Effect of suspended inorganic matter on fertilization success, embryonic development, larval settlement, and juvenile survival of the vase tunicate Ciona intestinalis (Linnaeus, 1767)

Prince Edward Island (PEI), Canada, has seen the introduction and the establishment of many exotic tunicate species since the late 1990’s. Exploratory research in the Orwell Bay identified turbidity as a potential factor in this failure of tunicates, and in particular Ciona intestinalis, to establish despite multiple unintentional introductions. Laboratory experiments showed significant negative effect of increased suspended inorganic matter on the fertilization success, larval settlement, and the survival of juvenile tunicates. Although the levels of turbidity tested (up to 22 and 32 NTU) reduced all of these processes it did not completely eliminate them. High levels of turbidity have the potential to prevent establishment of non-native tunicates in some locations where establishment would otherwise be expected.