| Spawning aggregations occur off the coast at 300 to 450 m depth in winter (May to September). Spawning takes place in August (Ref. 6390).
Mature gemfish undergo an annual spawning migration which begins with fish aggregating off northeastern Bass Strait in autumn, followed by movement of the aggregated fish into waters off New South Wales (Ref. 26613). The migrating schools usually reach the Sydney to Wollongong region by the end of June and typically peak in abundance during July. There can be some variability from year to year in the timing of the migration, but most fish reach the spawning grounds by early to mid-August. The only confirmed spawning area for gemfish in Australian waters is off the central to northern New South Wales coast (Ref. 28786), the western stock of gemfish spawns in waters west of Bass Strait.
The ratio of female to male gemfish in the spawning stock varies from year to year (Ref. 28790). For example, there was a higher percentage of females in the 1990 spawning run (Ref. 28791). |