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Establishment of the Long-Spined Sea Urchin Centrostephanus rodgersii in Tasmania: First Assessment of Potential Threats to Fisheries
Citation
Johnson, CR and Ling, SD and Ross, DJ and Shepherd, S and Miller, KJ, Establishment of the Long-Spined Sea Urchin Centrostephanus rodgersii in Tasmania: First Assessment of Potential Threats to Fisheries, Fisheries Research and Development Corporation, FRDC Project No 2005 (2005) [Contract Report]
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Abstract
The pattern of distribution of the long-spined sea urchin Centrostephanus rodgersii over
ca. 40 y in the Kent group, Bass St., suggests initial establishment in the mid 1960s with
subsequent expansion of populations to its current status as the dominant invertebrate on
shallow subtidal rocky reef. On the east coast of Tasmania, C. rodgersii is most abundant
in the vicinity of its location of initial discovery in 1978, but it occurs throughout the east
coast between Eddystone Pt in the north and Recherche Bay in the south. Barrens habitat,
supporting high densities of sea urchins but largely devoid of macroalgae, occurs
extensively in the Kent group and at several sites on the northern half of the Tasmanian
east coast, but declines with increasing latitude and does not occur south of the Tasman
Peninsula. At the southern extent of barrens habitat on the open coast, barrens are
incipient and occur as small patches in macroalgal beds. Evidence suggests that the
barrens habitat in the Kent group and on the open rocky coast of Tasmania is formed by
grazing of C. rodgersii and not by Heliociaris erythrogramma, another sea urchin that
occurs on these barrens. This is largely because there is a significant positive relationship
between C. rodgersii density and extent of barrens but not between H. erythrogramma
density and extent of barrens, and because H. erythrogramma is not know to form barrens
on exposed coast. These collective patterns suggest that the incursion of C. rodgersii into
Tasmanian waters was from the north, and that spread on the east coast of Tasmania
propagated from an ‘epicentre’ in the vicinity of St Helens in the northeast. We suggest
that the initial incursion was via larvae transported from NSW in the East Australian
Current, which has increasingly influenced the east coast of Tasmania over at least the
past 4-5 decades. The lack of any genetic differentiation among C. rodgersii populations
in NSW, the Kent group and the east coast of Tasmania is consistent with this view.
Item Details
Item Type: | Contract Report |
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Keywords: | Long-spined sea urchin, Centrostephanus rodgersii, urchin barrens, lobster, abalone |
Research Division: | Biological Sciences |
Research Group: | Ecology |
Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Understanding climate change |
Objective Field: | Effects of climate change on Australia (excl. social impacts) |
UTAS Author: | Johnson, CR (Professor Craig Johnson) |
UTAS Author: | Ling, SD (Dr Scott Ling) |
UTAS Author: | Ross, DJ (Associate Professor Jeff Ross) |
UTAS Author: | Miller, KJ (Dr Karen Miller) |
ID Code: | 80089 |
Year Published: | 2005 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2012-10-22 |
Last Modified: | 2012-10-23 |
Downloads: | 3 View Download Statistics |
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