Reproductive biology of the smoothback angel shark, Squatina oculata (Elasmobranchii: Squatinidae), from the coast of Senegal (eastern tropical Atlantic) C. Capape¤ *, A.A. Seck O , A. Gueye-Ndiaye P , Y. Diatta P and M. Diop P *Laboratoire d’Ichtyologie, case 102, Universite¤ Montpellier II, Sciences et Techniques du Languedoc, 34095 Montpellier cedex 05, France. O Muse¤ e de la Mer, Institut fondamental d’Afrique noire Cheikh Anta Diop, Gore¤ e, Se¤ ne¤ gal. P De¤ partement de Biologie Animale, Faculte¤ des Sciences et Techniques, Universite¤ Cheikh Anta Diop de Dakar, BP 5005, Dakar, Se¤ ne¤ gal. *Corresponding author, e-mail: capape@univ-montp2-fr Two species of genus Squatina were recorded o¡ the coast of Senegal and Squatina oculata is the most commonly caught in the area. Adult males and females studied were over 820 and 890mm total length (TL) respectively, with the largest male and the largest female recorded being1450mm and 1570mm and weighed 37kg and 39kg respectively. The females were signi¢cantly heavier than the males. Size at birth was between 226 and 266mm and weight at birth between 129 and 159g. Weight of ripe oocytes ranged from 87.65 to 117.60 g (mean SD 101.73  8.65). Gestation lasts one year minimum. Squatina oculata is a lecithotrophic species. Counts of ripe oocytes, eggs, embryos and fully developed foetuses showed that ovarian fecundity is signi¢cantly higher than uterine fecundity. The former ranged from 8 to 20 (mean SD 12.04 5.80), the latter from 3 to 8 (mean SD 6.22 3.41). There is no relationship between size and the categories of fecundity. Adult males and females were more common than the other categories of specimens landed. Among adults, females were more numerous than males, mainly gravid specimens. INTRODUCTION Two species, Squatinaaculeata and S.oculata, are regularly captured o¡ the coast of Senegal (Capape¤ et al., 1994). Investigations made during several years in craft ¢sheries from Cape Verde Peninsula o¡ered the opportunity to collect specimens and to complete preliminary data (Capape¤ et al., 1994, 1999a). In this paper, details are given on size at sexual maturity, size at birth, reproduction, fecundity and sex-ratio of the smoothback angel shark. These data are compared with previous data provided by Capape¤ et al. (1990) on S.oculata caught o¡ Tunisian coasts. MATERIALS AND METHODS The smoothback angel sharks (Figure 1A^C) were caught o¡ the Cape Verde Peninsula from 1994 to 2000. A total of 214 specimens were examined, including 91 males and 123 females. These specimens were generally captured by demersal gill nets and by anglers, in the shallow coastal waters at a depth of 80m maximum, on sandy-muddy bottoms, rarely among macroalgae. They were landed at the ¢shing-sites of the Cape Verde Peninsula, but most of our observations were made at Ouakam, 5 km from Dakar (Figure 1D). The monthly collection, the sex and the condition of the observed specimens are presented in Table 1. In addition, 74 embryos and 17 foetuses were studied. Embryos still had an umbilical stalk and a yolk stalk. These features were completely resorbed in fully developed foetuses. A scar marked the place of the umbilical stalk. The yolk stalk was reabsorbed in an internal vitelline vesicle. The specimens were measured to the nearest millimetre for total length (TL) following Compagno (1984). They were weighed to the nearest gramme. Measurements also included clasper length (CL, mm) from the forward rim of the pelvic girdle to the tips of claspers according to Collenot (1969), the diameter of ripe and developing oocytes. All the oocytes, the embryos and the fully devel- oped foetuses were weighed. They were removed from the ovaries and the uteri and then measured and weighed. Foetuses were sexed and embryos, when possible. The onset of sexual maturity was determined by the relationship between CL and TL. The linear regression was expressed in decimal logarithmic coordinates. Corre- lations were assessed by least-squares regression. Bass et al. (1975) and Stevens & Lyle (1989) noted that claspers of juveniles are short and £exible; they added that males are adult when claspers are rigid, elongated and calci¢ed. These were veri¢ed in S. oculata in order to avoid under- estimation of size at maturity. Size of females at sexual maturity was determined from the condition of ovaries and the morphology of the reproductive tract. Three categories of females were distinguished as well as in males. To investigate the embryonic development and the role of the mother during gestation, a chemical balance of development (CBD) was considered. The CBD is based on the mean dry weight of fertilized eggs and fully developed foetuses. The CBD can be computed as the mean dry weight of fully developed foetuses divided by the mean dry weight of fertilized eggs. Water content of 50% ova and 75% in fully developed foetuses can be taken as standard values, based on chemical analyses of the J.Mar.Biol.Ass.U.K. (2002), 82, 635^640 Printed in the United Kingdom Journalofthe Marine Biological Association ofthe United Kingdom (2002)