A RECENT survey of two-spined blackfish in the North East region completed by Arthur Rylah Institute as part of an ongoing environmental monitoring program by AGL Energy, showed a significant increase in two spined blackfish numbers in 2018 compared to previous years. The monitoring program in the Kiewa River catchment commenced in 1998 and continues to date, and has been used to demonstrate that there are no detectable adverse impact of current desilting practices on two-spined blackfish abundances and population structure. Blackfish are used as a key indicator species due to them being vulnerable to impacts from sedimentation.