Ministry for Primary Industries

Sea Spurge Population Analysis and Ocean Modelling for Surveillance Prioritisation

Sea spurge (Euphorbia paralias) is a highly invasive coastal weed that poses a serious threat to the ecological and physical structure of New Zealand coastal habitats. Its seeds can survive for up to 6 years in sea water and can float across the Tasman Sea, from Australia to New Zealand, before germinating. In New Zealand sea spurge can produce up to 5,000 seeds per plant from 4-6 months of age, and once established could form dense monocultures of up to 150,000 plants per hectare anywhere its roots can get a hold, including coastal pastureland.
Early detection through effective surveillance is key to controlling sea spurge, however resourcing surveillance for New Zealand’s ~ 15,000 km coastline on a regular basis is not feasible. We need to be able to prioritise areas for surveillance, and require an understanding of which coastal areas are most likely to have sea spurge arrive and establish.
This project aim is to carry out the research required to identify areas at high risk of sea spurge arrival and establishment along the New Zealand coast. This will be delivered by using hydrodynamic dispersal modelling, investigation of the genetic relatedness and gene flow between known sea spurge populations and sea spurge climate suitability.

Department/Business Unit: New Zealand Food Safety