Impacts of vessel capacity reduction programs on the efficiency in fisheries. The case of Australia's multispecies in northern prawn fishery

Capacity reduction programs in the form of buybacks or decommissioning programs have had relatively widespread application in fisheries in the US, Europe and Australia. A common criticism of such programs is that they remove the least efficient vessels first, resulting in an increase in average efficiency of the remaining fleet. The effective fishing power of the fleet, therefore, does not decrease in proportion to the number of vessels removed. Further, reduced crowding may increase efficiency of the remaining vessels. In this paper, the effects of a buyback program on average technical efficiency in Australia’s Northern Prawn Fishery are examined using a multi-output distance function approach with an explicit inefficiency model. The results indicate that average efficiency of the remaining vessels was greater than that of the removed vessels, and that average efficiency of remaining vessels also increased as a result of reduced crowding

A case study in successful management of a data-poor fishery using simple decision rules: the Queensland spanner crab fishery

The Queensland spanner crab Ranina ranina is the target of a relatively data-poor, low-value fishery that has been managed for the last decade by using total allowable catches (TACs) in an individual transferable quota system. Despite the fact that this management system is usually applied to data-rich fisheries, it has been successfully used on this data-poor fishery. The key factor has been the use of harvest strategies that consisted only of simple decision rules that were appropriate given the size of the fishery and knowledge of the resource. These strategies were tested in a management strategy evaluation framework; however, it was not traditional in that (1) the operating model (or “true” resource to be managed) was not conditioned to data but rather was set to parameter ranges seen as appropriate for the resource and (2) the TAC was not set by using a stock assessment model, so the magnitude of the stock biomass was unknown. The important test was whether one could develop harvest strategies that were robust to this large uncertainty in knowledge by using only commercial catch rates. The management system had to be adaptive over time as more was learned about the biology of the species and how the harvest strategies affected the management of the fishery. This meant that the TAC was almost always set using the harvest strategies, but modifications to the decision rules were made on several occasions as more was learned about the fishery. The transparency and simplicity of the rules mean that the industry was empowered to make significant contributions to fine tuning the harvest strategies. As a result, the process does not rely solely on scientific advances but on the pooled knowledge of scientists, industry, and managers in a cooperative environment

Towards adaptive approaches to management of the South African abalone haliotis midae fishery

The South African abalone Haliotis midae resource is widely perceived as being under threat of overexploitation as a result of increased poaching. In this paper, reservations are expressed about using catch per unit effort as the sole index of abundance when assessing this fishery, particularly because of the highly aggregatory behaviour of the species. A fishery-independent survey has been initiated and is designed to provide relative indices of abundance with CVs of about 25% in most of the zones for which Total Allowable Catchs (TACs) are set annually for this fishery. However, it will take several years before this relative index matures to a time-serieslong enough to provide a usable basis for management. Through a series of simple simulation models, it is shown that calibration of the survey to provide values of biomass in absolute terms would greatly enhance thevalue of the dataset. The models show that, if sufficient precision (CV 50% or less) could be achieved in such a calibration exercise, the potential for management benefit is improved substantially, even when using a relatively simple management procedure to set TACs. This improvement results from an enhanced ability to detect resource declines or increases at an early stage, as well as from decreasing the time period until the survey index becomes useful. Furthermore, the paper demonstrates that basic modelling techniques could usefully indicate which forms of adaptive management experiments would improve ability to manage the resource, mainly through estimation of the level of precision that would be required from those experiments. The results of this study are particularlyapplicable to fishing zones for which there are insufficient other data to perform a standard stock assessment

Reforging Ockham’s Razor: an enquiry into the ontology of parsimony arguments

Nearly every philosopher in English-speaking world has heard of Ockham’s Razor, which is given in one of two ways, don’t multiply entities beyond necessity and all things being equal choose the simpler explanation. Yet it is unclear from the scholarship whether the use of Ockham’s Razor is justified in science and philosophy. However, if it can be shown to ‘get’ us truth, it would gain an unequivocal justification, as disputes that are continued after the parties to the substantive truth of one or the other are defined as frivolous. Alternative, one may contend that explanation could have other criteria of success. The implication of a direct connection between the razor and truth comes with ontological commitments, namely a commitment to realism (about universals) and philosophical theism. This is contrary to the razor’s use as a tool of nominalism and naturalism. I argue in this thesis there that the only possible non-circular justification for Ockham’s Razor is truth and that therefore certain philosophical positions are excluded from using the razor to animate their positions. There is an additional, second criteria for the success of our inquiry, namely the justification must in some way be consistent with the razor, which means the chosen explanation for the razor, must be simpler than any of its rivals and not have superfluous entities, otherwise our justification would be contrary to the advice of the razor. We are presented with a Scylla and Charybdis type problem, we avoid a circularity on the one hand and on the other we must not contradict the razor itself, these are contrary intellectual impulses. So firstly I will look at disciplines outside philosophy for some initial inspiration. If we could answer this question in a ‘non’ philosophical way, the problem would have solved itself in a way that require little change of practice. If lawyers or scientist can account for the razor properly, there is not really a problem of justification, at least not a philosophical one. Second, I consider the realist and theist positions, namely an argument of Aristotle’s in the Posterior Analytics and part of Aquinas’ On the Divine Simplicity. Further, I consider the work of Ockham as a nominalist. Lastly, I consider modern and contemporary philosophy, in the form of Hume, Quine and Sober (a modern writer on the razor). The aim here is to ‘stress test’ the philosophical resources of the various systems and analyse the results to see if they can produce a non-circular result.Thesis (MA) -- Faculty of Humanities, Philosophy, 202

Scoping current and future genetic tools, their limitations and their applications for wild fisheries management

The overarching goal of this project was to prepare a document that summarises past, present and emerging ways in which research using genetic technology can assist the Australian fishing industry to maintain productive and sustainable harvests. The project achieved the following specific objectives: 1. Documented existing and prospective biotechnologies and genetic analysis tools that are relevant to wild fisheries management, and their availability and application at a national and international level; 2. Documented the FRDC’s past and current investment in biotechnology and genetic tools used in wild fisheries management research; 3. Documented the different biotechnology and genetic tools that are being used in wild fisheries management research in Australia, and the nature and location of key research groups; 4. Described what management question each tool has been used for (e.g. stock structure, biomass estimation, product provenance, disease monitoring); 5. Identified those tools and approaches (existing and future) most likely to deliver significant advances in fisheries management; 6. Identified the potential for collaborations which could improve the focus and impact of work in this area

Management objectives of Queensland fisheries: Putting the horse before the cart

A review of future management arrangements for the Queensland East Coast Trawl fishery was undertaken in 2010 to develop a management plan for the next 10 years. A key question raised at the start of the review process was: what should the management plan achieve? As with fisheries management in most countries, multiple management objectives were implicit in policy statements, but were poorly specified in some areas (particularly social objectives) and strongly identified in others (e.g., an objective of sustainability). As a start to the management review process, an analysis of what objectives the management system should aim to achieve was undertaken. A review of natural resource management objectives employed internationally was used to develop a candidate list, and the objectives most relevant to the fishery were short-listed by a scientific advisory group. Additional objectives specific to Queensland fisheries management, but not identified in the international review, were also identified and incorporated into the objective set. The relative importance of the different objectives to different stakeholder groups was assessed using the Analytic Hierarchy Process. As with other studies, the relative importance of the different objectives varied both within and between the different stakeholder groups, although general trends in preferences were observed

Sustaining productivity of tropical red snappers using new monitoring and reference points

OBJECTIVES: 1. Analyse current monitoring and logbook data sets, as well as survey and other information,to establish whether these data provide sufficient power to develop critical indicators of fishery performance. 2. Provide a risk analysis that examines the use of age structure and catch rate information for development of critical indicators, and response rules for those criteria, in the absence of other fishery information. 3. Develop a monitoring program that uses commercial vessels from the fishery to provide independent data

Rapid response to abalone virus depletion in western Victoria: information acquisition and reef code assessment

Future management of disease-affected abalone must adapt to the changing circumstances, and adopting a precautionary approach will allow maximum potential for stock recovery. This approach is mandated by the observation that no documented examples are known of abalone populations recovering from catastrophic impacts such as have occurred in the abalone fisheries of Victoria's Western and Central zones. Indeed the balance of international evidence points towards the contrary, so these fisheries are in dangerous territory. This need not mean that recovery cannot occur. However, the modelling results from this project confirm the above precautionary view and suggest that unless it is known with certainty that disease-induced mortalities have been moderate (less than 40%), then any resumption of fishing in the near term risks the future of the fishery. Acquisition of accurate mortality data is the only basis upon which fishing can recommence in the short term (within 5 years) and in many instances, such as for some among those reefs considered in our study, the opportunity has passed. The simulation results provide guidance, but their validity is conditional on myriad assumptions as well as on the accuracy of data employed. We already know that catches early in the fishery’s history were higher than reported officially, but how much higher is conjecture. Growth is highly variable over small spatial scales and feedback effects from reduced abundance together with changed size structure and persistence of habitat will play roles in determining the rate, if any, of recovery. The extent of the contemporary illegal catch is uncertain, particularly given the unprecedented closure of the fisheries. The results show that even small illegal catches can significantly degrade recovery where the viral impact is high, with clear implications for the enforcement aspects of managing these fisheries