Ciclo reproductivo de Tagelus plebeius(Bivalvia) en el estuario del Rí­­o Ceará, Nordeste do Brasil

Abstract

The bivalve Tagelus plebeius is an infaunal and eurihaline species found mainly in tropical intertidal environments. Although there are studies on the reproductive cycle of bivalves, there is still little research on the reproductive biology of most species found on the Brazilian coast, which are important for the balance of these ecosystems and represent a complementary economic activity or of subsistence for artisanal fishermen. The reproductive cycle of T. plebeius was described from a population located in the Ceará river estuary, in the municipality of Fortaleza, Ceará, Brazil. During 15 months (April/2006 to June/2007), 450 specimens were collected and the gonads were examined by routine histology. The stages of gametogenic development were defined with the following phases: Follicular Organization (OF), Proliferation (P), Maturation/Initial Elimination (M/E), Advanced Elimination (EA) and Cellular Atresia (AC) for both sexes. The species has a continuous reproductive cycle, presenting mature and spawned specimens throughout the year. However, periods of higher gametes release were observed in the second half of the year. Among the factors that would be influencing the reproductive cycle of T. plebeius in the Ceará river estuary, salinity seems to be the main one, since a significant correlation was found between this factor and the phases Maturation/Initial Elimination and Cell Atresia.

RAINFALL SEASONAL VARIATION EFFECT ON THE REPRODUCTIVE CYCLE OF THE BIVALVE Phacoides pectinatus FROM SEMIARID COAST OF BRAZIL

“…The occurrence of reproductive synchrony between different species in the same region reinforces the influence of environmental variables on the life history of the species. Other bivalves that coexist with P. pectinatus also presented reproductive synchrony, such as Tagelus plebeius at the same site of this study (Farias & Rocha-Barreira 2017) and Anomalocardia brasiliana in other areas of the northeastern Brazil (Narchi 1976, Assis 1978, Barreira & Araújo 2005.…”

“…In this context, the rainy season can be considered a natural disturbance, of annual rate, with significant implications for the biology of Phacoides pectinatus. This species has a continuous reproductive cycle, as observed in sympatric bivalves Anomalocardia brasiliana and Tagelus plebeius, These species also have their gonadal development influenced mainly by the salinity variation Araújo, 2005;Farias & Rocha-Barreira, 2017). P. pectinatus population was characterized by larger animals and a spawning peak in the dry season (June to December) and by smaller animals and early gametogenesis in the rainy season (February to May).These results suggest the rainfall role on the population structure of Phacoides pectinatus.…”

“…The Phacoides pectinatus population in the Ceará river estuary presented a 1:1 sexual ratio with continuous reproduction, strongly conditioned by precipitation and salinity variations. Several tropical bivalves presented continuous reproductive cycles, such as Amusium papyraceum (Gabb, 1873) (Penchaszadeh et al 2000); Anadara ovalis (Bruguiere, 1789) (Power et al 2004); Crassostrea virginica (Cárdenas et al, 2007); Anomalocardia flexuosa (Linnaeus, 1767) (Grotta & Lunetta 1980;Barreira & Araújo 2005;Luz & Boehs 2011); and Tagelus plebeius (Lightfoot, 1786) (Farias & Rocha-Barreira 2017, Ceuta & Boehs 2012.…”

“…When the disturbance ceases, salinity returns to increase, which is a stimulating factor for spawning (Grotta & Lunetta 1980, Farias & Rocha-Barreira 2017. Under great environmental changes, many bivalves respond eliminating gametes and variations in salinity induce the animal cells to osmolality adjustments that influence bivalve reproduction (Barreira & Araújo 2005).…”

“…Definitions of the gonadal development stages were adapted from earlier studies (Assis, 1985;Darriba et al, 2004;Farias & Rocha-Barreira, 2017) (Table 1, Figures 2 and 3). The characterization of stages of gonadal development was carried out by the predominance of germ cells and by the general appearance of the gonad of each individual analyzed.…”