Natural recovery of the benthic nematode assemblages associated to Zostera noltii seagrass beds after physical disturbance caused by digging harvest activity

Seagrass beds are productive ecosystems that maintain high levels of biodiversity, making them susceptible to anthropogenic pressures such as bivalve harvesting. Nematodes are considered great ecological indicators as changes in their density, diversity and structure may represent changes in the environment. This experimental fieldwork aimed to assess the impact of the bivalve harvesting on the nematodes assemblage of a seagrass bed in the Mira estuary by simulating the digging activity. Two plots were subjected to the digging (D1 and D19) and two plots were control (C11 and C18). The sampling took place in five occasions: T0 – before digging; T1 – 14 days; T2 – 45 days; T3 – 75 days; and T4 – 165 days after digging. The results showed no significant difference in the nematode assemblages’ density, diversity and trophic composition between treatments and sampling times, evidencing their high tolerance for naturally stressed environments and to the level of digging they were exposed; Recuperação natural das comunidades de nematodes bentónicos associados aos povoamentos de Zostera noltii após atividade de marisqueio Resumo: As pradarias marinhas são ecossistemas produtivos que suportam elevados níveis de biodiversidade, pelo que estão sujeitos a pressões antropogénicas. Os nematodes são bons indicadores ecológicos pois respondem rapidamente a qualquer perturbação por alterações na densidade, diversidade e estrutura. Este trabalho experimental teve como finalidade o estudo da recuperação natural das comunidades de nematodes associados aos povoamentos de Zostera noltii pela simulação da atividade de marisqueio. Dois plots foram sujeitos a revolvimento (D1 e D19) e dois plots serviram como controlo (C11 e C18) e foram efetuadas amostragens em cinco ocasiões: T0 – antes do revolvimento; T1 – 14 dias; T2 – 45 dias; T3 – 75 dias; e T4 – 165 dias após revolvimento. Os resultados obtidos não mostraram diferenças significativas na diversidade, densidade e composição trófica das comunidades de nematodes entre tratamentos e tempos de amostragem, evidenciando a sua elevada tolerância a ambientes naturalmente dinâmicos e ao nível de revolvimento a que foram expostas.

Bivalves marinhos do miocénio superior (Tortoniano superior) de Cacela (Algarve, Portugal)

Dissertação de mestrado em Estudos Marinhos e Costeiros, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve, 2000

Tafonomia e paleoicnologia do neogénico superior do sector Cacela-Huelva (SE da Ibéria)

Tese de doutoramento em Paleontologia. Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2005

Bioaccumulation and effects of TBT on molluscs from southern Portugal

Tese de dout. Ciências e Tecnologias do Ambiente, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2004

Multibiomarker assessment of cadmium-based quantum dots effects in the marine mussel Mytilus galloprovincialis

Tese de Doutoramento, Ciências do Mar, da Terra e do Ambiente, Ramo: Ciências e Tecnologias do Ambiente, Especialização em Ecotoxicologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Highly polymorphic microsatellite markers for the Mediterranean endemic fan mussel Pinna nobilis

Pinna nobilis is an endemic bivalve of the Mediterranean Sea whose populations have decreased in the last decades due to human pressure; as a consequence, it was declared a protected species in 1992. Despite its conservation status, few genetic studies using mitochondrial markers have been published. We report on the isolation and development of 10 microsatellite loci for the fan mussel, Pinna nobilis. All loci (2 di-nucleotide, 5 tri-nucleotide, 2 tetra-nucleotide and 1 penta-nucleotide) are characterized by high levels of polymorphism in 76 individuals tested from two populations in the Balearic Islands (Spain, Western Mediterranean Sea). The number of alleles ranged from 4 to 24 and expected heterozygosity ranged from 0.4269 to 0.9400. These microsatellites could be very useful for the assessment of the genetic diversity and connectivity patterns of P. nobilis and the establishment of new conservation strategies.

Molluscan diversity caught by trawling fisheries: a case study in southern Portugal

The effects of commercial trawling on the malacological communities (except for the Cephalopoda) were examined, based on a study undertaken between 1996 and 2000 on the continental shelf and slope of southern Portugal. More than 50% of species caught by trawling in southern Portugal were discarded, with molluscs representing about 19%. Forty-four species of molluscs (15 bivalves, 28 gastropods and one polyplacophoran) were identified from the discarded specimens. Crustacean trawlers accounted for 34 molluscs species, and fish trawlers for 24. Twenty species were only caught by the crustacean trawl, compared with 10 species by the fish trawl, and 14 species were common to both trawls. The bivalve Venus nux Gmelin was the most numerous species discarded in the fish trawl, accounting for 42.0% of the total number of individuals, followed by the gastropods Ampulla priamus (Meuschen) (7.8%) and Ranella olearium (L.) (7.3%). In the crustacean trawl, the most numerous species discarded were the bivalve Anadara diluvii (Lamarck) (19.4%), the gastropod Calliostoma granulatum (Born) (15.5%), and the bivalve V. nux (15.1%). The third most discarded species from fish trawls in Algarve waters, the gastropod species R. olearium, is a species listed in Annex II of the Bern Convention. The difficulties of managing the real impact of fisheries on the molluscan populations and in defining a conservation strategy are discussed.

Enzymatic activity on sediments and nematode assemblage responses during seagrass beds habitat recovery following the disturbance of the traditional digging activity of bivalves harvesting.

Sediment digging is an anthropogenic activity connected to the exploitation of living resources in estuarine and marine environments. The knowledge on the functional responses of the benthic assemblages to the physical disturbance is an important baseline to understand the ecological processes of the habitat recovery and restoration and to develop tools for the management of the harvesting activities. To investigate the effects of the digging activity of the bivalves on Zostera noltii seagrass beds a manipulative field experiment was conducted that included the enzymatic activity of sediments and the associated nematode assemblages. Four plots (two undisturbed serving as control and two dug to collect bivalves - treatment) with 18 subplots were randomly located at seagrass beds in the Mira estuary at the SW coast of Portugal. Samples were randomly and unrepeatably collected from three subplots of each plot in five different occasions, before sediment digging (T0) up to six months after disturbance (T5). Microbial activity in sediments was assess by determining the extracelular enzymatic activity of six hydrolytic enzymes (sulfatase, phosphatase, b -N-acetilglucosaminidase, b-glucosidase, urease, protease) and two oxidoreductases (phenol oxidase and peroxidase). The microbial community status was also assessed through the measurement of dehydrogenase, which reflects microbial respiration. The nematode assemblages composition, biodiversity and trophic composition at different sampling occasions were also analyzed. The fluorometric and biochemical parameters analysed of the Z. noltii plants during the experimental period showed a recovery of the seagrass beds, and it was detected an increase of the enzymatic activity of the sediments after disturbance. The nematodes assemblages were similar in all sampling occasions. The seagrass beds and the nematodes assemblages associated showed a high resilience to the stress caused by the traditional bivalves digging activity. The obtained results allow the development of a management programme for the commercial fishing activity to maintain the good environmental status and minimized the secondary environmental effects on marine and estuarine habitats through the establishment of a baseline for the regulation of the harvesting frequency.

Sistemas de produção de peixes e bivalves em aquacultura: crescimento e indicadores de qualidade

O presente relatório refere-se ao estágio curricular realizado na Estação Piloto de Piscicultura de Olhão, no período compreendido entre janeiro e julho de 2016, no âmbito do Mestrado Integrado em Medicina Veterinária da Universidade de Évora. Este trabalho divide-se em duas partes. A primeira parte descreve as atividades e respetiva casuística desenvolvidas nas diferentes áreas de produção aquícola. Na segunda parte é abordado o tema “Produção Aquícola de Peixes e Ostras em regime Semi-intensivo”, onde são enquadrados os conceitos relacionados com aquacultura, sistemas de produção e pesquisa de biomarcadores na qualidade e bem-estar animal. São ainda descritas as ações de acompanhamento, durante o estágio, de um projeto de investigação em sistemas de produção em tanques de terra exteriores e um caso clínico. Este relatório atesta a importância da Medicina Preventiva em aquacultura; Abstract: Fish and bivalve aquaculture production systems: growth and quality indicators The following report was elaborated after the externship conducted at the Olhão Pilot Aquaculture Station, between January and July of 2016, in order to fulfill the requirements for a Masters degree in Veterinary Medicine at the University of Évora. This report is divided in two parts. The first part contains a description of the developed activities and the casuistic at the different aquaculture production areas. The second part will focus on the development of the theme “Fish and Oyster aquaculture production in a semi-intensive culture system”, with a theoretical framework about aquaculture concepts, production systems and identifying biomarkers in animal healthcare. At last, are presented and supported the monitoring actions taken in an investigation study case about inshore production systems and a clinic case followed during the externship. This report attests the importance of Preventive Medicine in aquaculture.