybee, Nosema apis, Malpighamoeba mellificae, diagnostic, disease, pests DOI: 10.7176/JBAH/13-6-01 Publication date: April 30th 202

    DataSheet_1_Three trap designs evaluated for a deepwater lionfish fishery.zip

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    A deepwater (>40¬†m) fishery for invasive lionfish (Pterois volitans/miles) offers a potential means to control invasive lionfish densities and mitigate their impacts on reefs too deep for SCUBA removals. Trapping could provide a scalable solution‚ÄĒif an effective fishing gear with minimal environmental impacts could be permitted and adopted by fishers. We tested the efficacy of wooden slat lobster traps, wire sea bass traps, and experimental non-containment Gittings traps. One hundred deployments of each trap type were made at 120 mesophotic (38‚Äď78 m deep) natural reef sites in the northeastern Gulf of Mexico (29.6‚Äď30.1¬įN, 86.1‚Äď87.6¬įW). Reef sites were surveyed with remotely operated vehicles (ROV) before and after trap deployments, and remote time-lapse video cameras were affixed above 86 traps to sample in situ recruitment to the traps. The video data showed that lionfish were attracted to the vicinity of the three trap types at similar rates, but that lionfish rarely entered the lobster or sea bass traps. The high bycatch rates of sea bass traps suggested their use is likely unsuitable for targeting lionfish. Lobster traps had lower rates of bycatch, but their relatively high ratio of bycatch-to-lionfish catches suggests that modifications will be needed to make them more efficient. The Gittings traps had the highest lionfish catch rates and lowest bycatches of native fishes, but operational issues were also identified. They failed to open on 20% of deployments and one entangled a green sea turtle (Chelonia mydas). Even with the best-performing trap design, the average catch rate of lionfish was less than one lionfish per trap. A potential explanation could be the low biomass of lionfish observed during the ROV surveys, which averaged 0.3¬†kg lionfish per site. The time-lapse video data suggested that lionfish recruitment to Gittings traps could increase with higher densities of lionfish on the nearby reefs, if traps were retrieved after approximately two days of deployment, and if traps were retrieved during dawn or dusk. Further research, development, and testing is needed for lionfish traps, and critical bio- and techno-economic assessments appear warranted to evaluate the feasibility of a deepwater lionfish fishery.</p

    Genetic population structure of the precious coral Corallium japonicum in the Northwest Pacific

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    Population sizes of the Japanese red coral Corallium japonicum have been severely affected by poaching and overfishing. Although genetic structure and connectivity patterns are considered important parameters for conservation strategies, there are few studies focusing on the population genetics of C. japonicum in the Northwest Pacific. We examined the genetic population structure of C. japonicum, in the Northwest Pacific. We used restriction-site-associated DNA sequencing (RAD-seq), which can be used to identify genome-wide single-nucleotide polymorphism (SNPs), to reveal detailed within-species genetic variations. Using the variable SNP loci identified from this analysis, we successfully evaluated the population-level genetic diversity and patterns of gene flow among multiple populations of C. japonicum around Japan. The results of genetic analysis basically showed that gene flow is widely maintained in the geographic range examined in this study, but the analysis in combination with larval dispersal simulations revealed several populations that were genetically distinct from the other populations, suggesting geographically limited gene flows. The information obtained from this study will be useful for the design of effective management schemes for C. japonicum, which is under threat from overfishing

    Valoración de dos métodos para identificación molecular (PCR - RFLP y qPCR) de Babesia bigemina en bovinos de zonas endémicas para babesiosis

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    La babesiosis bovina es una enfermedad causada por par√°sitos protozoarios intraeritroc√≠ticos del g√©nero Babesia, distribuidos en √°reas tropicales y subtropicales del mundo, que ocasionan enfermedades an√©micas en los animales y son transmitidas por las garrapatas. Ecuador tiene un clima tropical que permite el desarrollo del vector Rhipicephalus microplus, por tanto, favorece la transmisi√≥n de Babesia spp en ganado. Los factores clim√°ticos, as√≠ como la movilidad de los animales portadores de garrapatas sin ning√ļn tipo de control permiten la presencia de brotes en nuevas √°reas geogr√°ficas. Las infecciones por babesiosis son dif√≠ciles de detectar debido al bajo n√ļmero de par√°sitos en sangre perif√©rica. Por lo tanto, se han empleado m√©todos moleculares basados en el ADN para el diagn√≥stico debido a su alta sensibilidad y especificidad, siendo esta t√©cnica la PCR. El presente estudio se realiz√≥ en el cant√≥n Gir√≥n perteneciente a la provincia del Azuay donde se tomaron un total de 100 muestras de sangre de bovinos, ubicados en zonas end√©micas para babesiosis, en el cual se identific√≥ la presencia de material gen√©tico de B. bigemina mediante dos t√©cnicas de biolog√≠a molecular. Los resultados obtenidos mostraron el 43% de muestras positivas en el ensayo qPCR y para PCR-RFLP el 11%, en el an√°lisis estad√≠stico aplicado se determin√≥ que si hay significancia estad√≠stica entre los dos ensayos; lo que sugiere que la efectividad del m√©todo molecular convencional PCR-RFLP es menor frente a qPCR al momento de detectar ADN de Babesia bigemina.Bovine babesiosis is a disease caused by intraerythrocytic protozoan parasites of the genus Babesia, distributed in tropical and subtropical areas of the world, which cause anemic diseases in animals and are transmitted by ticks. Ecuador has a tropical climate that allows the development of the vector Rhipicephalus microplus, and therefore favors the transmission of Babesia spp in cattle. Climatic factors, as well as the mobility of tick-carrying animals without any type of control, allow the presence of outbreaks in new geographical areas. Babesiosis infections are difficult to detect due to the low number of parasites in peripheral blood. Therefore, DNA-based molecular methods have been used for diagnosis due to their high sensitivity and specificity, this technique being PCR. The present study was carried out in the Gir√≥n canton belonging to the province of Azuay where a total of 100 blood samples were taken from cattle, located in endemic areas for babesiosis, in which the presence of genetic material of B. bigemina was identified by means of two molecular biology techniques. The results obtained showed 43% of positive samples in the qPCR assay and 11% for PCR-RFLP, in the statistical analysis applied it was determined that there is statistical significance between the two assays, suggesting that the effectiveness of the conventional molecular method PCR RFLP is lower compared to qPCR when detecting Babesia bigemina DNA.M√©dico Veterinario ZootecnistaCuenc
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