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- Anelídeos poliquetas como isco vivo: caracterização da atividade de apanha em ambientes salobros costeiros PortuguesesPublication . Fidalgo E Costa, Pedro; Sá, Erica; Alves, Ana Sofia; Cabral, Sara; Castro, Nuno; Picard, David; Castro, João J.; Cancela Da Fonseca, Luís; Chainho, Paula; Canning-Clode, João; Pombo, Ana Margarida; Costa, José LinoA captura de isco vivo para a pesca, efetuada em sedimentos intertidais, tem aumentado em todo o Mundo, pois face ao incremento da procura, constitui uma importante fonte de rendimento para as populações que vivem junto à costa. Macroinvertebrados, tais como, moluscos, crustáceos e anelídeos poliquetas, entre outros, são capturados em muitos sistemas estuarinos portugueses, sendo a dimensão real das capturas subestimada. Este é o caso das capturas de anelídeos poliquetas para utilização, quer como isco vivo, quer como suplemento alimentar em atividades de aquacultura.Com o intuito de estimar o esforço da apanha de isco, espécies-alvo, técnicas e ferramentas utilizadas nesta atividade e as características dos apanhadores (número, idade e género), foram escolhidos como locais de estudo os estuários do Tejo e do Sado e as Rias de Aveiro e Formosa, no âmbito do projeto“Anelídeos Poliquetas como Isco Vivo em Portugal: Gestão da Apanha, Importação e Cultivo”, financiado pelo Programa PROMAR. Os resultados obtidos nestes sistemas mostraram que: i) os apanhadores de moluscos bivalves foram claramente maioritários no Estuário do Tejo e nas Rias de Aveiro e Formosa.
- Polychaete annelids as live bait in Portugal: harvesting activity in brackish water systemsPublication . Cabral, Sara; Alves, Ana Sofia; Castro, Nuno; Chainho, Paula; Sá, Erica; Cancela Da Fonseca, Luís; Fidalgo e Costa, Pedro; Castro, João; Canning-Clode, João; Pombo, Ana; Costa, José LinoPolychaete annelids are some of the most heavily harvested invertebrates collected in coastal areas and estuaries for their economic value as live fishing bait or as food supplement in aquaculture activities. However, information on bait digging in Portugal is scarce or incomplete. Thus, the present study aimed at investigating the bait digging activity in the four most relevant brackish water systems in Portugal: Ria de Aveiro and Ria Formosa coastal lagoons and Tagus and Sado estuaries. Direct observations were performed in each brackish water system 1 h and a half before and after the diurnal low spring tide (< 0.8 m height), on working days. Additionally, logbooks were delivered to bait diggers and two types of surveys were conducted in every system: one to all the intertidal users and the other only to bait diggers. The estimated daily weighted number of bait diggers varied between 31 in the Tagus estuary and 69 in the Ria Formosa coastal lagoon. Diopatra neapolitana (Delle Chiaje, 1841) was the main target species in Ria de Aveiro (more than 83%), Tagus estuary (more than 60%) and Ria Formosa (more than 90%), while in Sado estuary most of the bait diggers targeted Marphysa sp. (92.6%). The highest and lowest amount of polychaete annelid catches were estimated for Ria de Aveiro coastal lagoon (almost 50 tons per year) and Tagus estuary (11 tons per year), respectively. A total annual bait catch value in these four systems was estimated as €3.84 millions. The most important brackish water systems concerning bait diggers’ number and bait captures were Sado estuary and Ria de Aveiro coastal lagoon where management measures should be considered, although managing polychaete harvesting activity is still difficult due to limited information on harvesting and on direct and indirect impacts on population dynamics.
- Relative sensitivity of soft-bottom intertidal macrofauna to increased CO2 and experimental stressPublication . Range, Pedro; Martins, M.; Cabral, Sara; Piló, David; Ben-Hamadou, Radhouan; Chicharo, Maria Alexandra Teodosio; Miguel de Sousa Leitão, Francisco; Drago, T.; Oliveira, A. P.; Matias, D.; Chícharo, LuísWe used a controlled CO2 perturbation experiment to test hypotheses about changes in diversity, composition and structure of soft-bottom intertidal macrobenthic assemblages, under realistic and locally relevant scenarios of seawater acidification. Patches of undisturbed sediment were collected from 2 types of intertidal sedimentary habitat in the Ria Formosa coastal lagoon (South Portugal) and exposed to 2 levels of seawater acidification (pH reduced by 0.3 and 0.6 units) and 1 unmanipulated (control) level. After 75 d the assemblages differed significantly between the 2 types of sediment and between field controls and the ex situ treatments, but not among the 3 pH levels tested. The naturally high values of total alkalinity buffered seawater from the changes imposed on carbonate chemistry and may have contributed to offsetting acidification at the local scale. Observed differences on biota were strongly related to the organic matter content and grain-size of the sediments, particularly to the fractions of medium and coarse sand. Soft-bottom intertidal macrofauna was significantly affected by the stress of being held in an artificial environment, but not by CO2-induced seawater acidification. Given the previously observed variations in the sensitivities of marine organisms to seawater acidification, direct extrapolations of the present findings to different regions or other types of assemblages do not seem advisable. However, the contribution of ex situ studies to the assessment of ecosystem-level responses to environmental disturbances could generally be improved by incorporating adequate field controls in the experimental design.