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  • Size does matter: An assessment of reproductive potential in seahorses
    Publication . Faleiro, Filipa; Almeida, Armando; Re, Pedro; Narciso, Luís
    In most animals, the mother plays the key role in reproduction, but male pregnancy in seahorses raises the question of whether the female still is the only determinant of offspring size or if she shares some responsibility with the male. This study evaluates the effects of both male and female size on the reproductive output of the long-snouted seahorse, Hippocampus guttulatus. Results demonstrated that, with regard to reproductive potential, the bigger the better. Seahorses preferred similar-sized or larger mates. Larger females produced bigger eggs with larger yolk reserves. Larger males had larger brood pouches, but did not produced larger broods. Male size was negatively correlated with embryo density and positively correlated with juvenile size. Both parents proved to play a decisive role in the reproductive output of this species. Newborn juveniles from the same parents were 15% bigger and 30% heavier when incubated in smaller and lower-density broods. This trade-off between the number and size of embryos inside the brood pouch clearly indicates a limited carrying capacity of the male, and demonstrates that the size of newborn seahorses can be, in part, paternally determined.
  • First record of Polymixia nobilis Lowe, 1836 (Polymixiidae) for Eastern Central Atlantic, São Tomé Island
    Publication . Almeida, Armando J.; Alves, Maria Judite
    One specimen of Polymixia nobilis Lowe, 1836, (SL = 291 mm) was bought from local fishermen in 1955, who caught it with a bottom line off the north-eastern coast of São Tomé Island. This is the first record of this species for Eastern Central Atlantic (São Tomé Island, Gulf of Guinea, Atlantic Ocean).
  • Mangrove fish of São Tomé Island (Gulf of Guinea): new occurrences and habitat usage
    Publication . Félix, Pedro; Chainho, Paula; Lima, R. F.; Costa, José Lino; Almeida, Armando; Domingos, Isabel; Brito, A. C.
    Mangroves are recognised as important nursery and feeding areas for resident and inshore fish species. However, the importance of West African mangroves to the life cycle of fish communities remains poorly studied. The present study is the first record of fish species in tropical insular mangroves for this region and its aim was to assess habitat usage by fish species. Two mangroves of São Tomé Island (Praia das Conchas and Malanza) were sampled with a multihabitat approach and using different fishing gear to maximise the diversity of fish species collected. Several environmental parameters were also measured. Both mangroves are nursery and opportunistic feeding grounds for fish species, as well as settlement areas for resident species. The highest number of both juveniles and adults (inshore and residents) was observed at the Malanza mangrove, which is also the largest and has the highest habitat heterogeneity. Four new occurrences were reported for the São Tomé and Principe area, namely Pomadasys jubelini, Bostrychus africanus, Dalophis cephalopeltis and the introduced species Oreochromis mossambicus.