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HULL BIOFOULING — What to Look For

📍 NEW SOUTH WALES
Found Something Dodgy? STOP & REPORT NSW Hull Cleaning Quick Reference
Carpet Sea Squirt PROHIBITED
Carpet Sea Squirt
Didemnum vexillum
OUTBREAK - Sydney Harbour 2023
  • Creamy/tan waxy, veiny texture
  • Leathery, NOT slimy
  • Can thicken to 10cm
  • Tendrils up to 1m long
Northern Pacific Seastar PROHIBITED
Northern Pacific Seastar
Asterias amurensis
Prohibited in NSW
  • Large - up to 50cm diameter
  • 5 arms with upturned tips
  • Yellow-orange with purple marks
  • Undersides completely yellow
Asian Green Mussel PROHIBITED
Asian Green Mussel
Perna viridis
APMPL Listed
  • Bright green shell (young)
  • Big: 80-165mm
  • Blue-green iridescent inside
  • Check sea chests!
Black-striped False Mussel PROHIBITED
Black-striped False Mussel
Mytilopsis sallei
APMPL Listed
  • Small: 20-25mm only
  • Dark radiating stripes
  • Prefers brackish water
  • Darwin cost $2.2M to eradicate
Asian Paddle Crab PROHIBITED
Asian Paddle Crab
Charybdis japonica
Prohibited in NSW
  • Paddle-shaped rear legs
  • 6 spines either side of eyes
  • Up to 120mm carapace
  • Carries White Spot Virus!
Asian Date Mussel PROHIBITED
Asian Date/Bag Mussel
Arcuatula senhousia
Prohibited in NSW
  • Small: up to 30mm
  • Thin, fragile shell
  • Zigzag markings
  • Forms dense mats (1000s/m²)
Charru Mussel PROHIBITED
Charru Mussel
Mytella strigata
APMPL Listed 2020
  • 22-50mm, variable colours
  • Zigzags, spots, or bands
  • Blue-purple opalescent inside
  • Yellowish flesh
Chinese Mitten Crab PROHIBITED
Chinese Mitten Crab
Eriocheir sinensis
Prohibited
  • Dense hair "mittens" on claws
  • White-tipped claws
  • Up to 80mm carapace
  • 4 spines each side of eyes
NZ Green-lipped Mussel WATCH
NZ Green-lipped Mussel
Perna canaliculus
Watch Species
  • Green lip on shell edge
  • MASSIVE: up to 240mm
  • Dark brown to green shell
  • Check vessels from NZ
Japanese Kelp WATCH
Japanese Kelp (Wakame)
Undaria pinnatifida
APMPL - Watch for NSW
  • 1-3m long brown fronds
  • Central midrib full length
  • Wavy ruffled edges
  • Frilly sporophyll at base
Stalked Sea Squirt WATCH
Stalked Sea Squirt
Styela clava
Watch Species
  • Brown pickle on a stalk
  • Leathery, wrinkled texture
  • 50-160mm tall
  • Stands alone
Vase Tunicate WATCH
Vase Tunicate
Ciona intestinalis
Watch Species
  • Translucent yellow-green
  • Tube/vase shaped
  • Two siphons at top
  • Soft and squishy
Caulerpa CLASS 1
Caulerpa (Killer Algae)
Caulerpa taxifolia
NOXIOUS - 14+ NSW estuaries
  • Bright green feathery fronds
  • Up to 30cm in NSW
  • Creeping stolons/runners
  • Sydney Hbr, Pittwater, etc.
European Shore Crab EST
European Shore Crab
Carcinus maenas
Notifiable - Southern NSW
  • Green shell, 50-90mm
  • 3 blunt spines on rostrum
  • 5 spines each side of eyes
  • NO swimming paddles
European Fan Worm EST
European Fan Worm
Sabella spallanzanii
Established - Eden, Botany Bay
  • Spiral fan crown 45-150mm
  • Banded orange/purple/white
  • Brown leathery tube
  • Body up to 400mm
Pacific Oyster EST
Pacific Oyster
Magallana gigas
Movement Controls Apply
  • Large up to 400mm
  • Irregular, frilly sharp edges
  • Grey-white to purple
  • Competes with Sydney Rock
Blue Mussel NATIVE
Blue Mussel ✓
Mytilus galloprovincialis
Common - No Report
  • Blue-black shell
  • 50-100mm, triangular
  • NOT green
  • Normal NSW fouling
Sydney Rock Oyster NATIVE
Sydney Rock Oyster ✓
Saccostrea glomerata
Native NSW Oyster
  • Rounder, smaller <80mm
  • Less frilly than Pacific
  • Native to NSW
  • Normal NSW fouling
PROHIBITED - Stop & Report
WATCH - Report 24hrs
ESTABLISHED - Prevent Spread
NATIVE
📞 Found Something? STOP CLEANING — NSW DPI: 1800 675 888
Hull Biofouling ID Guide v3.0 NSW
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