Resistance of larvae of common species of White Sea invertebrates to extreme changes in salinity

This study examines the effect of sharp changes in salinity on pelagic larvae of ten common species of invertebrates from the brackish White Sea (Mollusca, Polychaeta, Echinodermata, Cnidaria, Ascidia). For five species, the low salinity resistance limit was in the range of 8–12‰: for the gastropod Littorina littorea, it was below 8‰; for Dyaphana sp. and the bivalves Hiatella arctica and Heteranomia ovata, it was more than 12‰; and for the ascidian Styela rustica, it was 16‰. About 50% of larvae of four investigated species were able to withstand high salinity and survived at 36–40 and even 50‰ (Littorina). Larvae of littoral-sublittoral species proved to be more euryhaline than larvae of sublittoral species.