Recursos de colección

Repositorio da Universidade dos Açores (8.391 recursos)

O Repositório Institucional da Universidade dos Açores desenvolvido no âmbito do projecto RCAAP.

ARQ - CBM - Número 28

Mostrando recursos 1 - 12 de 12

  1. Praia Grande of Príncipe Island (Gulf of Guinea): an important nesting beach for the green turtle Chelonia mydas

    Loureiro, Nuno de Santos; Carvalho, Hualton; Rodrigues, Zeferino
    The beach Praia Grande, on Príncipe Island (Gulf of Guinea, West Africa), hosts a green turtle rookery. A total of 219 clutches with an average size of 111 eggs were laid by the 88 females that nested there during the 2007-2008 nesting season. During the nesting season 2009-2010, 315 clutches, averaging 104 eggs, were laid by the 112 females that were recorded. During both seasons, nesting began in early September and lasted until late February, with a peak in December-January. In the 2009-2010 nesting season, the clutch frequency was 2.7 (SD = 1.3) and the average renesting interval 12.3 days...

  2. Occurrence of Grammicolepis brachiusculus Poey, 1873 (Pisces: Grammicolepididae) in the Azores Archipelago

    Barreiros, João P.; Machado, Leonardo F.; Vieira, Rui P.; Porteiro, Filipe M.
    Three specimens of Grammicolepis brachiusculus were caught by the commercial bottom hand and longline fisheries off Terceira and Faial Islands, Azores Archipelago. This is the first record of the species for the region, and one of few ever caught in the NE Atlantic.

  3. Aspects of reproduction in pink dentex Dentex gibbosus (Rafinesque, 1810) from the Archipelago of Madeira in the northeast Atlantic

    Alves, Adriana; Faria, Graça; Reis, Rui; Pinto, Ana R.; Vieira, Sandra
    This work describes and identifies the macroscopic, and corresponding microscopic, changes of gonads through the annual reproductive cycle of pink dentex, Dentex gibbosus, from the Madeira Archipelago. This new contribution focused on validating a macroscopic maturity scale for this species using a histological technique. A total of 906 individuals were collected from waters around the Madeira Archipelago between September 1997 and December 2008. A six-stage maturity scale based on macroscopic characteristics was used to classify the gonads. The overall ratio of males to females was 1:1.12. The annual gonad development, together with the analysis of monthly indices (gonadosomatic and hepatoso-matic)...

  4. Age and growth of the Atlantic chub mackerel Scomber colias Gmelin, 1789 off Madeira Island

    Vasconcelos, Joana; Dias, Manuel A.; Faria, Graça
    The Atlantic chub mackerel, Scomber colias Gmelin, 1789, is one of the main fisheries resources of Madeira Island. It is caught by a small and coastal purse-seine fleet that traditionally operates around the island. From January 2002 to December 2003, monthly samples of chub mackerel were collected from landings by this commercial fishing fleet. A total of 2212 sagitta otoliths were extracted for age readings from 1068 males (17.4-41.7 cm total length, TL), 1066 females (18.0-41.2 cm TL) and 78 undetermined (13.0-26.8 cm TL). A single reader aged the fishes using surface-read whole otoliths aiming to build annual age-length keys....

  5. Recruitment and growth of Megabalanus azoricus (Pilsbry, 1916) on artificial substrates: first steps towards commercial culture in the Azores

    Pham, Christopher K.; Girolamo, Mirko De; Isidro, Eduardo
    This paper reports the results of preliminary research evaluating the potential of farming Megabalanus azoricus. From March 2006 to September 2006, artificial substrates were immersed bi-monthly in a shallow water bank located in the channel separating the islands of Faial and Pico, Azores. They were monitored monthly for a period of 12 months by scuba-diving. M. azoricus rapidly colonised the immersed substrates, establishing itself as the dominant organism. Even though recruitment was observed year round, there was a peak in recruitment between June and October. The substrate immersed for the longest period (15 months) presented final densities of 1109 ind....

  6. Vegetative propagation of the endangered Azorean tree, Picconia azorica

    Martins, José; Moreira, Orlando; Silva, Luís; Moura, Mónica
    Picconia azorica (Tutin) Knobl. (Oleaceae), commonly named “pau-branco”, is an endangered tree endemic to the Azores. Vegetative propagation may be important for the preservation of this species, particularly in depauperate populations, with low seed set. The objective of this study was to evaluate effective techniques for the vegetative propagation of P. azorica by rooting of stem cuttings or by air layering. Rooting substrate, IBA concentration, and the portion of the area of the terminal leaf pair kept on stem cuttings, when tested in early spring (semi-hardwood cuttings) and autumn (hardwood cuttings) failed to produce any rooted cuttings. In contrast, air...

  7. Altered inorganic composition of enamel and dentin in mice teeth chronically exposed to an enriched mineral environment at Furnas, São Miguel (Azores)

    Cunha, Luís; Zanon, Vittorio; Amaral, André; Ferreira, José; Rodrigues, Armindo
    Active volcanic environments pose a multifactorial stress challenge to local organisms, including the domestic mouse Mus musculus. Energy-dispersive X-ray microanalysis was used to determine the elemental composition of lower incisor enamel and dentin from Mus musculus inhabiting the hydrothermal field at Furnas volcano in the Azores (Portugal). Elemental concentration for Ca, P, Na and Cl was found to be significantly different in mice from the volcanic site when compared to an unexposed group. Enamel surface was differently coloured; animals from the volcanic site showed a prominent yellow/red coloration when compared to the unexposed group, probably due to mineral deposition in...

  8. Age and growth of the alfonsino Beryx decadactylus (Cuvier, 1829) from the Azores, Madeira and Canary Islands, based on historical data

    Krug, Helena; Carvalho, Dalila; González, José A.
    Age and growth of the alfonsino Beryx decadactylus from the Azores, Madeira and Canary Islands were studied based on otolith readings. Alfonsino otoliths are thin and show clear annual growth rings. Specimens ranged in size from 21.0 to 50.0 cm fork length (aged 2 to 10 years) in the Azores, 20.0 to 45.0 cm fork length (1 to 11 years) in Madeira, and 21.0 to 44.0 cm fork length (0 to 9 years) in the Canary Islands. No significant differences in growth parameters were found between males and females in any of the three archipelagos. [...].

  9. Predation on roseate tern eggs by European starlings in the Azores

    Neves, Verónica C.; Panagiotakopoulos, Sotirios; Ratcliffe, Norman
    Predation by the European starling (Sturnus vulgaris) was the main reason for roseate tern (Sterna dougallii) hatching failure on Vila islet, Azores, one of the species’ largest colonies in Europe. Observations showed that single or small groups of starlings were responsible for predation events and that tern nest defense against starlings was generally ineffective. Daily nest survival rate was 94.2% in 2002 and 90.0% in 2003. Nesting success was estimated using a simulation model that allowed for renesting following failure and was 0.42 in 2002 and 0.17 in 2003. These values are considerably lower than the 0.97 nesting success at...

  10. First record of Craspedacusta sowerbii Lankester, 1880 (Cnidaria: Limnomedusae) in the Azores

    Raposeiro, Pedro M.; Ramos, João; Costa, Ana C.
    [...]. This short communication, reporting the occurrence of C. sowerbii in the Congro Lake (São Miguel), is a result of the ongoing monitoring work of freshwater ecosystems performed by the University of Azores (e.g Gonçalves et al. 2008; Raposeiro & Costa 2009). Intense sampling has been carried out for the last six years in freshwater systems, but only now did we find this species.

  11. New records of marine invertebrates from the coast of Senegal

    Wirtz, Peter
    During dives at the coast of Senegal, in the vicini-ty of NGor Island, several marine invertebrate species were observed that apparently have not yet been recorded from this area.

  12. Notes on free living marine nematodes from the Canary Islands: the genus Daptonema

    Riera, Rodrigo; Núñez, Jorge; Brito, María del Carmen
    Two species of Daptonema, D. fistulatus (Wieser & Hopper, 1967) and D. hirsutum (Vitiello, 1967) from soft substrates in Tenerife are recorded for the first time for the Ca-nary Islands. These species are described and geographical variability is discussed. Fur-thermore, meristic and ecological data are presented.

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