An Evaluation of Management Strategies for Line Fishing in the Ningaloo Marine Park

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Little, Rich; Thebaud, Olivier; Boschetti, Fabio ORCID ID icon; McDonald, David; Marriot, Ross; Wise, Brent; Lenanton, Rod


2011-09-01


Report


120 p


This research has concentrated on the use of ELFSim for shedding light on the effects of fishing in the Ningaloo Marine Park on a key target species. The original objectives of the NRP were much broader than this, however, but as NRP results become available from other projects, it will be possible to provide a more encompassing MSE for integrated management of the Ningaloo Marine Park. The results reported above demonstrate both the variability and trends in a range of indicators for the Ningaloo recreational fishery, target species Spangle Emperor. This species is thought to be a critical component of the Ningaloo marine ecosystem and so we explored different under different management strategies and a range of bio-physical and human-usage scenarios. The results reveal the effect of a range of management strategies under current environmental conditions, and under a range of future scenarios. These model-based results may not only agree with public perception, but can also help to pinpoint the most important features of the biology and human exploitation that give rise to the changes, and how management agencies might best set their strategies in order to achieve their stated objectives. Whether the objectives were achieved for the sanctuaries depends on how the sanctuaries were defined. Under current conditions, controlling inshore fishing would seem to be the strategy that best achieves the objectives. There is a great deal of uncertainty however with this result because there is very little reliable estimates of how many fish are being removed in this manner. We assumed that the inshore effort was equal to the most recent boat-based off-shore effort of 12 000 boat days (Figure 2). The accuracy of this assumption may become more clear as other work in the marine park emerges. Although we identified that unregulated inshore fishing might prevent the achievement of the management objectives, there would be great difficulty in determining methods of controlling inshore fishing, with effective fishing compliance. For the purpose of this report, we assumed that the sanctuaries along the coast ended at the high water mark and thus any fishing from the shore actually occurred in them. If the definition of the sanctuary was that it ended at some point offshore, and so would technically allow fishing from shore to occur, then these results do not reflect such a definition. The spatial scale at which the model operates means that it is also not possible for the model to spatially resolve such a difference in the definition of sanctuary boundaries. The results also showed that sanctuaries can be useful in controlling a possible increase in fishing pressures but that they are not particularly effective in dealing with potentially impending environmental change. Only control of catch, or even effort if technological creep can be controlled, was capable of doing this. Indeed under the Env Press and the composite scenario Env Pressure + Tech creep, the equilibrium conditions actually change because the natural mortality changes, and so even in the absence of fishing it is possible that the population will not return to the equilibrium conditions. We did not determine though the possibility of maintaining effort and having only a catch-and-release fishery. Such a fishery could prevent compounded pressure on the stock from fishing and environmental changes. Such a fishery also requires a high amount of compliance from the community and it might be doubtful as to whether this would occur in a place with such a high transient population. One development that was not included in this report but has helped with the development of management strategies with stakeholders is the cross-project exploratory tool ScenarioLab (Boschetti et al. 2010). This tool was used to provide rapid assessment of alternative management strategies under a range of bio-physical and social scenarios appropriate to the Ningaloo Marine Park to the stakeholders. The p


CSIRO


management strategy evaluation


Environmental Management; Natural Resource Management


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https://doi.org/10.4225/08/585189b006dad


This report has been placed on the CSIRO repository and may be made available to persons outside of CSIRO for non commercial purposes, in its entirety and without deletion of disclaimers and copyright information.


EP106710


Client Report (Author)


English


Little, Rich; Thebaud, Olivier; Boschetti, Fabio; McDonald, David; Marriot, Ross; Wise, Brent; Lenanton, Rod. An Evaluation of Management Strategies for Line Fishing in the Ningaloo Marine Park. CSIRO; 2011. <a href="https://doi.org/10.4225/08/585189b006dad" target="_blank">https://doi.org/10.4225/08/585189b006dad</a>



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