No abstract

This study assessed the effect of salinity on embryonic development, larval growth and survival of the yellow clam Mesodesma mactroides in laboratory. Embryos and larvae of M. mactroides were submitted and maintained at four different salinities: 20, 25, 30 and 35 ppt, to determine optimal conditions for the species. Through descriptive analysis, the results showed that the embryos tolerate salinities between 25 -35 ppt, presenting fast metamorphoses at salinities 30 and 35 ppt, during experimental period of 27 hours. The same tolerance pattern was observed in larval stage (25 -35 ppt), showing a better development in salinity of 35 ppt. This result is verifi ed in biometric analyzes of height and length of the shells and survival rate, with higher averages in treatments with salinity 35 ppt. The experimental period of this stage lasted 27 days, when the larvae were able to settle. These results indicate that embryos and larvae of M. mactroides tolerate salinities between (25-35 ppt), with the best growth and survival on high salinities being recommended to better yields in laboratory.

The species Amarilladesma mactroides (= Mesodesma mactroides) (Reeve, 1854) is a sand bivalve, popularly known as yellow clam, with socioeconomic importance in regions where it is endemic (Herrmann et al., 2011;Santos et al., 2016;McLachlan, 2018). The species has been the subject of research for decades regarding its habitat (Coscarón, 1959), reproductive cycles in its natural environment (Herrmann et al., 2009), population dynamics (Bergonci & Thomé, 2008) and the reduction in natural stocks and outbreaks of mortalities that affect the species in areas of its distribution (Carvalho et al.,