The Effect of a Period of Increased Legal Minimum Length of Sea Mullet in Westeren Australia

Abstract

Following allegations of a depletionary trend in the mullet stocks a conservation scheme was initiated in Western Australia in 1942 by raising the legal minimum length in successive stages. In 1946 the legal length reverted to that in force before 1942. As far as can be seen from the catch statistics, the stocks did not benefit by the restriction period, the catches being of the same order before and after. It is possible that an increase in stocks occurred in the Shark Bay area, but as the fishery in this region was under-developed prior to the inception of the scheme there is no data to confirm such a supposition. The course of the Shark Bay fishery should be closely watched for any signs of overfishing now that the stocks are being more fully exploited. It would appear that no alteration in minimum lengths will effect an increase in the mullet stocks of the estuaries. There has been a definite decline in the mullet population of the Swan River since the early part of the century. This could be due to environmental changes rather than an effect of overfishing.