Pathogen and virus trajectories

Simulating surface pathogen movement

Pathogens, viruses or pollutants can appear in the marine environment. Estimating their trajectories of movement is important to assist mitigation of any threat they pose to the oceanic ecosystems, fisheries and aquaculture.

The following 3 case studies simulate surface pathogen movement using the Two Gulfs Model (TGM) results off:

  1. Boston Bay Island
  2. northern Kangaroo Island
  3. Wallaroo.

In each case 9 adjacent surface cells are seeded with "floats" into these regions starting May 21st 2017 and tracked for 4 days. In all animations below, surface currents and temperature are indicated.

Outer Boston Bay simulation

Over the 4 days of the simulation, the floats moved off shore approximately 10 km but still remained relatively tightly clustered. Note that the cluster moved significantly to the south before moving back north to be located at approximately the same latitude as the original seeding.

View the Boston Bay simulation (MP4 3.0 MB)

Stokes Bay, Kangaroo Island simulation

A cluster of 9 floats, released just north of Stokes Bay on Kangaroo Island during the same May period above, are displaced over 30 km to the east by the prevailing currents. The floats remain tightly clustered over the 4 days with short retrograde motions during the peak tides.

View the Stokes Bay simulation (MP4 2.5 MB)

Wallaroo simulation

In the last example the nine floats are released just to the west of Wallaroo during the May simulation. In this case the displacements are about 10 km to the south but the floats do not remain as tightly clustered after the first two days. The floats enter a strongly sheared boundary current and are dispersed considerably. This would indicate a much greater uncertainty about the position of anything placed in the water at the initial location of the floats.

View the Wallaroo simulation (MP4 3.7 MB)

Search and rescue applications

The now-cast/forecast system examples can be applied to search and rescue of lost vessels and people.

Dispersion of oil or larvae

The 3 simulated surface pathogen movement examples adopt buoyant floats that remain at the surface. It is relatively easy to allow the floats to simulate the dispersion and trajectories of movement due to more complicated buoyancies such as that of oil and/or prawn larvae.

Mass fish mortalities

Model simulations can be run backwards in time to determine if likely common origins exist of buoyant matter including that which arises from mass mortality fish outbreaks.


This is a research and experimental product and no liability is assumed for the use of the eSA-Marine system or its products including now-casts and forecasts. In particular, this includes all conditions outlined in the general PIRSA disclaimer that can be accessed here or at the bottom of this page. Moreover, other sources of ocean now-cast/forecasts and or data may not align or be consistent with output from the eSA-Marine System which may be in error and/or out of date. Users should obtain their own independent advice. No liability is assumed for the eSA-Marine products presented here.

Page Last Reviewed: 11 Aug 2017
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