8. Whaling Models for Cetacean Conservation
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management tool for the exploitation of whale stocks into the indefinite future. Because of the many uncertainties surrounding its use, one might argue
that the CLA should not be implemented until it has been rigorously evaluated. Such field trials would require several years or decades to complete. The
IWC Scientific Committee is divided on the issue of monitoring the performance
of the CLA (IWC 1993). Some members argue that intensive surveys of whale
populations are essential for the purpose of monitoring the effectiveness of
the CLA (Smith and Stokes 1993). Others argue that, given the poor precision
of current estimates of abundance, it is impractical to monitor the CLA in real
time. Alternatively, perhaps we should be monitoring other components of the
ecosystem.
Active adaptive management (Walters and Holling 1990) may afford the only
sound approach to structuring the management of the ecosystems that are home to
the world’s whale stocks. Adaptive management involves first using a model (e.g.,
the CLA) to synthesize how we think the system works and to formulate hypotheses. This is followed by active management intervention such as an experimental
harvest or management by protection. The system is monitored to see how well
we are able to predict the system’s behavior. The monitoring data are used to
evaluate the model predictions, followed by reformulation of the model. Adaptive
resource management is structurally like the modern scientific method but iterated
through time and in different areas to accommodate the fact that complex ecosystem processes cannot be replicated with a rigorous experimental design. The
idea of integrating science and management is not a new one, indeed; such an
experimental approach to evaluating the management of whale stocks was outlined 20 years ago (Allen 1980).
Conclusions
The IWC’s RMP makes use of a CLA with a simple density-dependent model that
only requires data on previous catch and current stock size from which to set catch
quotas. Although the underlying model is simple in structure, the algorithm is
designed to reduce harvests to compensate for uncertainty in a way that makes it
unlikely that overexploitation will occur when following the CLA. Careful consideration for uncertainty ensures that the RMP will be a safer model for governing whale harvests than its predecessor, the New Management Procedure. The
RMP’s Bayesian approach to interfacing data with the model affords a powerful
way to design ecological models. Nevertheless, problems with implementation
may remain due to excessive harvests under the CLA if there are unreported
harvests, overestimates of stock size, and failure to identify spatially structured
stocks.
To my mind, however, these problems pale in comparison to the fundamental
flaw that the RMP is a single-species approach to management that fails to
consider ecosystem structure and function in setting management objectives.
Despite knowledge that the krill-based ecosystem of the southern ocean has been
123
management tool for the exploitation of whale stocks into the indefinite future. Because of the many uncertainties surrounding its use, one might argue
that the CLA should not be implemented until it has been rigorously evaluated. Such field trials would require several years or decades to complete. The
IWC Scientific Committee is divided on the issue of monitoring the performance
of the CLA (IWC 1993). Some members argue that intensive surveys of whale
populations are essential for the purpose of monitoring the effectiveness of
the CLA (Smith and Stokes 1993). Others argue that, given the poor precision
of current estimates of abundance, it is impractical to monitor the CLA in real
time. Alternatively, perhaps we should be monitoring other components of the
ecosystem.
Active adaptive management (Walters and Holling 1990) may afford the only
sound approach to structuring the management of the ecosystems that are home to
the world’s whale stocks. Adaptive management involves first using a model (e.g.,
the CLA) to synthesize how we think the system works and to formulate hypotheses. This is followed by active management intervention such as an experimental
harvest or management by protection. The system is monitored to see how well
we are able to predict the system’s behavior. The monitoring data are used to
evaluate the model predictions, followed by reformulation of the model. Adaptive
resource management is structurally like the modern scientific method but iterated
through time and in different areas to accommodate the fact that complex ecosystem processes cannot be replicated with a rigorous experimental design. The
idea of integrating science and management is not a new one, indeed; such an
experimental approach to evaluating the management of whale stocks was outlined 20 years ago (Allen 1980).
Conclusions
The IWC’s RMP makes use of a CLA with a simple density-dependent model that
only requires data on previous catch and current stock size from which to set catch
quotas. Although the underlying model is simple in structure, the algorithm is
designed to reduce harvests to compensate for uncertainty in a way that makes it
unlikely that overexploitation will occur when following the CLA. Careful consideration for uncertainty ensures that the RMP will be a safer model for governing whale harvests than its predecessor, the New Management Procedure. The
RMP’s Bayesian approach to interfacing data with the model affords a powerful
way to design ecological models. Nevertheless, problems with implementation
may remain due to excessive harvests under the CLA if there are unreported
harvests, overestimates of stock size, and failure to identify spatially structured
stocks.
To my mind, however, these problems pale in comparison to the fundamental
flaw that the RMP is a single-species approach to management that fails to
consider ecosystem structure and function in setting management objectives.
Despite knowledge that the krill-based ecosystem of the southern ocean has been