Ocorrência de larvas Pedivéliger de ostras do genero Crassostrea Sacco, 1897 no setor euhalino do Complexo Estuarino de Paranaguá – PR.

Spatio-temporal Distribution Pattern of Oyster Larvae in Guaratuba Bay, Paraná State - Brazil

“…The high larval concentrations in the bay's inner sector makes a large number of larvae return for settling in natural oyster banks purposes. Similar behavior was observed by [26,5] in oyster larvae found in the Paranaguá Estuarine Complex. In addition, the conspicuous bedding attributed to the bay's geomorphologywhich presents a narrow and deep channel at its entrance and a shallow inner region -and to its water -residence time can contribute to larvae retention in the bay's internal sections.…”

“…All these stages are influenced by endogenous and exogenous factors, such as temperature, food availability and salinity, which are the ones mostly influencing gonadal maturation and larval cycle duration [18,9]. Based on results in the present study, there are larvae in plankton throughout the year; however, this pattern is strongly influenced by temperature, since the highest larval density was observed under high temperatures and gonadal maturation [19,5]. The species C. rhizophorae and C. brasiliana (sin= C. gasar) recorded and 24-day pelagic larval duration under controlled laboratory conditions, respectively, instead of larval periods (at 27°C) [20].…”

“…Studies conducted with C. rhizophorae and C. brasiliana in several coastal areas in Northeastern, Southeastern and Southern Brazil have suggested oyster reproduction all year long; spawning takes place in the hottest times of the year [22,23,24,5]. Food availability and salinity can also affect gametogenesis, as well as larval duration and distribution in the plankton [25].…”

“…Larval-period duration in natural environments is mainly determined by water temperature and food availability [3]. However, factors such as salinity and water turbidity can affect larval dispersion [4,5]. Although larvae are able to horizontally and vertically move in the water column, aspects such as currents and tidal speed enable wider larval dispersion, mainly in horizontal position [6,7].…”

“…Complex interactions between the larval swimming and the circulation characteristics of the environment have been suggested as retention mechanisms [9], while other studies suggest that the larvae can maintain their position in the estuary, regardless of environmental factors [12]. Oyster larvae are most abundant near the surface of the water during their early stages of development, but they move closer to the bottom when they reach the end of their pelagic stage, theoretically because they are looking for a substrate for fixation [5]. Some studies have also addressed the influence of luminosity on the distribution of oyster larvae [13].…”