Martin Marzloff

Dynamics of rocky reefs and fishers in eastern Tasmania: Modelling using a complex systems approach

Supervisors: Dr. Craig Johnson (UTAS), Dr. Stewart Frusher (UTAS), Dr. Rich Little (CSIRO), Dr Jeff Dambacher (CSIRO).

Project

The major goal of the project is to develop a heuristic model of the dynamics of the rocky reef ecosystem on the east coast of Tasmania , and interactions of fishers with this ecosystem. It is anticipated that the models will provide valuable visualization and decision support tools for managers.

The overall approach will develop agent-based models of the system, focusing on emergent properties at multiple scales. As a minimum, local models will interact with regional-scale models in describing biophysical processes and fisher behaviour.

The biophysical component will attempt to capture known key interactions among important species (e.g. rock lobsters, abalone, sea urchins, reef-associated fishes, and marine algae), and identify key non-linearities in system behaviour. Particular attention will be given to formation of ‘barrens' habitat as a result of overgrazing by sea urchins.

Actual behaviour of fishers will be compared to that predicted on the basis of underlying local ‘decision rules', which might, for example, range from optimizing profit to individual's decisions to limit the range of their fishing activity.

Objectives

1. Review existing qualitative and quantitative MSE models (biological, social and economic) and identify appropriate models for Tasmania's inshore reef ecosystem (eg. abalone-rock lobster (and urchin)).
2. Validate the models against existing data, information and understanding.
3. Use the model to investigate alternative resource allocation strategies at the ecosystem level to inform the management process for Tasmania's two most valuable fisheries.