The Asian kelp Undaria pinnatifida (Laminariales, Phaeophyceae) was first recorded in New Zealand in 1987 and has since spread via shipping traffic and other vectors to a number of ports and harbours. Here we report the results of laboratory and field studies devised to assess the potential for natural dispersal of Undaria from a founding population. Under laboratory conditions, > 90% of Undaria spores were viable in seawater for at least 5 days, with some viable after 14 days. Spores artificially released into a tidal current resulted later in sporophytes appearing on artificial surfaces positioned 10 m down-current of the release point. Field monitoring of a founding population within the Marlborough Sounds, New Zealand, suggested that natural populations spread at least 100 m yr⁻¹. Reasons for the differences between the dispersal distances of the artificially released spores (10 m) and natural populations (100 m) are discussed. We propose that spore dispersal from fixed stands of Undaria results primarily in short-range spread (metres to hundreds of metres), with dispersal of fragments or whole sporophytes facilitating spread at scales of hundreds of metres to kilometres.

Item Type:	Refereed Article
Keywords:	invasive seaweed, Undaria, dispersal
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:	Environmental Management
Objective Group:	Coastal and estuarine systems and management
Objective Field:	Control of pests, diseases and exotic species in coastal and estuarine environments
UTAS Author:	Hurd, CL (Professor Catriona Hurd)
ID Code:	93139
Year Published:	2000
Web of Science® Times Cited:	69
Deposited By:	IMAS Research and Education Centre
Deposited On:	2014-07-14
Last Modified:	2014-08-04
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