Browsing by Author "Prestes, Afonso L."
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- Aquaculture of the clam (Tapes decussatus) on a closed system.Publication . Pereira, Nuno M.; Rebelo, Ana C.; Lourenço, Tânia M.; Amaral, André; Prestes, Afonso L.; Azevedo, José M. N.; Neto, Ana I.
- Avaliação do stock de Abalones: uma pesca sustentávelPublication . Prestes, Afonso L.; Neto, Ana I.; Rodrigues, Armindo; Martins, Gustavo M.A falta de informação anterior ao início de uma exploração de uma espécie alvo é ponto comum à maior parte das pescarias. A maioria dos estudos só é iniciada após indícios claros de efeitos de um excesso de pesca. No entanto, esta situação é indicadora de que a pesca já causou alterações drásticas na estrutura das populações alvo e que, consequentemente, já não existe um ponto de referência que informe a gestão e a recuperação dos mananciais. A exploração do abalone nos Açores é virtualmente inexistente, ao contrário de muitas outras regiões onde a sua captura tem levado à ruptura dos mananciais. A espécie existente nos Açores, Haliotis tuberculata, é um recurso com elevado interesse gastronómico e económico e existem indícios de que tem sido gradualmente introduzida na gastronomia regional. Nos Açores os mananciais de H. tuberculata podem, à partida, ser considerados virgens, mas não existe informação sobre a sua abundância, biologia e ecologia. Concomitantemente, não existe qualquer tipo de restrição ou legislação regional relativamente à exploração deste marisco. O presente projecto tem como objectivo avaliar o estado actual das populações de H. tuberculata providenciando um ponto de referência para estudos futuros e garantindo deste modo uma avaliação rigorosa dos impactos de uma potencial pescaria. Neste projecto examinam-se aspectos da biologia e da ecologia de H. tuberculata que providenciarão dados úteis para garantir uma exploração sustentável deste recurso. O presente estudo providenciará também recomendações para a gestão desta pescaria baseadas na revisão bibliográfica e na informação recolhida.
- The Azorean edible abalone Haliotis tuberculata, an alternative heavy metal-free marine resource?Publication . Torres, Paulo; Rodrigues, Armindo; Prestes, Afonso L.; Neto, Ana I.; Álvaro, Nuno V.; Martins, Gustavo M.Abalones are considered a delicacy and exploited for food worldwide. In many places, overfishing has led to the decimation of wild stocks and many are now reared in aquaculture systems. In the Azores, there is no tradition of eating abalones and Haliotis tuberculata stocks are still virtually untouched. However, as tourism in the islands grows and the stocks of other shellfish diminish, there is an increasing pressure to find alternative edible resources, leading to a rising interest in abalones. According to previous studies performed in the region, other edible species, including the local highly appreciated limpets and the giant barnacle, present high concentration levels of some heavy metals, which has been attributed to the volcanic origin of the islands. Here we analysed the metal content in the edible tissue of Haliotis tuberculata from São Miguel Island, Azores. The potential human health risks due to its consumption was assessed by estimating the average daily intake (EDI) and target hazard quotient (THQ) of metals. Similarly to other organisms in the Azores, abalones have higher than normal levels of some heavy metals, particularly cadmium, reflecting a local natural source that should be closely monitored from a public health point of view.
- Can islets be considered repositories of neighbouring coastal biodiversity?Publication . Moniz, Isadora; Prestes, Afonso L.; Nogueira, Eunice M.; Azevedo, José M. N.; Álvaro, Nuno V.; Neto, Ana I.
- Characterization of transitional waters in the Azorean archipelago.Publication . Prestes, Afonso L.; Patarra, Rita F.; Álvaro, Nuno V.; Terra, Marlene R.; Fontaine, Camile; Cámara, Albert; Azevedo, José M. N.; Neto, Ana I.
- Coastal water characterization in the Azorean archipelago.Publication . Patarra, Rita F.; Prestes, Afonso L.; Álvaro, Nuno V.; Terra, Marlene R.; Fontaine, Camile; Cámara, Albert; Azevedo, José M. N.; Neto, Ana I.
- Differences in the structure and functioning of two communities : frondose and turf-forming macroalgal dominated habitatsPublication . Martins, Gustavo M.; Hipólito, Cláudia; Parreira, Filipe; Prestes, Afonso L.; Dionísio, Maria Ana; Azevedo, José M. N.; Neto, Ana I.In many coastal regions, vegetated habitats (e.g. kelps forests, seagrass beds) play a key role in the structure and functioning of shallow subtidal reef ecosystems, by modifying local environmental conditions and by providing food and habitat for a wide range of organisms. In some regions of the world, however, such idiosyncratic ecosystems are largely absent and are often replaced by less notable ecosystem formers. In the present study, we empirically compared the structure and functioning of two distinct shallow-water habitats present in the Azores: one dominated by smaller frondose brown macroalgae (Dictyotaceae and Halopteris) and one dominated by low-lying turfs. Two replicated areas of each habitat were sampled at two different times of the year, to assess spatial and temporal consistency of results. Habitats dominated by small fronds were significantly (ca. 3 times) more productive (when standardized per algal mass) compared to the turf-dominated habitats, and supported a distinct assemblage (both in terms of composition and abundance) of associated macrofauna. Unlike other well-known and studied vegetated habitats (i.e. kelp forests), however, no effects of habitat were found on the structure of benthonic fish assemblages. Results were spatially and temporally consistent suggesting that, in warmer temperate oceans, habitats dominated by species of smaller frondose brown algae can also play an important role in the structure and functioning of subtidal communities and may, to a certain extent, be considered analogous to other well-known vegetated habitats around the world (i.e. kelp forests, seagrass beds).
- Dramatic changes in the structure of shallow-water marine benthic communities following the invasion by Rugulopteryx okamurae (Dictyotales, Ochrophyta) in Azores (NE Atlantic)Publication . Faria, João; Prestes, Afonso L.; Moreu, Ignacio; Cacabelos, Eva; Martins, Gustavo M.Biological invasions are considered one of the most important drivers of biodiversity loss. Here we use a before-after-control-impact (BACI) design to investigate the impact of Rugulopteryx okamurae on the structure of shallow-water marine benthic communities in São Miguel island, Azores. After its first appearance in 2019, R. okamurae has rapidly invaded much of the southern coast of the island, where it became the dominant algae. This was followed by significant changes in the structure of shallow-water marine benthic communities, with substantial losses of natural variability and species richness. Compared to before, there has been dramatic reductions in the abundances of articulated coralline algae, corticated algae and corticated foliose algae in invaded locations. These results highlight its highly invasive character, not seen with other, more well-known, invasive species. It remains to be investigated if its impacts persist throughout time and to quantify the functional consequences of such dramatic changes.
- Ecological quality of Azorean coastal waters.Publication . Neto, Ana I.; Patarra, Rita F.; Brotas, Vanda; Álvaro, Nuno V.; Gameiro, Carla; Silva, Alexandra A.; Diniz, Tania; Prestes, Afonso L.; Azevededo, José M. N.; Medeiros, Margarida C.; Pacheco, Dina M.; Gaspar, João L.
- Ecological quality of Azorean coastal waters: macrophytes and phytoplankton evaluation.Publication . Patarra, Rita F.; Brotas, Vanda; Álvaro, Nuno V.; Gameiro, Carla; Silva, Alexandra A.; Diniz, Tania; Prestes, Afonso L.; Azevedo, José M. N.; Medeiros, Margarida C.; Pacheco, Dina M.; Gaspar, João L.; Neto, Ana I.