A fast grower that forms dense colonies on any hard surface - including your boat, shells, reefs, wharf piles, aquaculture structures and mooring lines. Wakame crowds out native species and steals their light and space. This could mean our favourite dive spots are never to be the same again.

How to identify this species:

• Golden to dark brown 

• Slimy to touch

• Distinct mid-rib (if plant >5cm)

• Eroded top on blade of adults

• Mature plants have filled reproductive structure at base of plant

• Juveniles appear as single leaf

Photos / Northland Regional Council and others