Reproductive biology of the skates Sympterygia acuta Garman, 1877 and S. bonapartii Müller & Henle, 1841 (Chondrichthyes: Rajoidei) in south Brazil

Abstract

The present study analyzed the sexual development, sizes at maturity and morphometric relationships for both sexes of Sympterygia acuta and S. bonapartii, endemic of south-western Atlantic Ocean. The examined specimens were obtained through research cruises and commercial fishing trips, during 2011 and 2012, along the southern Brazilian coast, in latitudes ranging from 34°28'S to 31°29'S and at depths between 15 and 142 m. Significant differences (p<0.05) in S. bonapartii and in S acuta between sexes for the relationships total length (cm) -disc width (cm) and total length -total/eviscerated weight (g) respectively, demonstrated sexual dimorphism during the development in both species. The estimated size at maturity for males and females, respectively, were 46.1 and 44.7 cm, for S. acuta, and 58.4 and 59.9 cm, for S. bonapartii. A decrease in size at maturity for both sexes was observed in S. acuta and females of S. bonapartii of the southern coast of Brazil, respect to previous studies carried out over the last 30 years.O presente estudo analisou o desenvolvimento sexual, os tamanhos de maturidade e as relações morfométricas para ambos os sexos das espécies Sympterygia acuta e S. bonapartii endêmica do sudoeste do Oceano Atlântico. Os indivíduos foram coletados em cruzeiros de investigação e viagens de pesca comercial durante 2011 e 2012 ao longo da costa do Sul do Brasil em latitudes que variam de 34°28'S a 31° 29'S, e em profundidades entre 15 e 142 m. Houve diferenças significativas entre sexos para S. bonapartii (p <0,05) e S acuta nas relações comprimento total (cm) -largura do disco (cm) e comprimento -peso total e comprimento total -peso eviscerado (g), demonstrando dimorfismo sexual durante o desenvolvimento em ambas as espécies.Os tamanhos estimados de maturação para machos e fêmeas, respectivamente, foram iguais a 46,1 e 44,7 cm para S. acuta; e 58,4 e 59,9 cm para S. bonapartii. Uma diminuição nos tamanhos de maturidade para ambos os sexos foi observada em S. acuta e fêmeas de S. bonapartii da costa Sul do Brasil, com relação a estudos realizados há 30 anos.

Morphology and dynamics of male gametogenesis in Sympterygia bonapartii (Chondrichthyes, Rajidae) from Northern Patagonia

“…Our results show that the length and hardening of the claspers are not only related to the macroscopic aspect of the genital organs, but it also agrees with the histological events (spermatogenesis and spermiogenesis) that occur inside the testis, thus sustaining the conception that length growth and hardening of the claspers are a valid and simple criteria to determine maturity on board, at least for S. bonapartii. The size range observed in S. bonapartii is consistent with those reported by other authors for the same species (Mabragaña et al, 2002;Oddone & Velasco, 2004;Cousseau et al, 2007;Jañez & Sueiro, 2007;Basallo & Oddone, 2014). Likewise, the seasonal frequency of maturity stages here observed, does not differ from previous reports regarding to S. bonapartii for the El Rincón salt marsh area, near the Bahía Blanca estuary (Mabragaña et al, 2002).…”

“…On the other hand, Mabragaña et al (2002) estimated that the size at maturity for males inhabiting Uruguay and the north coast of Argentina, was about 65 cm. The size at first sexual maturation calculated in this work is within the ranges established by Oddone & Velasco (2004) and Basallo & Oddone (2014) but is clearly below the size reported by Mabragaña et al (2002). Even though this could indicate that the population is exposed to some anthropic pressure, it could exist other biological or environmental factors that could be affecting this fish population locally.…”

“…Oddone & Velasco (2004) calculated that the size at first sexual maturation was in the range between 52 and 57 cm or males inhabiting the South of Brazil, while Basallo & Oddone (2014) Figs 11-17, Sympterygia bonapartii Müller & Henle, 1841. Fig.…”

Reproductive biology of Psammobatis rutrum (Chondrichthyes: Arhynchobatidae) in south Brazil, south‐west Atlantic

“…Ovarian fecundity was estimated as 1–12 follicles, representing a lower value in comparison with other rajoids (Oddone et al, ; Basallo & Oddone, ). Species of the genus Psammobatis generally have low ovarian fecundity when compared with other Rajoidei.…”

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

“…According to previous studies, it presents a seasonal reproductive cycle in the wild while it is able to reproduce throughout the year in captivity (Mabragaña et al, 2002;Jañez, Sueiro, 2009). Estimations of size at maturity also vary among studies and they were performed in the northern area of its distribution (Mabragaña et al, 2002;Oddone, Velasco, 2004; Díaz 2 e160022[2] Andrade, 2011;Basallo, Oddone, 2014). In Patagonia, the biological information on the species is scarce.…”