4.3 Trophic interactions and ecosystem modelling

Description

This project permitted completion of a major assessment of historical fisheries data to determine, using the internationally accepted modelling approach, if any significant ecosystem-wide trophic impacts had occurred over the past 30 years in Western Australia’s marine waters.

New data collection included implementation of experiments on rock lobster abundance and foraging behaviour, along with detailed examination of types and quantities of invertebrates in fished and unfished areas for deep and shallow water rock lobster habitats.

An approach to develop a better understanding of the broader potential anthropogenic impacts on ecosystems was undertaken via trialling of sophisticated modelling approaches to the Peel Harvey estuary, identified as the most at-risk ecosystem during the EBFM risk assessment process.

A key risk for trophic integrity was identified for the west coast demersal scalefish fish resource. A review of information on diets of species in the West Coast Bioregion was used to develop a food web. Pink snapper and skippy (the dominant local trevally species) were two important exploited species in the West Coast Bioregion for which more dietary data were collected as part of this study.

Aims

• The primary aim for the project was to develop a greater understanding of trophic interactions within the West Coast Bioregion and the potential for these interactions to be affected by fishing and other factors, such as climate change.
• To investigate trophic interactions in the marine environment
• To develop an understanding of the value and application of ecosystem models for the Peel-Harvey estuary.

Reports

Metcalf, S. J., Pember, M. B. and Bellchambers, L. M. 2011. Identifying indicators of the effects of fishing using alternative models, uncertainty, and aggregation error. ICES Journal of Marine Science, 68: 1417–1425. doi.org/10.1093/icesjms/fsr050

Metcalf, S.J., Dambacher, J.M., Rogers, P., Hall, N., Loneragan, N. and Gaughan, D.J. Identifying key dynamics and ideal governance structures for successful ecological management. Environmental Science & Policy (2014) doi.org/10.1016/j.envsci.2013.07.005