Reproductive cycle of Bolinus brandaris and penis and genital duct size variations in a population affected by imposex

Abstract

The reproductive cycle of Bolinus brandaris (Gastropoda: Muricidae) was investigated. Specimens were sampled monthly from a site off Sant Carles de la Ràpita, in the western Mediterranean, between February 1999 and March 2000. A pattern was observed in the reproductive cycle, with two reproductive peaks (April and June–July). The first stages of gametogenesis began in September for males and November for females. Mature males were found from December to April and from June to July. Maximum ripening in females was attained at the end of June and during July, coinciding with the spawning season. In May, there was a resting stage in females, and for both sexes from August to October.Males exhibited variation in penis length and vas deferens width related to the reproductive cycle. Sizes of both dimensions increased as maturation progressed. The variation was not found in imposex females.

Relative growth and reproductive cycle in two populations of Bolinus brandaris (Gastropoda: Muricidae) from northern Tunisia (Bizerta Lagoon and small Gulf of Tunis)

“…These slight differences in size distribution between collecting sites can be also explained by differences in depth, because for the same species caught in Saint Carles de la Ràpita (Catalan coast), Martín et al (1995) showed that the size distribution was significantly correlated with depth. The present results corroborate Ramón & Amor (2002), who found that both sexes were distributed from 26 mm to 52 mm SLWS. Females were more abundant at lengths between 33 and 40 mm SLWS, but the size structure was similar in both sexes.…”

“…This observation agrees with those reported for B. brandaris populations collected from Vilanova i la Geltrú and Barcelona (Spain) (Ramón & Amor 2001). In contrast, the same authors (Ramón & Amor 2002), as well as others (Vasconcelos et al 2011), reported that females were more abundant than males in populations of B. brandaris collected off Sant Carles de la Rapità (Tarragona, Spain) and from the Ria Formosa lagoon (Portugal), respectively. Differences in the sex-ratios can be explained by distinct depth distribution between sexes that might affect their availability (Ramón & Amor 2002).…”

“…Macroscopic examination of the gonads in both sexes and of the capsule gland in females was Growth and reproduction of Bolinus brandaris. performed to distinguish three maturity stages (immature, intermediate and mature) following Ramón & Amor (2002) (Figs 2-4). Briefly, in stage I (immature) the gonads of both sexes are indistinguishable from the digestive gland and females present an inconspicuous capsule gland; in stage II (intermediate) the gonads of both sexes are more developed and correspond approximately to one-third of the area of the digestive gland; in stage III (mature / ripe) males show a well developed yellowish testicle corresponding to more than half of the area of the digestive gland, whereas females have a voluminous pinkish ovary and a large whitish capsule gland.…”

“…During spawning, females lay eggs inside oothecas that attach to each other, forming large masses fixed to solid substrata on the sea bed (Ramón & Amor 2002). Like approximately 200 gonochoristic neogastropod species (Shi et al 2005;Sternberg et al 2010), B. brandaris is affected by imposex throughout its distributional range Solé et al 1998;Ramón & Amor 2001;Chiavarini et al 2003;Lemghich & Benajiba 2007;Vasconcelos et al 2010Vasconcelos et al , 2011Abidli et al 2009aAbidli et al , 2011Abidli et al , 2012.…”

“…Among previous studies performed with this muricid species, we cite the fishery and biology (Bartolome 1985), the fishery and population structure (Martín et al 1995;Vasconcelos et al 2008a), growth of hatchlings and juveniles (Ramón & Flos 2001) and adults (Vasconcelos et al in press), reproductive cycle (Ramón & Amor 2002;Vasconcelos et al 2011) and gametogenesis (Amor & Durfort 1990;Amor et al 2004). In the Mediterranean Sea, studies on the biology of B. brandaris are scarce and restricted to populations from the northern shore (Martín et al 1995;Ramón & Flos 2001;Ramón & Amor 2002). On the southern shore, such type of investigations are not available, therefore, the main objective of this study was to complete gaps of knowledge in the biology of B. brandaris from the southern Mediterranean.…”