Invading Nova Scotia: first records of Didemnum vexillum Kott, 2002 and four more non-indigenous invertebrates in 2012 and 2013

Andrea Moore,Dawn Sephton,Kevin Ma,Claudio Dibacco,Bénédikte Vercaemer

doi:10.3391/bir.2014.3.4.03

Abstract

Research and monitoring efforts led to the discovery of four new non-indigenous tunicates and one new non-indigenous anemone in Nova Scotia in 2012 and 2013. In this report, we summarize and interpret the circumstances leading up to and actions taken following the first Nova Scotian records of the high impact invasive tunicate Didemnum vexillum Kott, 2002 as well as the tunicates Styela clava Herdman, 1881, Ascidiella aspersa (Muller, 1776), and Diplosoma listerianum (Milne-Edwards, 1841) and the anemone Diadumene lineata (Verrill, 1869). While dockside research and monitoring were responsible for detections of four species, the possibility that Didemnum vexillum was present was first reported by a member of the public, through Fisheries and Oceans Canada’s Aquatic Invasive Species Monitoring program.

Highlights

Introductions and range expansions of nonindigenous marine invertebrates, especially tunicates, have caused substantial ecological impacts to fouling communities and economic impacts on bivalve aquaculture in the northeastern United States and Atlantic Canada (Blum et al 2007; Dijkstra et al 2007; Carman et al 2010; Thompson and MacNair 2004; Lutz-Collins et al 2009; McKindsey et al 2007)
The following outlines methods that led to the species discoveries, actions taken postdiscovery, the species’ current status and extent in Nova Scotia as well as implications for future monitoring
The Atlantic Canada watch list, using shipping and climate zone filters, included three tunicate species found in Nova Scotia in 2012 and 2013: Ascidiella aspersa, Diplosoma listerianum, and Didemnum vexillum

Summary

Introduction

Introductions and range expansions of nonindigenous marine invertebrates, especially tunicates, have caused substantial ecological impacts to fouling communities and economic impacts on bivalve aquaculture in the northeastern United States and Atlantic Canada (Blum et al 2007; Dijkstra et al 2007; Carman et al 2010; Thompson and MacNair 2004; Lutz-Collins et al 2009; McKindsey et al 2007). Nova Scotia was the top shipping arrival port in Atlantic Canada in 2000 and 2002 with 1215 (of 2061) and 836 (of 1225) international arrivals, respectively. Another 12 Nova Scotia ports received at least 3 visits in either of those years, including Port Hawkesbury with 80 in 2000 (Kelly 2004). Southern Nova Scotia and the Bay of Fundy are adjacent to and influenced by the prevailing oceanographic currents from the United States. They would, receive the greatest propagule pressure from established populations of non-indigenous species in eastern waters of the United States undergoing northward range expansions by natural processes

Methods

Results

Conclusion