Recruitment patterns and population development of the invasive ascidian Ciona intestinalis in Prince Edward Island, Canada

Abstract

In 2004, an exotic tunicate, Ciona intestinalis, was detected in Montague River, Prince Edward Island. Since it was first detected, this exotic species has become an invasive nuisance species creating production problems in bivalve aquaculture industries including handling difficulties and resource competition with the cultured blue mussel, Mytilus edulis. Ciona intestinalis has become a challenging species to manage because of its long reproductive period and rapid biomass accumulation. Population development of C. intestinalis in a single season was investigated to inform the aquaculture management of this fouling species. The study focused on seasonal recruitment patterns and the subsequent development of the C. intestinalis population after settlement. Recruitment on experimental collectors occurred from mid-June until late November, with a peak in late August. A rapid increase in biomass was documented in late July, six weeks after the initial recruitment. No substantial increase in C. intestinalis biomass was observed in new recruits after mid-August.