It is well established in the fisheries economics literature that the optimal management offish stocks that are exploited by competing fisheries requires the establishment of a management regime that restricts the total catch harvested. These regimes may explicitly limit catch through the use of output, or catch, restrictions or implicitly through the use input controls. Optimal allocation of the total allowable catch between the sectors occurs where the marginal value of the last unit of catch taken by each sector is equal. However the application of this framework to many fisheries is limited.
An example of a fishery that competes with others for the available stock is the Queensland beam trawl fishery, which is based on the exploitation of estuarine prawn stocks and managed through limited entry regulations and input restrictions. The fishery has been subject to criticism as a result of its perceived impacts on recreational
fish stocks and offshore prawn stocks. In response to these concerns the Bums Inquiry into recreational fishing in Queensland recommended that beam trawling be phased out.
The purpose of this thesis is to conduct an analysis of the net economic benefit accruing from production activity in the Queensland beam trawl fishery, taking into consideration the consumption externality this activity imposes on recreational fishers, the production externality imposed on offshore prawn trawl operators, and of the management regimes in place in the respective fisheries. This is done through a bioeconomic analysis of the beam trawl fishery and its interactions with the recreational and offshore otter trawl fisheries.
The results of the analysis indicate that operators in the beam trawl fishery are capturing some of the resource rent arising from the productive nature of the prawn stock, although the effort level in the fishery is in excess of that
which is economically optimal. The results also indicate that, of the two externalities considered, only the production externality imposed on otter trawl operators is potentially of sufficient magnitude to justify a reduction or closure of the beam trawl fishery. However effort levels in the otter trawl fishery appear to be determined by competitive factors as opposed to the management restrictions in place in the fishery. Given this, it is likely that any potential economic benefits that may arise from the cessation or reduction of beam trawl effort will be dissipated as otter trawl effort levels increase in response. In considering this and other evidence, this thesis concludes that there is no economic justification for the closure of the beam trawl fishery at this time.