eCite Digital Repository

Hotspots of exotic free-spawning sex: man-made environment facilitates success of an invasive seastar


Ling, SD and Johnson, CR and Mundy, CN and Morris, A and Ross, DJ, Hotspots of exotic free-spawning sex: man-made environment facilitates success of an invasive seastar, Journal of Applied Ecology, 49, (3) pp. 733-741. ISSN 0021-8901 (2012) [Refereed Article]

Restricted - Request a copy

Copyright Statement

Copyright 2012 The Authors

DOI: doi:10.1111/j.1365-2664.2012.02133.x


1. The introduction of exotic species to new areas poses a major threat to the environment. For those introduced species that establish and survive beyond the short term, the opportunities to manage the risk of continuing spread often rest with limiting reproductive output. The introduced northern Pacific seastar Asterias amurensis is an ecologically important pest that has established in the Derwent Estuary (Australia). Driven by oversupply of bivalve prey, it is persistent, abundant and fecund when associated with man-made structures such as docks, marinas, jetties and piers, that is, ‘wharves’.

2. As a free-spawning invertebrate, fertilization by A. amurensis is a critical life-history stage constrained by strong Allee effects. Eggs must be released in close proximity to sperm sources because the chances of achieving fertilization drastically reduce with increasing distances of spawner separation.

3. Investigation of zygote production in the Derwent Estuary using a spatially explicit model of free-spawning fertilization shows that A. amurensis at wharves, while representing < 10% of the total population in the estuary and concentrated in < 0.1% of the total area, may contribute > 90% of total zygote production. Given the seastars’ long-lived and highly dispersive larvae, we show that wharves not only represent important sites of invasion but also facilitate propagule pressure promoting secondary invasions.

4.Synthesis and applications. In the absence of effective pest control solutions, focusing on reproductive hotspots has the potential to reduce further spread of established marine pests and to alleviate ongoing ecological impacts. In the case of the northern Pacific seastar, elimination of highly localized wharf populations annually prior to spawning can reduce overall zygote production by up to estimated ~90%. The long-term protection of key sources of larval production is a common goal for marine reserve design and fisheries management. However, the same concept but in reverse, whereby larval production is minimized at key sources, could be effective in the management of introduced pests in subtidal marine environments.

Item Details

Item Type:Refereed Article
Keywords:Allee effect, anthropogenic habitat, artificial habitat, Asterias amurensis, coastal infrastructure, ecological restoration, fertilization modelling, free-spawning ecology, introduced marine pest, pest management
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Control of pests, diseases and exotic species in marine environments
UTAS Author:Ling, SD (Dr Scott Ling)
UTAS Author:Johnson, CR (Professor Craig Johnson)
UTAS Author:Mundy, CN (Dr Craig Mundy)
UTAS Author:Ross, DJ (Associate Professor Jeff Ross)
ID Code:78215
Year Published:2012
Web of Science® Times Cited:14
Deposited By:IMAS Research and Education Centre
Deposited On:2012-06-18
Last Modified:2017-10-31
Downloads:6 View Download Statistics

Repository Staff Only: item control page