⚠️

HULL BIOFOULING — What to Look For

Found Something Dodgy? STOP & REPORT Victoria Hull Cleaning Quick Reference — Port Phillip Bay Focus
Northern Pacific Seastar ⚠️ CONTROLLED
Northern Pacific Seastar
Asterias amurensis
CRITICAL - Established Port Phillip Bay
  • 5 arms, upturned tips
  • Yellow-orange, purple marks
  • Up to 50cm diameter
  • $1B damage to fisheries
Carpet Sea Squirt CONTROLLED
Carpet Sea Squirt
Didemnum vexillum
CONTROLLED - Sea Squirt
  • Creamy/tan like old wax
  • Veiny like varicose veins
  • Leathery, NOT slimy
  • Drips like candle wax
Asian Green Mussel CONTROLLED
Asian Green Mussel
Perna viridis
CONTROLLED - Mussel
  • Bright green shell (young)
  • Brownish-green (older)
  • Big: 80-165mm
  • Blue-green inside
European Fan Worm ESTABLISHED
European Fan Worm
Sabella spallanzanii
ESTABLISHED - Port Phillip
  • HUGE spiral fan: 45-60mm
  • Stripy orange/purple/white
  • Brown leathery tube
  • Report outside PPB!
Black-striped False Mussel CONTROLLED
Black-striped False Mussel
Mytilopsis sallei
CONTROLLED - Mussel
  • Small: only 25mm
  • Dark stripes on shell
  • Likes brackish water
  • Check sea chests!
Japanese Kelp ESTABLISHED
Japanese Kelp (Wakame)
Undaria pinnatifida
ESTABLISHED - Don't Spread!
  • Big brown fronds
  • Central spine/midrib
  • Wavy ruffled edges
  • Up to 3m long
Asian Date Mussel ESTABLISHED
Asian Date Mussel
Arcuatula senhousia
ESTABLISHED - Don't Spread
  • Small: up to 30mm
  • Thin fragile shell
  • Greenish with zigzags
  • Forms dense mats
Killer Algae CONTROLLED
Killer Algae
Caulerpa taxifolia
CONTROLLED - Algae
  • Bright green - stands out
  • Feather-shaped fronds
  • Creeping runners
  • Up to 65cm tall
Stalked Sea Squirt WATCH
Stalked Sea Squirt
Styela clava
WATCH - Sea Squirt
  • Brown pickle on a stalk
  • Leathery & wrinkly
  • 50-160mm tall
  • Stands alone
Pacific Oyster WATCH
Pacific Oyster
Magallana gigas
ESTABLISHED - Oyster
  • Messy irregular shell
  • Sharp frilly edges!
  • Up to 400mm
  • Glued flat to surface
NZ Green-lipped Mussel WATCH
NZ Green-lipped Mussel
Perna canaliculus
CONTROLLED - Mussel
  • Green lip on edge
  • Brown-green shell
  • MASSIVE: up to 240mm
  • Check NZ vessels
Vase Tunicate WATCH
Vase Tunicate
Ciona intestinalis
WATCH - Sea Squirt
  • See-through yellow-green
  • Tube/vase shape
  • Two holes on top
  • Soft & squishy
Pleated Sea Squirt WATCH
Pleated Sea Squirt
Styela plicata
WATCH - Sea Squirt
  • Ridged like a brain
  • Grey-brown colour
  • Golf ball size: 70mm
  • Sits alone
European Shore Crab ESTABLISHED
European Shore Crab
Carcinus maenas
ESTABLISHED - VIC
  • Green shell
  • 5 spines each side of eyes
  • Up to 90mm across
  • Hides in sea chests
Asian Paddle Crab WATCH
Asian Paddle Crab
Charybdis japonica
CONTROLLED - Niche Hitchhiker
  • Paddle-shaped back legs
  • 6 spines between eyes
  • Up to 120mm across
  • Olive-brown colour
Blue Mussel NATIVE
Blue Mussel ✓
Mytilus galloprovincialis
Common - No Report
  • Blue-black shell
  • NOT green
  • Pointy triangle shape
  • Normal VIC fouling
Native Tube Worms NATIVE
Native Tube Worms ✓
Serpulidae
Common - No Report
  • SMALL fan (not 45-60mm)
  • White hard tubes
  • NOT brown leathery tube
  • Normal VIC 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
CONTROLLED - Established Pest
CONTROLLED - Report to Agriculture VIC
WATCH - Report 24hrs
NATIVE - Normal
📞 Found Something? STOP CLEANING — Call Agriculture VIC: 136 186
Hull Biofouling ID Guide v3.0
Victoria • Print A3 Landscape