IPMA - DMRM - Artigos Científicos
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- EXPERIÊNCIA PILOTO PARA AVALIAR A SOBREVIVÊNCIA DA CAVALA (Scomber colias) PÓS-SLIPPING NA PESCA DO CERCOPublication . Bandarra, Cidália; Silva, Alexandra; Instituto Português do Mar e da Atmosfera, I.P.Under the scope of Sardinha2020 Project, a pilot experiment was carried out to study the survival rate of chub mackerel (Scomber colias) after slipping. Slipping is the release of unwanted capture in purse seining, by lowering the head rope of the net and rolling over the fish back into the water. In Southwestern Portugal (Sesimbra), during the summer of 2020, the experiment was carried out using 2 small net pens (control and slipping treatment) moored in the open ocean, where fish slipped by a purse-seiner were monitored daily to evaluate the survival rate of chub mackerel. The control pen contained fish slipped in the initial moments of slipping (less crowding and density), and the slipping treatment contained fish aggregated at high densites towards the end of the operation. The results of this experiment revealed a high survival rate of chub mackerel on both net pens, reaching 94% in the slipping treatment and 97.7% in the control, after a 5 day trial period. For horse mackerel (Trachurus trachurus), unintentionally introduced inside the nets, this study revealed a reduced survival rate of 40% in the slipping treatment compared to 85% in the control net, suggesting that the slipping activity for this species could induce high motalities. In this study, individuals’ condition factor and caudal indexes, as well as physical conditions were evaluated during the experiment. It was verified that, for both species and for both control and slipping treatment, dead individuals, in general, presented more deterioration ofthese conditions, compared to the survivors. This work aims to evaluate the survival rate of chub mackerel and horse mackerel after purse seine slipping. This work is novel for both species, thus we expect this new knowledge, will be an important contribution to improve stock assessment of these species.
- Ocean kinetic energy and photosynthetic biomass are important drivers of planktonic foraminigera diversity in the Atlantic OceanPublication . Rufino, Marta M.; Salgueiro, Emília; Voelker, Antje H. L.; Polito, P. S.; Cermeno, Pedro; Abrantes, FIt is hypothesized and tested for the first time, that the large-scale diversity patterns of foraminifera communities are determined by sea surface temperature (ISST, representing energy), Chl-a (a surrogate for photosynthetic biomass) and ocean kinetic energy (as EKE). Alpha diversity was estimated using species richness (S), Shannon Wiener index (H), and Simpson evenness (E), and mapped using geostatistical approaches. Beta diversity was studied through species turnover using gradient forest analysis (59% of the variation). The geographic location of the transition between the four main biogeographic zones was redefined based on the results of beta diversity analysis and incorporating the new datasets, identifying the major marine latitudinal gradients, the most important upwelling areas (Benguela Current, Canary Current), the Equatorial divergence, and the subtropical fronts (Gulf Stream-North Atlantic Drift path in the north and the South Atlantic current in the south). We provide statistical proof that energy (SST), food supply (Chl-a), and currents (EKE) are the main environmental drivers shaping planktonic foraminifera diversity in the Atlantic ocean and define the associated thresholds for species change on those variables.
- Fluxos de nutrientes em viveiros de ameijoa na Ria FormosaPublication . Falcão, Manuela; Vale, CarlosA Ria Formosa é um sistema lagunar separado do mar por um cordão litoral com várias ilhas e canais. A ocorrência quinzenal de marés com amplitudes de três metros dá origem a extensas áreas interdidais ocupadas com culturas extensivas de ameijoa, Ruditapes decussatus. Em diversas áreas foram colhidos box-cores e incubados em laboratórios durante 15 dias, em camaras transparentes com água da Ria. As experiências foram realizadas a níveis constantes de O2, com diferentes concentrações de nutrientes na água, com luz natural e com ausencia permanente de luz. Foram determinadas as concentrações em silicatos, fosfatos, nitratos e amónia.
- Preliminary report on the characterisation of bottom sediment on nephrops grounds off the southwest and south-eastern costa of Portugal : study carried out during the June 2004 crustacean surveyPublication . Leotte, F.; Gaudêncio, Maria José; Silva, C.; Guerra, MirianCruzeiro realizado em Junho de 2004 a bordo do navio de investigação científica do IPIMAR para estudar as características físicas e biológicas da lagosta da Noruega. A análise dos dados recolhidos durante os levantamentos de crustáceos identificou uma área ao largo da costa sudeste de Portugal com grande abundância de lagostas da Noruega adultas e juvenis.
- Um Novo Astacidae para a Fauna Portuguesa : Procambarus clarkii (Girard,1852)Publication . Ramos, Maria Alice; Pereira, Teresa GamaNeste trabalho assinala-se a presença em Portugal da espécie Procambarus clarkii (Girard, 1852), a qual se pensa ser o resultado de uma introdução ocasional, ou provavelmente provir dos efluentes de espanha, onde foi introduzido voluntariamente para cultura.