Catch, Effort and CPUE

Whilst Southern Sand Flathead has a long history of commercial fishing in Tasmania, this species has only been distinguished from Tiger Flathead in fishery returns data since 2007/08. Previous stock assessment reports show back-calculated estimates of species-specific catch prior to 2007/08 (Krueck et al. 2020; Fraser et al. 2021). Commercial catches of Southern Sand Flathead are dwarfed by estimates of recreational catches available from recreational fishing surveys conducted since 2000/01 (Lyle 2005; Lyle et al. 2009; Lyle et al. 2014b; Lyle et al. 2019). In recreational fishing survey reports prior to 2017/18, recreational catch was reported for all flathead species combined, assuming that Southern Sand Flathead accounted for approximately 90% of reported catches (Lyle 2005; Lyle et al. 2009; Lyle et al. 2014b). For all flathead species combined, recreational catches were estimated at 361 t in 2000/01 (Lyle 2005), 292 t in 2007/08 (Lyle et al. 2009), and 235.9 t in 2012/13 (Lyle et al. 2014b). In 2017/18, the recreational fishing survey for the first time distinguished between Southern Sand Flathead and Tiger Flathead, finding Southern Sand Flathead represented 96% of total Flathead catch by number (Lyle et al. 2019). The recreational catch of Southern Sand Flathead was estimated at 184.4 t in 2017/18 (Lyle et al. 2019), which was approximately 98% of the estimated total catch (recreational and commercial combined) in that season.

The distribution of catch and effort is concentrated in the most populated regions across Tasmania. Almost all commercially harvested Southern Sand Flathead has recently been taken by handline on the east, southeast, and northwest coasts. In the recreational fishery in 2017/18, just over half of estimated total Flathead catch was derived from the southeast coast, with the central east (including Great Oyster Bay) and northwest coasts also representing important regions (Lyle et al. 2019).

Although commercial catches are insignificant for this species, it is worth noting that commercial handline CPUE shows an overall declining trend. This was associated with a clear overall decline in commercial handline effort. However, regional differences highlight that these trends could mask spatial heterogeneity in fishing activity or population dynamics.