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Abstract
The Australian Northern Prawn Fishery (NPF) is one of the few that has adopted a
dynamic version of a ‘maximum economic yield’ (MEY) target, and, on this basis, the
fishery is undergoing a process of substantial stock rebuilding. This study details the
bioeconomic model used to provide scientific management advice for the NPF, in
terms of the amount of allowable total gear length in the fishery, for both the MEY
target and the path to MEY. It combines the stock assessment process for two species
of tiger prawns with a specification for discounted economic profits, where the harvest
function in the profit equation is stock-dependent. Results for the NPF show a substantial
‘stock effect’, indicating the importance of conserving fish stocks for profitability.
MEY thus occurs at a stock size that is larger than that at maximum sustainable
yield, leading to a ‘win-win’ situation for both the industry (added profitability) and
the environment (larger fish stocks and lower impact on the ecosystem). Sensitivity
results emphasize this effect by showing that the MEY target is much more sensitive to
changes in the price of prawns and the cost of fuel, and far less so to the rate of discount.