⚠️

HULL BIOFOULING — IMS of Concern

Found Something? STOP & REPORT to MEPA Report within 24hrs • Cease work until advised
Carpet Sea Squirt HIGH RISK
Carpet Sea Squirt
Didemnum vexillum
Sea Squirt • IMS Concern
  • Creamy/tan like old wax
  • Veiny like varicose veins
  • Leathery, NOT slimy
  • At Stirling & Henderson
Asian Green Mussel HIGH RISK
Asian Green Mussel
Perna viridis
Mussel • IMS Concern
  • Bright green shell (young)
  • Brownish-green (older)
  • Big: 80-165mm
  • NOT established in WA
European Fan Worm HIGH RISK
European Fan Worm
Sabella spallanzanii
Tube Worm • IMS Concern
  • HUGE spiral fan: 45-60mm
  • Stripy orange/purple/white
  • Brown leathery tube
  • Established — still report
Black-striped False Mussel HIGH RISK
Black-striped False Mussel
Mytilopsis sallei
Mussel • IMS Concern
  • Small: only 25mm
  • Dark stripes on shell
  • Likes brackish water
  • Check sea chests!
European Shore Crab HIGH RISK
European Shore Crab
Carcinus maenas
Crab • IMS Concern
  • Green shell
  • 5 spines each side of eyes
  • Up to 90mm across
  • NOT established in WA!
Northern Pacific Seastar HIGH RISK
Northern Pacific Seastar
Asterias amurensis
Seastar • IMS Concern
  • Large: up to 50cm
  • 5 arms, upturned tips
  • Yellow-orange body
  • Devastating if arrives!
Japanese Kelp WATCH
Japanese Kelp (Wakame)
Undaria pinnatifida
Kelp • IMS Concern
  • Big brown fronds
  • Central spine/midrib
  • Wavy ruffled edges
  • In VIC/TAS/SA — NOT WA
Killer Algae WATCH
Killer Algae
Caulerpa taxifolia
Algae • IMS Concern
  • Bright green - stands out
  • Feather-shaped fronds
  • Creeping runners
  • In NSW — NOT in WA
Asian Paddle Crab WATCH
Asian Paddle Crab
Charybdis japonica
Crab • IMS Concern
  • Paddle-shaped back legs
  • 6 spines between eyes
  • Up to 120mm across
  • Can spread disease
Large Oysters WATCH
Large Non-Native Oysters
Magallana spp.
Oyster • Hard to ID
  • Messy irregular shell
  • Sharp frilly edges!
  • Up to 400mm
  • Photo for lab ID
NZ Green-lipped Mussel WATCH
NZ Green-lipped Mussel
Perna canaliculus
Mussel • Emerging
  • Green lip on edge
  • Brown-green shell
  • MASSIVE: up to 240mm
  • Check NZ vessels
Brown Mussel WATCH
Brown Mussel
Perna perna
Mussel • Emerging
  • Dark brown/black shell
  • Up to 90mm
  • Dense thick clumps
  • From Africa/S.America
🔍 CHECK NICHE AREAS
  • Sea chests — crabs, mussels hide
  • Rope guards — crab shelter
  • Gratings — sediment accumulates
  • Rudder/prop gaps
  • Bilge keel ends
  • Anchor wells
📞 REPORT TO MEPA
  • MEPA: +94 11 2554373
  • info@mepa.gov.lk
  • MyPestGuide Reporter App
  • Report within 24 hours
  • Cease work until advised
⚠️ NOTE
  • This shows KEY species only
  • IMO Biofouling Guidelines &
  • mepa.gov.lk
  • Schedule 5, Fish Resources
  • Management Regulations 1995
Blue Mussel NATIVE
Blue Mussel ✓
Mytilus galloprovincialis
Common - No Report
  • Blue-black shell
  • NOT green
  • Pointy triangle shape
  • Normal WA 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 WA 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
HIGH RISK - Report to MEPA
WATCH - Emerging Threat
NATIVE - Normal Fouling
📞 MEPA: +94 11 2554373 • info@mepa.gov.lk
Hull Biofouling ID Guide v3.0 • WA
© 2026 MarineStream • Images: CSIRO, NIMPIS, Wikipedia