Reproductive biology of Sympterygia bonapartii (Chondrichthyes: Rajiformes: Arhynchobatidae) in San Matías Gulf, Patagonia, Argentina

Abstract

This study estimates and analyses the reproductive parameters and cycle of Sympterygia bonapartii in San Matías Gulf, northern Patagonia, Argentina. A total of 827 males and 1,299 females were analysed. Males ranged from 185 to 687 mm of total length (TL) and females from 180 to 742 mm TL. Sexual dimorphism was detected; females were larger, heavier, exhibited heavier livers, wider discs and matured at lager sizes than males. Immature females ranged from 180 to 625 mm TL, maturing females from 408 to 720 mm TL, mature ones from 514 to 742 mm TL and females with egg capsules from 580 to 730 mm TL. Immature males ranged from 185 to 545 mm TL, maturing ones from 410 to 620 mm TL and mature males from 505 to 687 mm TL. Size at which 50% of the skates reached maturity was estimated to be 545 mm TL for males and 594 mm TL for females. According to the reproductive indexes analysed, S. bonapartii exhibited a seasonal reproductive pattern. Mating may occur during winter-early spring and the egg-laying season, during spring and summer.Keywords: Elasmobranchii, Reproduction, Skate, South Western Atlantic Ocean.El presente estudio estima y analiza los parámetros reproductivos y el ciclo reproductivo de Sympterygia bonapartii en el Golfo San Matías, Patagonia norte, Argentina. Se analizaron 827 machos y 1.299 hembras. Los machos midieron entre 185 y 687 mm de largo total (LT) y las hembras entre 180 y 742 mm LT. Se detectó dimorfismo sexual; las hembras fueron más grandes y pesadas que los machos y presentaron anchos de disco, pesos de hígado y tallas de madurez sexual mayores a los de los machos. Las hembras inmaduras midieron entre 180 y 625 mm LT, las hembras en maduración entre 408 y 720 mm LT, las maduras entre 514 y 742 mm LT y las hembras con cápsulas entre 580 y 730 mm LT. Los machos inmaduros midieron entre 185 y 545 mm LT, los machos en maduración entre 410 y 620 mm LT y los maduros entre 505 y 687 mm LT. La talla media de madurez sexual fue estimada en 545 mm LT para los machos y 594 mm LT para las hembras. De acuerdo con los índices reproductivos analizados, S. bonapartii se reproduce estacionalmente. El apareamiento ocurriría durante el invierno y la primavera y la temporada de puesta durante la primavera y el verano.

Growth and reproduction in captivity unveils remarkable life-history plasticity in the smallnose fanskate, Sympterygia bonapartii (Chondrichthyes: Rajiformes)

“…In this study, S. bonapartii did not reach the maximum sizes recorded in the wild. Wild females attained 78.0-80.8 cm TL, and males 72.9-74.6 cm TL in Uruguay and north Argentina coastal waters (Mabragaña et al, 2002;Hozbor, Massa, 2015) whereas the maximum sizes recorded in San Matías Gulf, north Patagonia, were 74.2 cm and 68.7 cm TL for females and males, respectively (Estalles et al, 2017). In contrast, the maximum sizes reached at Temaikèn Aquarium were 64.5 and 58.2 cm TL in females and males, respectively.…”

“…Earlier work has estimated female size at maturity at 63.6-65.5 cm TL off Uruguay and north Argentina (Mabragaña et al, 2002;Oddone, Velasco, 2004), 59.9 cm TL in south Brazil (Basallo, Oddone, 2014) and 59.4 cm TL in San Matías Gulf, north Patagonia (Estalles et al, 2017). The average size of first generation captive-born males yielding embryonated eggs for female tankmates was 54.0 cm TL, which is within the range of estimates for male size at maturity in the wild (52.0-65.1 cm) (Estalles et al, 2017). No difference in size at maturity between captive and wild individuals has been reported previously for batoids (Henningsen, Leaf, 2010).…”

“…In the case of S. bonapartii, this seasonality differs from that recorded in the wild. Based on records of gonadosomatic index, oviducal gland index and diameter of ovarian follicles of mature females, the egg laying season in the wild was estimated to be September-October through February (spring-summer) (Mabragaña et al, 2002;Estalles et al, 2017). In contrast, laying activity at Temaikèn Aquarium started earlier, from June-July through January.…”

“…The smallnose fanskate, Sympterygia bonapartii Müller & Henle, 1841, occurs regularly from off Santos, Brazil (24° S, Menni, Stehmann, 2000) to Santa Cruz Province, Argentina (49° S, Cousseau et al, 2007), from the intertidal to 100 m deep (Menni, Stehmann, 2000). The reproductive biology of S. bonapartii has been extensively studied and parameters such as size at maturity and fecundity are well known (Mabragaña et al, 2002;Oddone, Velasco, 2004;Oddone, Vooren, 2008;Galíndez et al, 2010;Díaz-Andrade et al, 2013;Basallo, Oddone, 2014;Moya et al, 2015;Estalles et al, 2017). Recently, growth parameters and age at maturity of this species in the wild have been estimated (Hozbor, Massa, 2015).…”

Size at sexual maturity, seasonal variation by maturity stages, and fecundity of the spotted round ray (Urobatis maculatus) and the thorny stingray (Urotrygon rogersi) from the northern tropical eastern Pacific

“…The likely reason for this observation was that in that study the individuals of U. rogersi come from artisanal shrimp trawls in shallow waters (≤10 m depth), whereas in the present study, the individuals of this specie were caught at depths of 9–64 m; thus such differences may result in different cohorts of these populations being caught (e.g., Bustamante & Bennett, 2013; Nakano & Seki, 2003). However, other factors could have also influenced these observed differences in the DW 50 between regions, for example, the sample size (Bellodi et al, 2016; Da Silva et al, 2018), the structure of the data concerning the proportion of mature individuals in each size class (Chen & Paloheimo, 1994; Molina & Cazorla, 2015; Trippel & Harvey, 1991), the criteria for assigning maturity, mainly when performing macroscopic observation of reproductive structures (Martin & Cailliet, 1988; Oviedo‐Pérez et al, 2014; Tagliafico et al, 2016) or selectivity of the fishing gear (Estalles et al, 2017; Martins et al, 2018; Tagliafico et al, 2012). The differences could also be related to the existence of subpopulations with different natural variability in maturity (Alkusairy & Saad, 2017; Araújo et al, 2016; Da Silva et al, 2018; Snelson Jr. et al, 2008), caused by different oceanographic and environmental conditions (Girard & Du Buit, 1999; Saadaoui et al, 2015; Yamaguchi et al, 2000), or even fishing pressure (Aranha et al, 2009; Fahmi et al, 2009; Serra‐Pereira et al, 2015).…”