Spatial and temporal spatfall of the winged Pearl Oyster Pteria sterna (Gould, 1851), in Equatorial Coasts

The aim of the present study was to determine the spatial and temporal spatfall of the winged pearl oyster Pteria sterna in three different synthetic collectors (green mesh bags + mesh fence and mosquito net), deployed at three depths (2, 4 and 6 m). Samples from the bags were obtained over a period of 45 days, while environmental variables including chlorophyll a (Chl-a), oxygen, total particulate matter (TPM) and organic fraction (POM), salinity and temperature were measured each 3-week period. The study was conducted between November 2016 and October 2017 at El Palmar, Santa Elena Peninsula, Ecuador. Results showed significant differences in the spatial and temporal spatfall of the winged pearl oyster, with higher spatfall during November to early December 2016, followed by lower spat availability from later December to March 2017. A further increment of spatfall was observed from May–June and intensified for the last period of June–July 2017. The number of spat decreased during the following August–September and September–October periods. An ANOVA II analysis showed higher significant differences between deployment depths of collectors and the type of collector, as well as their interaction. Furthermore, Principal components analysis only showed a significant and negative relationship between spatfall and temperature, although results suggest that Chl-a may be a trigger that could induce oyster spawning events. Based on these results, possible strategies to improve the collection of the spat of winged pearl oyster P. sterna on the Ecuadorian coastline are discussed.