Reproduction of the angular angel shark (Squatina guggenheim): geographic differences, reproductive cycle, and sexual dimorphism

Abstract

Colonello, J. H., Lucifora, L. O., and Massa, A. M. 2007. Reproduction of the angular angel shark (Squatina guggenheim): geographic differences, reproductive cycle, and sexual dimorphism. – ICES Journal of Marine Science, 64: 131–140. The reproductive ecology of Squatina guggenheim from two coastal areas in South America is analysed. In both sexes, individuals from ER (El Rincón coastal system, the more southern area) attained a larger maximum total length (LT) and a heavier weight at a given length than those from LP (La Plata River estuary). Females from ER mature at a significantly larger LT than females from LP. These patterns could be explained by an advantage of larger body size at higher latitudes in providing more reserves for winter, because individuals from ER have a larger liver than those from LP. Spines in the outer part of the pectoral fins were observed only in adult males. Fecundity increased with female total length. Females have a 3-y reproductive cycle, consisting of 10–12 months of gestation and 2 y of oocyte maturation. The embryonic growth fits the Gompertz model. Birth is in November or December, as inferred from embryo size and the presence of neonates and young of the year. Densities of S. guggenheim in LP peaked in spring and summer along the Uruguayan coast, suggesting a seasonal movement perpendicular to the shore. The reproductive pattern found suggests a population with low productivity.

Phylogeography from South-Western Atlantic Ocean: Challenges for the Southern Hemisphere

“…Like other benthic elasmobranchs, they tend to have low dispersal capability, which usually result in specimens from nearby areas which have almost no mixing. As this restricted mixing may produce different life history parameters, it is important to study possible life history differences within angel shark species, even at small geographic scales (Colonello et al, 2007). Present phylogeographic approach based on cyt-b sequences in S. guggenheim from three different collecting sites from the Río de la Plata mouth and its Maritime Front as a part of the Southwestern Atlantic continental shelf and the Atlantic coast (Fig.…”

Reproductive biology of the eyespot skate Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae) an endemic species of the Southwestern Atlantic Ocean (34ºS - 42ºS)

“…In elasmobranchs with wide geographic distribution, the same species can display an increment in life history patterns with increase in latitude (Templeman, 1987;Chiaramonte, Pettovello, 2000;Yamaguchi et al, 2000;Frisk, Miller, 2006;Colonello et al, 2007b). There are many hypotheses to explain this fact, these variations could be a consequence of oceanographic conditions, the effect of fishing pressure (Mabragaña, Cousseau, 2004), or the result of phenotypic plasticity (Licandeo, Cerna, 2007).…”

“…Oddone, Vooren (2005) studied the reproductive biology of A. cyclophora in southern Brazil between 100 and 300 m depths, and later, Oddone et al (2008) complemented the reproductive studies of this species in southeastern Brazil, up to 146 m depth. In Argentina, Estalles et al (2011) reported estimates of size at maturity for males and females of A. cyclophora in the San Matías Gulf (41°S-42°S), but there is no information on reproductive variables in the area between 34°and 42° S. Also, like other elsamobranchs (Chiaramonte, Pettovello, 2000;Mabragaña, Cousseau, 2004;Colonello et al, 2007b), a latitudinal gradient in the maximum TL and size at maturity has been noted for A. cyclophora (Oddone, Vooren, 2005;Oddone et al, 2008;Estalles et al, 2011).…”

Sexual development and maturity scale for the angel shark Squatina squatina (Elasmobranchii: Squatinidae), with comments on the adequacy of general maturity scales

“…Other species in the genus with 2 functional ovaries are the sawback angel shark S. aculeata (Capapé et al 2005), the African angel shark S. africana (Bass et al 1975), S. argentina (Vooren & da Silva 1991), the smoothback angel shark S. oculata (Capapé et al 2002) and the ornate angel shark S. tergocellata (Bridge et al 1998). This characteristic, however, is not consistent in the genus, and several species have been reported with only the left complex active: S. argentina (Cousseau 1973), S. guggenheim (Vooren & da Silva 1991, Sunyem & Vooren 1997, Colonello et al 2007, Awruch et al 2008, the hidden angel shark S. occulta (Vooren & da Silva 1991, Sunyem & Vooren 1997, S. dumeril (Merriman & Olsen 1949, Backus 1957, Hoese 1962, Baremore 2010 and S. californica (Natanson & Cailliet 1986). Cousseau (1973) and Vooren & da Silva (1991) revealed a different functionality for each studied distribution of S. argentina.…”