Macquarie perch Macquaria australasica is listed as endangered under national and state legislation. The species is now confined to a handful of self-sustaining populations across its range, several of which are in rivers with regulated flows. One of these rivers is the Upper Murrumbidgee River, with a large regulating storage (Tantangara Dam, storage capacity 252 GL, altitude 1256 m) at its head. Tantangara is part of the Snowy Scheme and diverts approximately 99% of inflows across the range into the coastal Lake Eucumbene. Releases from Tantangara are managed by Snowy Hydro, with environmental releases made since 2005 and since 2010-11 a major objective of annual flow releases has been to enhance spawning of Macquarie perch. Flows for this purpose have been released from 2010/11 onwards, with 2011/2012 being the largest volume of water ever released (or likely to be released) from Tantangara. A small sample of otoliths from Young-of-Year (YOY) Macquarie perch collected at Kissops Flat (18 km upstream of Cooma) in mid-2011, early-2012, and early-2013 were daily aged, and spawning dates estimated by back-calculation. In 2012 spawning occurred from late October-mid December and in 2012 in November. Calculated spawning dates from 2010 are problematic and will be discussed. Correlation of spawning with water temperature is unclear, possibly as a result of the highly regulated flows in the river and cyclic releases from Tantangara. Spawning dates and cues in the upper Murrumbidgee are compared with lower altitude populations of this species.