Asparagopsis taxiformis is a marine alga that poses a genuine threat to New Zealand's coastal ecosystems. Identifying it accurately matters, because it bears a close resemblance to the native Asparagopsis armata, and the two are easily confused.
The distinction comes down to a single structural feature: the branching pattern. Asparagopsis armata, the native species, has distinctive harpoon-like hooks on its side branches. The invasive Asparagopsis taxiformis has none. The invasive alga spreads both through natural dispersal and by travelling on underwater equipment, and once it takes hold it can smother and displace native species, with real consequences for local ecosystems.
Learning to spot this difference is the most practical step anyone can take toward protecting those ecosystems. When you encounter an alga underwater, examine the side branches closely. Harpoon-like hooks point to the native Asparagopsis armata. If those hooks are missing, the alga may well be the invasive Asparagopsis taxiformis.
