Reproductive biology of the Brazilian guitarfish, Pseudobatos horkelii (Müller & Henle, 1841) from southeastern Brazil, western South Atlantic

Abstract

Summary This study provides information on the seasonal occurrence, length‐width relationship, sexual development and size at first maturity of the critically endangered Brazilian guitarfish Pseudobatos horkelii in southeastern Brazil. Samples were obtained from September 2007 to August 2009 from commercial fisheries off São Paulo State coast at depths of 10–50 m, with net mesh sizes of 150 mm in the main net and 100 mm in the cod end. A total of 143 specimens (71 males, 72 females) were analyzed. Total length (TL), disc width (DW), sex and reproductive variables were recorded for each individual. Pseudobatos horkelii presents sexual dimorphism in length‐width relationships, with females attaining larger TL and DW. Females also mature at a larger TL, at 81.1% of the maximum TL, while males mature at 67.8% of the maximum TL. No specimens were captured in winter, and only a small sample size was observed in autumn. Males captured in spring and summer presented semen in the seminal vesicle, indicating that this species may reproduce in the warmer months, as already observed for other Rhinobatidae as well as for P. horkelii in southern Brazil.

Age and growth of three endemic threatened guitarfishes Pseudobatos horkelii, P. percellens and Zapteryx brevirostris in the western South Atlantic Ocean

“…Despite the occurrence and distribution of these species along the south‐east to south coast of Brazil, most of the few studies undertaken to date have focused on reproduction (Abilhoa et al ., ; Batista, ; Colonello et al ., ; Lessa et al ., ; Martins et al ., ; Rocha & Gadig, ) and feeding habits (Bornatowski et al ., ; Carmo et al ., ; Marion et al ., ). The knowledge of other aspects of their basic biology, including age and growth parameters, is fairly limited and only available for P. horkelii and Z. brevirostris in southern Brazil (Carmo et al ., ; Lessa, ; Vooren et al ., ) and for P. Percellens in north‐eastern Brazil (Nunes, ).…”

“…Despite the occurrence and distribution of these species along the south-east to south coast of Brazil, most of the few studies undertaken to date have focused on reproduction (Abilhoa et al, 2007;Batista, 1991;Colonello et al, 2011;Lessa et al, 1986;Martins et al, 2018;Rocha & Gadig, 2012) and feeding habits (Bornatowski et al, 2010;Carmo et al, 2015;Marion et al, 2011).…”

Genetic diversity in two threatened species of guitarfish (Elasmobranchii: Rhinobatidae) from the Brazilian and Argentinian coasts: an alert for conservation

“…Pseudobatos horkelii has larger body size when compared to P. percellens (Chola guitarfish) and also differs in color pattern (Bigelow & Schroeder 1953, Vooren et al 2005a. The specimen caught (467.14 mm) was an immature female with more than a year as the size at first maturity for females is 796 mm (Martins et al 2018) and they reach 400 mm after the first year (Vooren et al 2005a). Thus, our record confirms what was found out by Lessa et al (1986) and Lessa & Vooren (2007, who considered coastal waters from 10 to 20 m deep and with temperatures from 20º to 25ºC during summer as critical zones for reproduction and recruitment of this species.…”

“…Pseudobatos horkelii was an important fishing resource in the Southern Brazilian Shelf and had a significant population decline (Miranda & Vooren 2003, Vooren et al 2005b, Martins et al 2018. For this reason, the Brazilian guitarfish was categorized as "Critically Endangered" (Lessa & Vooren 2007, and its capture and marketing in Brazil were banned (BRASIL 2014).…”

First record of clasper malformation of Pseudobatos buthi (Chondrichthyes: Rhinobatidae) in the Gulf of California

“…The sperm flow could be related to the storage times of the spermatozoa in the seminal vesicle. If we consider that P. buthi is a coastal ray without long migrations, it might not store sperm like other species of the same genus (Romero-Caicedo & Carrera-Fernández, 2015;Martins et al, 2018).…”