Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Second record of Diplosoma listerianum (Milne-Edwards, 1841) five years after and 280 kilometres from the site of the first record in Nova Scotia.

Abstract

Five samples of Diplosoma listerianum, a non-indigenous colonial ascidian species complex, were collected via SCUBA between August 27 and September 28, 2017, from four sites in the coastal waters (depth ranging between 3.1 and 18.0 metres) around Brier Island, Nova Scotia, Canada. These samples constitute the second record of D. listerianum in Nova Scotia-five years after the first discovery and 280 kilometres (by sea) from the site of the first record. Semi-quantitative abundance of D. listerianum from Brier Island was determined and was found to be frequent or common in three of these four sites that were surveyed via SCUBA. The occurrence at several sites, coupled by the presence of eggs, ovaries, and larvae in some tissue samples suggest that there is presently an established population of D. listerianum off of Brier Island.