Status of the Fishery for Sea Mullet ( Mugil cephalus Linnaeus) in Eastern Australia

Various shortcomings of the statistical systems in vogue in the fisheries of the eastern States of Australia are discussed from the viewpoint of a biologist. It is impossible to compute an estimate of the catch per unit of effort involving a time factor. The annual mullet catch for the whole eastern seaboard has remained substantially about 11,000,000 lb. for the past 10 years, but the total caught in any subdivision of the area has fluctuated widely. The Clarence River, Port Macquarie, Maryborough, and Wallis Lake areas are the most important producers. There is a high degree of correlation between the fluctuations in the mullet catch and those in the total catch of estuarine fish. The size and age composition of the mullet catch have shown only slight variation over the last 10 years, and there is no significant variation in this respect from the composition in 1903. The fluctuations in catch and catch per man are not inconsistent with theories of overfishing nor with those of natural population cycles; but the only theory which receives confirmation independently of the curves of catch and of catch per man is an economic one. Competition from both the trawling industry and the import industry has been responsible for the characteristics of the estuarine catch curves. It is estimated that the weight of fish flesh to be gained from recent changes in the management of the fishery could at best be considerably less than the amount of annual variation in the catch.