This was an expected result, as a decrease in CI is typically observed after the spawning peak in early summer (Mccrickard, 2012). Transfer of oysters from lower to higher salinities without an acclimation step could result in mortality and the NSSP guidelines (FDA, 2009) recommends that salinities in controlled purification plants not vary more than 20% from harvest water salinities. Harvest salinity during the four trials ranged from 15.8 to 29.6 psu.Thus, throughout the four trials, 58% of oysters were put into salinities outside the recommended 20% range. However, mortality in our system was less than 1% and was not affected by salinity. This contrasts with data reported from relaying studies in where oyster mortality varied from 4% (Audemard et al., 2011) to 6% (Motes and DePaola, 1996). However, the overall condition index of the oysters
decreased during depuration although it was not a function of
salinity. Lower condition indexes at the end of depuration are most
likely attributable to loss of body mass caused by lack of feeding
during 14 days.