Percorrer por autor "Almada, Frederico"
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- The golden mackerel: first report of a xanthic Mediterranean horse mackerel Trachurus mediterraneus (Steindachner, 1868) from Sines, PortugalPublication . Vasco-Rodrigues, Nuno; Santos, Simão; Espírito-Santo, Cristina; Almada, FredericoIn this study, a single xanthic case of the Mediterranean horse mackerel Trachurus mediterraneus is reported. The individual, with a total lenght (TL) of 306 mm, was captured off Sines (Portugal) in March 2018, by a local fishing boat, using a seine net. This represents the first record of xanthism for this species and for any species of mackerel. The specimen is described here and compared with those of normal pigmentation. Considerations about the paucity of records for this or similar species are presented here, and the possibility of this condition being more frequent than previously thought is discussed.
- Ichthyofauna of the Selvagens Islands. Do small coastal areas show high species richness in the northeastern Atlantic?Publication . Almada, Frederico; Abecasis, David; Villegas-Ríos, David; Henriques, Sofia; Pais, Miguel P.; Batista, Marisa; Costa, Bárbara Horta; Martins, Joana; Tojeira, Inês; Rodrigues, Nuno Vasco; Araújo, Ricardo; Souto, Miguel; Alonso, Hany; Falcón, Jesús M.; Henriques, Filipe; Catry, Paulo; Cabral, Henrique; Biscoito, Manuel; Almada, Vitor C.The Selvagens Islands are located in the northeastern Atlantic between the Canary Islands and Madeira Island. As a result of their small size, remote location and harsh sea conditions only a few studies have been conducted to describe their marine species diversity. We were able to identify 29 new coastal fish species, an increase of 33% in the ichthyofauna described for these islands (n = 88). There is a prevalence of species with tropical affinities and only 2.3% (n = 2) are endemic to Macaronesia. Considered a stepping-stone colonization vector from the nearest continental shore, as proposed by other authors for this region, the Selvagens Islands host 34.1% of the ichthyofauna described for the much larger Canary Islands (nspecies = 258, submerged area nSelvagens Is. = 2.3%) and 47.3% of the ichthyofauna described for the more distantly located Madeira Island (nspecies = 186, submerged area nSelvagens Is. = 17.9%). Interestingly, 6.8% (n = 6) of the species failed to bridge the gap between the Selvagens Islands and Madeira Island. Data collected so far showed no trend toward an increasing number of species with high dispersal capability. The Selvagens Islands are an example of a high coastal species diversity occurring even in very small areas of the northeastern Atlantic Ocean.