| Summary: | Tese de doutoramento, Ciências do Mar, Universidade de Lisboa, Faculdade de Ciências, 2012 The Portuguese dogfish Centroscymnus coelolepis is a deep-water shark commonly caught in the Northeast Atlantic that shows a decreasig trend in its abundance, in special in the northern areas. Assessment of this species has been difficult due to the poor knowledge on its dynamics, including its reproductive strategy and population structure. The present thesis pretends to fill some gaps by providing scientific support to be used in the advisement of this resource. C. coelolepis presents two peaks of ovulation in each year (March-May and September-November). Each female produces, in average, 12 embryos. The embryonic development may last two years and analyses suggest that only water and minerals are transferred from the mother to the embryo. Thus, C. coelolepis is a viviparous species, strictly lecithotrophic, depending only on yolk reserves for the embryonic development. Both males and females are able to store sperm: in males, sperm is stored in the seminal vesicle from early maturity stages until mating; mature, pregnant, resting and regenerating females store sperm in the terminal zone of the oviducal gland within sperm storage tubules, possibly for a long time period. A fraction of the population seems to distribute in areas where the fishery has no impact, due, in part, to the existence of sexual segregation among specimens. This species can be aged using dorsal spines. The population under study presents slow growth rates, high longevity and late maturity. The COI gene has proved to be an adequate marker to identify C. coelolepis, when doubts on identification arise. The hypothesis of existence of a single population in the Northeast Atlantic was not rejected, after the analysis of control region and six microsatellite markers. However, the possibility of existence of philopatry is not excluded. O carocho, Centroscymnus coelolepis, é um tubarão de profundidade com uma distribuição global, ocorrendo nos oceanos ...
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