We will use a mechanistic pathway modelling approach to describe New Zealand’s maritime transport network. The resulting network model will provide a realistic characterisation of movements of merchant, passenger, recreational, fishing and aquaculture vessels around New Zealand, including the offshore islands within our Exclusive Economic Zone. Utilising information on regional and environmental settings, past spreading patterns of NIS and species characteristics we will then identify the environmental and biological attributes that govern the dispersal of species via the domestic maritime network. These spatially-explicit models will be developed using the species-specific processes of introduction, establishment, and population growth at each site, similar to well-established invasive and epidemic process models. In this way, spread dynamics can be modelled as network-based flows through the real maritime network, incorporating a species’ entire life-cycle.
We will examine a range of model scenarios based on observed or hypothetical incursions of marine NIS. The network analyses applied to New Zealand’s domestic transport system under these scenarios will enable us to:
- Measure and map the potential spread patterns of marine NIS via maritime transport pathways, including geographic and seasonal influences;
- Identify important immunisation sites within the network, highlighting where maximum impact can be achieved through cost-effective intervention approaches;
- Map current and future hot spots of invasions to fast-track prevention and response efforts;
- Discover the natural barriers and structure in the NIS invasions to help adapt and coordinate regional management approaches; and
- Identify key monitoring sites within the network to maintain sustained vigilance.
The models, and the incursion and response scenarios they will be applied to, will be developed and interpreted in collaboration with the programme’s regulatory partner agencies (Northland Regional Council, Auckland Council, Marlborough District Council, Ministry for Primary Industries), Patuharakeke Te Iwi Trust and possibly other relevant end-user agencies.
The MANAGE & RESPOND research theme will support regulatory agencies and maritime industries in adopting cost-effective strategies for domestic marine pathway management – protecting environmental, economic, cultural and societal values associated with New Zealand’s coastal marine systems.