⚠️

HULL BIOFOULING — What to Look For

Found Something Dodgy? STOP & REPORT Northern Territory Hull Cleaning — Darwin 1999 Eradication Success
Black-striped False Mussel ⚠️ CLASS A/B
Black-striped False Mussel
Mytilopsis sallei
CLASS A/B - Eradicated 1999
  • Small: only 25mm
  • Dark stripes on shell
  • $2.2M eradication cost
  • Check sea chests!
Asian Green Mussel ⚠️ CLASS A/B
Asian Green Mussel
Perna viridis
CLASS A/B - Tropical Threat
  • Bright green shell (young)
  • Brownish-green (older)
  • Big: 80-165mm
  • Tropical Asia origin
Asian Paddle Crab ⚠️ CLASS A/B
Asian Paddle Crab
Charybdis japonica
CLASS A/B - White Spot Risk!
  • Paddle-shaped back legs
  • 6 spines between eyes
  • Carries White Spot Virus!
  • Barramundi threat
Carpet Sea Squirt CLASS A/B
Carpet Sea Squirt
Didemnum vexillum
CLASS A/B - Sea Squirt
  • Creamy/tan like old wax
  • Veiny like varicose veins
  • Leathery, NOT slimy
  • Drips like candle wax
Charru Mussel CLASS A/B
Charru Mussel
Mytella strigata
CLASS A/B - Not in AUS
  • Medium: 22-50mm
  • Variable exterior colours
  • Blue-purple interior — key ID
  • Yellowish flesh
Killer Algae NATIVE
Caulerpa (Native)
Caulerpa taxifolia
NATIVE - Not a pest in NT
  • Bright green feathery algae
  • Native to northern Australia
  • Not on NT declared weeds list
  • Not a biosecurity concern here
European Fan Worm CLASS A/B
European Fan Worm
Sabella spallanzanii
CLASS A/B - Tube Worm
  • HUGE spiral fan: 45-60mm
  • Stripy orange/purple
  • Brown leathery tube
  • Fan pulls in when close
Northern Pacific Seastar WON'T PERSIST
Northern Pacific Seastar
Asterias amurensis
Cold-water — won't survive in NT
  • 5 arms, upturned tips
  • Yellow-orange colour
  • Up to 50cm diameter
  • Know it — transiting vessels
Stalked Sea Squirt WATCH
Stalked Sea Squirt
Styela clava
CLASS A/B - Sea Squirt
  • Brown pickle on stalk
  • Leathery & wrinkly
  • 50-160mm tall
  • Stands alone
Black Scar Oyster PRESENT
Black Scar Oyster
Magallana bilineata
Present in one NT marina
  • Large: up to 212mm
  • Dark scar on BOTH valves
  • Yellow-purple shell
  • Report new locations!
NZ Green-lipped Mussel WATCH
NZ Green-lipped Mussel
Perna canaliculus
WATCH - Mussel
  • Green lip on edge
  • MASSIVE: up to 240mm
  • Brown-green shell
  • Check NZ vessels
Vase Tunicate WATCH
Vase Tunicate
Ciona intestinalis
CLASS A/B - Sea Squirt
  • See-through yellow-green
  • Tube/vase shape
  • Two holes on top
  • Soft & squishy
Brown Mussel CLASS A/B
Brown Mussel
Perna perna
CLASS A/B - Not in AUS
  • Large brown mussel
  • Up to 120mm
  • From Africa/S. America
  • NOT in Australia
Chinese Mitten Crab CLASS A/B
Chinese Mitten Crab
Eriocheir sinensis
CLASS A/B - Crab
  • Hairy "mittens" on claws
  • White-tipped claws
  • Up to 80mm carapace
  • NOT in Australia
Asian Date Mussel WATCH
Asian Date Mussel
Arcuatula senhousia
CLASS A/B - Mussel
  • Small: up to 30mm
  • Thin fragile shell
  • Greenish zigzags
  • Forms dense mats
Blue Mussel NATIVE
Blue Mussel ✓
Mytilus galloprovincialis
Common - No Report
  • Blue-black shell
  • NOT green
  • Pointy triangle
  • Normal NT fouling
Native Tube Worms NATIVE
Native Tube Worms ✓
Serpulidae
Common - No Report
  • SMALL fan
  • White hard tubes
  • NOT brown leathery
  • Normal NT fouling
Native Sea Squirts NATIVE
Native Sea Squirts ✓
Didemnidae
Compare Carefully!
  • Thin jelly-like mat
  • NOT veiny/waxy
  • Slimy, not leathery
  • If unsure - REPORT IT
MarineStream
CLASS A/B - Declared Pest
CLASS A/B - Report to NT Fisheries
WATCH - Report 24hrs
NATIVE
📞 Found Something? STOP CLEANING — Call NT Fishwatch: 1800 891 136
Hull Biofouling ID Guide v3.0
Northern Territory • Print A3 Landscape
Black Scar Oyster photo: NIMPIS