14.6. Qu estions and Tasks
327
influence of density-dependent effects in combination with fishing-induced
mortality and interregional movement , and more research into the quantification of these effects is encouraged.
The interactive model simulation approach chosen here has made it po ssible for us to identify a numb er of system features that are relevant to the
dynamics of the species under exploitation. Even though the model is
based on a set of simplifying assumptions, time trends in population dynamics are consistent with current observations (US Department of Commerce 1996). To prom ote consensus on the relevant data and appropriate
management methods, expansions and refinements of the model are currently underway in each of its three contributing fields, namely biology ,
economics and management. Those extensions include studies of management methods for recruitment and changes in habitat, development of alternately stable ecosystems on Georges Bank, as well as studies into determinants for annual adjustment in effort. Finally, in an attempt to reflect the
realities of commercial fishing more accurately, efforts are currently being
made to further incorporate the perspectives of fishermen and policy makers into the modeling process, and enable stakeholders to play out on the
computer their understanding of the system's workings.
Our dynamic modeling process is an iterative one , with additional information contributing to the overall significance of the simulation at each
step along the way. The model presented here is but a first step in the effort to capture the dynamics of the groundfishery on Georges Bank. The intended expansions to the model explained above are also points of departure , each no doubt contributing to the further specification of numerous
processes at work within the system in an attempt to better understand the
resource's dynamics, and in so doing possibly avert its collapse.
14.6 . Questions and Tasks
1. Conduct a sensitivity analysis on the annual rate of technological change
in the fishery. How do the three fish populations respond to rates 5%,
10% and 15% technological change? How are profits in the fishery
affected?
2. How much must fishing effort be reduced to ensure sustainable populations of each of the three species? Conduct a sensitivity analysis on fishing
effort. Can you stabilize all three popula tions at levels greater than zero?
3. How can the effect of marine protected areas be incorporated into the
model?
4. Experiment with fish movement rates. How do the model results change
when one species is highly migratory? What occurs if one species is
highly sedentary?
327
influence of density-dependent effects in combination with fishing-induced
mortality and interregional movement , and more research into the quantification of these effects is encouraged.
The interactive model simulation approach chosen here has made it po ssible for us to identify a numb er of system features that are relevant to the
dynamics of the species under exploitation. Even though the model is
based on a set of simplifying assumptions, time trends in population dynamics are consistent with current observations (US Department of Commerce 1996). To prom ote consensus on the relevant data and appropriate
management methods, expansions and refinements of the model are currently underway in each of its three contributing fields, namely biology ,
economics and management. Those extensions include studies of management methods for recruitment and changes in habitat, development of alternately stable ecosystems on Georges Bank, as well as studies into determinants for annual adjustment in effort. Finally, in an attempt to reflect the
realities of commercial fishing more accurately, efforts are currently being
made to further incorporate the perspectives of fishermen and policy makers into the modeling process, and enable stakeholders to play out on the
computer their understanding of the system's workings.
Our dynamic modeling process is an iterative one , with additional information contributing to the overall significance of the simulation at each
step along the way. The model presented here is but a first step in the effort to capture the dynamics of the groundfishery on Georges Bank. The intended expansions to the model explained above are also points of departure , each no doubt contributing to the further specification of numerous
processes at work within the system in an attempt to better understand the
resource's dynamics, and in so doing possibly avert its collapse.
14.6 . Questions and Tasks
1. Conduct a sensitivity analysis on the annual rate of technological change
in the fishery. How do the three fish populations respond to rates 5%,
10% and 15% technological change? How are profits in the fishery
affected?
2. How much must fishing effort be reduced to ensure sustainable populations of each of the three species? Conduct a sensitivity analysis on fishing
effort. Can you stabilize all three popula tions at levels greater than zero?
3. How can the effect of marine protected areas be incorporated into the
model?
4. Experiment with fish movement rates. How do the model results change
when one species is highly migratory? What occurs if one species is
highly sedentary?