Reproductive biology of the dusky grouper (Epinephelus marginatus) at the southern limit of its distribution in the south-western Atlantic

Abstract

We investigated the reproductive parameters of a dusky grouper Epinephelus marginatus population at the southern limit of its distribution in the south-western Atlantic. The analysed specimens were captured between January 2008 and April 2011 at Carpinteiro Bank (CB) (32°16′S; 051°47′W), a seamount located at the 20 m isobath ~16 nautical miles from the coast. The gonads of a total of 201 individuals (184 females, 16 males and 1 individual in sexual transition) with a total length (TL, mm) between 278 and 1160 mm were analysed microscopically. Histological analyses of the gonads suggested that the species is a partial spawner with a long spawning period (between November and March) and with a reproductive peak between November and January. The average female length at first maturity (L50) was 496 (TL, mm). We also observed partially spawned ovaries and partially spawned testes, which indicated reproductive activity, and we noted the presence of hyalinised follicles. These findings reveal that CB is the southernmost portion of the south-western Atlantic in which the dusky grouper reproduces. Additionally, an inshore-offshore comparison suggested that deeper (>20 m) rocky bottoms, such as the studied seamount, constitute higher quality habitats for this species when compared with littoral (<5 m) rocky reefs.

Prolonged estuarine habitat use by dusky grouper Epinephelus marginatus at subtropical latitudes revealed by otolith microchemistry

“…Ca, respectively. As the Carpinteiro Bank (a neritic zone) has been identified as an important spawning site for E. marginatus in southern Brazil (Condini et al 2014a) and taking into consideration the close location of the littoral habitat (16 nautical miles), all individuals used in this study were assumed to belong to the same population; this assumption is corroborated by the long distances that dusky grouper larvae can disperse (>16 nautical miles; Andrello et al 2014). To reconstruct and characterize habitat use patterns of E. marginatus, we analyzed the Sr:Ca and Ba:Ca lifehistory profiles of all 72 E. marginatus individuals collected from both littoral and neritic areas.…”

Age and growth of dusky grouper (Epinephelus marginatus) (Perciformes: Epinephelidae) in the southwestern Atlantic, with a size comparison of offshore and littoral habitats

“…In the laboratory, the total length (TL) in millimeters and weight (WT) in grams of each specimen were measured, and sex was identified by a macroscopic examination of the gonads following Marino et al (2001). Male and female gonadal differences are quite clear in macroscopic examination for this hermaphroditic grouper (Marino et al, 2001;Condini et al, 2014). The Carpinteiro Bank (32°16′S; 51°47′W) ( Fig.…”

“…Additionally, fishing effort and the number of fishing boats operating in the region have increased during the last 3 decades (Cowx et al, 1998), and those changes could have resulted in the decreased availability of the older age classes of dusky grouper that we observed in this study. Another interesting finding was that approximately 40% of the fish captured offshore were immature (L 50 =496 mm TL, as estimated from Condini et al, 2014). Given the com- Table 1 Ages, number of specimens sampled (n), and means and ranges of total length (TL) and weight (WT) for dusky groupers (Epinephelus marginatus) caught at the Carpinteiro Bank in the southwestern Atlantic by small-scale fisheries from 2008 to 2011.…”

“…For our study, we followed the most recent classification (Craig et al, 2011), in which the species was retained in Epinephelus, given the absence of conclusive studies to change the genus. Another study conducted in this region revealed that the dusky grouper reproduces at offshore Carpinteiro Bank (Condini et al, 2014).…”

Reproductive strategies of the marine fishes from the southwest Atlantic Ocean: an application of histological and image processing techniques

“…The inner ARAUJO; CHELLAPPA, 2002;ANDRADE et al, 2003;FAVARO et al, 2005;FAVARO et al, 2007;SILVA et al, 2005;BESSA et al, 2007;ARAÚJO et al, 2008;ALBIERI;ARAÚJO, 2010;FÁVARO, 2010;MARQUES;FERREIRA, 2011;FÁVARO, 2011;FERNANDES et al, 2012;CASSACA et al, 2012;BRANCO et al, 2013;BEZERRA et al, 2013;DIAS, 2013;CONDINI et al, 2014;LEMOS et al, 2014;CHELLAPPA, 2014). Thus, the application of histological methods are still scarce, and some of these authors have…”