Chondrichthyans, sharks, rays, and chimaeras, have many crucial roles in maintaining stability of marine ecosystem. Many papers have reported the depletion of shark populations by overfishing. Furthermore, their low reproduction rate and slow growth to maturity make them highly vulnerable to fishing. Australia has a long history of shark fishing. The fishery has become more stringently managed in recent decades, but its impact on targeted populations is needs to be better understood.
This research uses surveys carried out across southern Australia over 4 decades to estimate the effects of fishing on five commercial species in three regions off southern Australia. Data from 438 sites were used, 184 off Western South Australia, 110 in Western Bass Strait, and 144 in Eastern Bass Strait. These sites were fished during three major surveys in the early-70s, mid-80s, and late 2000s. A set of gillnets with 5, 6, 7 and 8-inch mesh sizes was deployed at each site. Data preparation involved standardizing the efficiency of different mesh sizes, then clustering sites to meet the statistical requirements. One-Way Anova was implemented to estimate changes in relative abundances between survey periods. This will show if recent management has allowed stocks to recover.