Comparison of the Salinity Range Tolerated by Teredinids (Mollusca: Teredinidae) under Controlled Conditions with that Observed in an Estuary in Papua New Guinea

Abstract

Population fluctuations seen in teredinid species settling in estuarine waters at Marshall Lagoon, Papua New Guinea, over a 3-year period were correlated with the salinlty fluctuations to which they had been subjected. From these calculations the salinity range in which the 10 most common species settled was determined. Aquaria studies were designed to test salinity tolerance ranges of these teredinids under controlled conditions by observing the effect of different salinities on the growth and survival of juveniles.

Several teredinids grew in salinities in the aquarium which were outside the range in which they were found in the estuary, and early larval development to the umbo stage in two larviparous species occurred in salinities lower than that in which adults were found in the field. From these observations it would appear that salinity tolerances of adults, and possibly presettlement larvae, are not the most important factors limiting teredinid distribution in an estuary.