28 research outputs found

    Apolar Compounds in Seaweeds from Fernando de Noronha Archipelago (Northeastern Coast of Brazil)

    Get PDF
    Hyphenated techniques of gas chromatography coupled to mass spectrometer were used to determine fatty acids in eleven species of seaweeds from Fernando de Noronha archipelago. The main compounds detected in all studied species were the alcohol phytol and the fatty acids 14 : 0; 15 : 0; 16 : 0; 18 : 0; 18 : 1 n9; 18 : 2 Δ9,12; 20 : 4; 20 : 5. These fatty acids are commonly found in seaweeds present in warm regions. Thus, we found no specificity in the presence of a particular set of fatty acids and the studied species indicating that they are not useful as taxonomic indicators. However, they could be used in a comparative study with algae found in polluted area because many of the studied seaweeds are widespread and Fernando de Noronha has low human influence

    Concentration of Inorganic Elements Content in Benthic Seaweeds of Fernando de Noronha Archipelago by Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SRTXRF)

    Get PDF
    SRTXRF was used to determine As, Ba, Br, Ca, Co, Cr, Cs, Cu, Dy, Fe, K, Mn, Mo, Ni, Pb, Rb, Sr, Ti, V, and Zn in eleven seaweed species commonly found in Fernando de Noronha: Caulerpa verticillata (J. Agardh) (Chlorophyta), Asparagopsis taxiformis (Delile), Dictyurus occidentalis (J. Agardh), Galaxaura rugosa (J. Ellis & Solander) J. V. Lamouroux, G. obtusata (J. Ellis & Solander) J. V. Lamouroux, G. marginata (J. Ellis & Solander) J. V. Lamouroux (Rhodophyta), Dictyota cervicornis (Kützing), Dictyopteris justii (J. V. Lamouroux), Dictyopteris plagiogramma (Montagne) Vickers, Padina gymnospora (Kützing) Sonder, and a Sargassum sp. (Phaeophyta). Data obtained were compared to those from the analysis of other parts of the world seaweeds using different analytical techniques and were found to be in general agreement in terms of major and minor elemental components. Results provide baseline information about the absorption and accumulation of these elements by macroalgae in the area

    Movement patterns of young Caribbean reef sharks, Carcharhinus perezi, at Fernando de Noronha Archipelago, Brazil: The potential of marine protected areas for conservation of a nursery ground

    Get PDF
    The movement patterns and long-term site-fidelity of primarily juvenile Caribbean reef sharks, Carcharhinus perezi, were investigated using tag-recapture and automated telemetry at an insular nursery area, the Fernando de Noronha Archipelago, Brazil. Of the 143 externally tagged juvenile sharks (\u3c 110 cm), 22 (15.3%) were recaptured between 0 and 5 km from the site of tagging after 5-800 days at liberty, suggesting some site-fidelity in young individuals of this species. Site-fidelity and movement patterns of ten juvenile sharks ranging from 78 to 110 cm total length (TL) and one opportunistically captured adult female (224 cm TL) were also investigated for periods of up to 2 years with an array of automated telemetry receivers. Tagging and telemetry data from both inside and outside a marine protected area (MPA) show that shark abundance and activity is greatest along the part of the archipelago\u27s coastline least disturbed by human activity. Telemetry tracking also showed that juvenile reef sharks demonstrated a high degree of site-fidelity and occupied specific locations along the coast throughout the year, with some evidence of an increase in activity space with ontogeny. Sharks appeared to range more widely at night and there were no seasonal variations in habitat use. Our results suggest that MPAs may be a useful conservation tool to protect young C. perezi and potentially other reef-dwelling carcharhinid sharks during their early life history. © Springer-Verlag 2005

    Defensive strategies of neonate nurse sharks, Ginglymostoma cirratum, in an oceanic archipelago of the Western Central Atlantic

    No full text
    Two defensive tactics of neonates of nurse sharks, Ginglymostoma cirratum, are reported based on underwater observations. Described as "hiding behaviour" and "substrate resemblance", the defensive strategies were categorized according to the predominant habitat in which the individuals were found and to the behaviour displayed by the sharks in the presence of the observer. In structurally more complex habitats with a wide availability of shelters, the preferential behaviour displayed by neonates is to hide inside holes or crevices. When in open areas deprived of refuges, neonates tend to resemble arborescent coverings as seaweed banks or colonies of octocorals, which allows the use of more exposed habitats without increasing the susceptibility of capture by predators. Both aspects are relevant for a better understanding of the behaviour of neonates of G. cirratum and have important implications for identifying important habitat in nursery areas, and also for the management of this vulnerable species off South America

    Tiger shark size composition.

    No full text
    <p>Total length-frequency distribution histogram of tiger sharks caught off the Fernando de Noronha Archipelago with longline and handline gear, in 30-cm size classes. The light grey and dark grey correspond to sharks caught with handline and longline gear, respectively.</p

    Tiger shark displacement through time.

    No full text
    <p>Linear distance to the tagging site of tiger sharks tagged with SPOT tags between 30 July and 2 August 2014 off the Fernando de Noronha Archipelago across the extent of their respective tracks. Red line: shark #22; yellow line: shark #23; brown line: shark #25; orange line: shark #26.</p
    corecore