As the name suggests, the Derwent River sea star (Marginaster littoralis) occupies five locations throughout Tasmania’s Derwent River, none of which fall within the boundary of nature reserves.
Although little is known about the life cycle of
Marginaster littoralis, characteristics of a similar sea star (Patiriella vivipara) suggest that the species has a life span of around four years.
Five known subpopulations are all geographically isolated from one another, albeit within the tight confines of the Derwent River.
Insufficient data exists on the current area of occupancy of the Derwent River Seastar, but it is unlikely to exceed 0.01 km2
There is insufficient data to indicate the species’ total population size. None of the published accounts of the species provide estimates of abundance. But data indicates that this little asteroid is likely to be extinct.
The destruction of the species’ habitat is a further threat. Populations in the Derwent River are located close to Hobart, and are subject to run-off pollution, but sadly, there is no recovery plan in place to protect the species.
- Photo: In order by Blair Patullo and A J Dartnall
THIS TINY SEA STAR IS THE FIRST MARINE EXTINCTION DOCUMENTED IN AUSTRALIA
Scientists only knew the
Derwent River sea star
for about 25 years. It was first described in 1969, but scientists noticed a decrease in its population in the early 90’s. Field surveys conducted in 1993 and 2010 failed to find a single individual.
The Derwent River sea star was listed as critically endangered by the governments of Tasmania and Australia. But now, according to a new scientific publication on the state population, is
is now extinct. Is the first documented extinction of an Australian marine animal, and one of the few documented recent marine invertebrate extinctions.
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