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 Northern
Pacific sea star
Asterias amurensis
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Overview
The
northern Pacific sea star is currently found in huge
numbers in southern parts of Australia. If it comes
to New Zealand, it could have a serious impact on our
shellfish farming industry and our marine environment
generally.
The
northern Pacific sea star feeds on wild and farmed shellfish
and a wide variety of other marine animals. It is normally
found in shallow water but can be found as deep as 200
metres. It prefers muddy, sandy, or pebbly surfaces.
You would not normally see it on reefs or in areas with
large waves.
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How could it get here?
The
larvae of northern Pacific sea stars could reach New
Zealand in ballast water. The spawning adults could
arrive in a ship's containers for carrying equipment
and fish. Juveniles could attach themselves to the outside
of a ship or boat's hull.
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Description
Size:
Up to 46 cm across.
Colour:
Varies from yellow to purple/red.
Topside:
Arms covered with numerous unevenly arranged small spines
with jagged ends.
Underside:
On each arm, the spines are in a single line along the
groove where tube feet lie, joining at the mouth in
a fan shape.
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Key
features
Northern
Pacific seastars have five arms, which have pointed
and often up-turned tips. The arms join onto a central
disc and have clumps of small chisel-like spines along
each side.
For
more information, see:
Northern
Pacific seastar action plan September 2001 (PDF
392KB) - Link to NZ Biodiversity web site.
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 Chinese
mitten crab
Eriocheir sinensis
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Overview
If
the Chinese mitten crab entered New Zealand waters,
it could pose a serious threat to both our marine biological
communities and the stability of our river banks. This
crab is native to the rivers and estuaries of China
and Korea along the Yellow Sea.
The
young crabs grow and develop in fresh water. The adult
crabs migrate to the sea, where they reproduce and die.
The
crabs burrow into river banks and can cause accelerated
erosion and slumping. They have been known to block
water intakes in irrigation and water-supply schemes.
They also carry a lung parasite that infects people.
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How could it get here?
Chinese
mitten crabs could arrive in New Zealand as young animals
in a ship's ballast water or as adults in a ship's containers
for carrying equipment and fish.
These
crabs are also a food source in some cultures and so
might be introduced deliberately.
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Description
Size:
Adult up to 80 mm wide, juvenile up to 20-25 mm wide.
Colour:
Light brown.
Body
shape: Smooth and rounded.
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Key features
The
front claws of the crabs are large and hairy with white
tips.
Their
legs are twice as long as the width of their body and
they have a notch between the eyes.
For
more information, see:
Chinese
mitten crab action plan September 2001 (PDF 356KB)
- Link to NZ Biodiversity web site.
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