Research identified that almost all Murray cod in certain impoundments were raised in hatcheries, which led to removal of closed seasons in these waters

Impact summary

Murray cod spawn in large, impounded waters, but the successful recruitment of progeny from these events into the population was not known. This knowledge is important as recreational fishing regulations included a closed season for Murray cod to protect fish during the spring spawning period. Should fish populations contain mostly hatchery-reared Murray cod there would be no need for closed seasons as few, if any, wild fish exist. To understand the contribution of stocked Murray cod, hatchery-reared fish were marked with a chemical dye prior to release. These fish were recaptured up to 3 years post-release. The detection of chemical marks in fish sampled revealed that almost all Murray cod in Blowering and Copeton dams were of hatchery origin. This information underpinned the decision by fishery managers to remove the closed season in these impoundments, which allowed anglers to target Murray cod all year round in these locations.

Impact date	2018
Category of impact	Social Impact
Impact level	Adoption