出版社：Government of Western Australia / Department of Fisheries
摘要：The Department of Fisheries, Western Australia is currently developing a framework to assess
the most appropriate methodologies for the implementation of Ecosystem Based Fisheries
Management (EBFM) in Western Australia. The implementation of EBFM can be considered
as an operational extension of Ecologically Sustainable Development (ESD), the principles
of which were adopted by Western Australia for application in the management of fisheries
in 2002. EBFM aims to assess and manage ecological impacts as well as social and economic
outcomes related to fish and fisheries at a regional level. The degree to which EBFM will
be implemented in terms of activities or processes, additional to those fishery management
processes currently in place for the Department, has yet to be ascertained. This report forms
part of a project designed to address the question as to what benefits EBFM could generate if
applied in Western Australia.
Fisheries management in WA has traditionally focused on maintaining the sustainability of
targeted stocks and, as such, has comprehensive data sets on the catches, biology and ecology
of many exploited stocks. There are limited quantitative data regarding the ecosystem, social
and economic impacts of fisheries and limited formal consideration of the roles of external
drivers and governance. Beyond these limitations there is also the challenge to identify
linkages and important relationships both within ecosystems (including exploited stocks), and
across social, economic and governance facets of fisheries management.
Qualitative modelling (also known as loop analysis) uses feedbacks to investigate the impacts
of perturbation on system stability and produce predictions of change in ecological, social and
economic aspects of systems. This technique may be used when quantitative data is lacking,
as it requires only the signs of interactions between model variables (i.e. positive, negative or
zero). For example, there may be qualitative information based on expert opinion suggesting
that an increase (perturbation) in the number of iconic fish in an area has a positive effect on
the general community through the maintenance of cultural and heritage values. Qualitative
modelling can also be used to identify the critical thresholds for change in a system and may
be useful to highlight data gaps and identify important relationships. Such information, along
with the capacity to investigate system stability, can allow the examination of the efficacy of
alternative management strategies and be used to indicate likely methods of aiding species
recovery following perturbation.
Qualitative modelling was used to investigate five separate systems within the West Coast
Bioregion. Ecosystem dynamics and the importance of social and economic links were examined
using different scenarios for each of the five systems. The systems included: the role of direct
stakeholders in influencing government decisions; management needs in Cockburn Sound;
the impacts of the market on the western rock lobster fishery; and alterations to recreational
fisher behaviour following hypothetical changes in management. Investigations involved the
examination of system stability and the inclusion/removal of links between particular variables
of interest to compare predictions between alternative models. In addition, model predictions
following a positive perturbation (i.e. positive disturbance or increase) to specific variables
were also used to examine various scenarios.
Collaboration between the government and direct stakeholders, such as commercial fishers, was
found to increase the stability of the West Coast Bioregion model. In addition, the relationship
between fish, the fishery and fisheries management was identified as an important driver in the
Cockburn Sound ecosystem. Strong management, as well as additional management external to the Department, was shown to be able to counteract the negative effects of coastal development
or industry on fish populations and sediment in the water column.
The western rock lobster model reinforced the importance of management and the regulation of
rock lobster fisheries in Western Australia to ensure the fishery remains sustainable and is not
driven solely by profit. The role of price, demand and illegal fishing in the abalone fishery were
also investigated and the analysis identified the need for continued strict regulation of illegal
harvest. In addition, if the fishery is to remain economically viable, the need for management
to take market impacts into account is necessary, particularly if changes to the management of
the abalone fishery occur in the future.
A model of recreational fisher behaviour was produced to investigate the impact of a hypothetical
seasonal closure to recreational fishing for a suite of demersal fish species in the metropolitan
zone. A seasonal closure was predicted to have positive impacts on protected demersal fish
populations but negative impacts on the abundance of all other fish species. The response of
these populations depends on the strength of effort reductions by management versus an effort-
shift towards targeting alternative species. This model also highlighted the potential impact of
a ‘spike’ in fishing pressure outside of the closed season. It is recommended that quantitative
data collection regarding the likely changes in fisher behaviour be undertaken.
Recreational fishing and the management of recreational fisheries were found to be important
in a number of the qualitative modelling scenarios. Further data collection on the impacts of
recreational fishing and the socio-economic drivers behind recreational fishing are essential.
In addition, quantitative information on economic factors such as demand, the influence of the
international market and the Australian dollar on fisheries exports should be undertaken. This
would allow more comprehensive models of the fishery economy to be produced. In addition,
quantitative estimates of the existence of illegal fishing and the influence of lobby groups could
assist in the development of new management strategies.
Additional management strategies were found to be necessary in the recreational fishing
models. Furthermore, social assessments, including the assessment of fisher behaviour, will
be an important source of information for the production of future models. To improve the
outcomes generated by qualitative models, the social and economic data should be structured
to provide relevant data to management and to update the models.
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