Spangled emperor, a demersal (bottom-dwelling) fish, is a target for recreational fishers and also a minor component of the catch in several commercial fisheries in Western Australia. We manage both sectors together to ensure long-term sustainability of the species.
Spangled emperor is a popular target for recreational fishers in the Gascoyne Coast Bioregion.
This species is also caught recreationally in the West Coast Bioregion. In response to data indicating overfishing in this bioregion in recent years, we took extra measures to reduce the catch in the bioregion, with the aim of keeping catches at less than 50 per cent of 2005/06 levels.
Introduced measures include an annual two-month closed season for recreational fishing for demersal species and reduced bag limits. Commercial wetline and demersal gillnet and longline fishing has been closed from Lancelin to Mandurah.
The exact amount of spangled emperor taken by recreational fishers in the North Coast Bioregion is not known but charter fishers are estimated to take only about one per cent of the entire demersal catch and the overall recreational catch is known to be small compared with the commercial catch. With increasing populations in the Pilbara and Kimberley due to mining, oil and gas developments, recreational catches are likely to increase in future.
In the commercial sector, the Pilbara Demersal Scalefish Fisheries, which include trawl, trap and line fisheries, take most spangled emperor. Also in the North Coast Bioregion, the commercial Northern Demersal Scalefish Managed Fishery, which operates off the Kimberley coast.
Commercial fishing management measures include gear and zone restrictions, a minimum size limit for taking spangled emperor, limits on the number of permits and fishing vessels and effort allocations (allocations of fishing time).
Monitoring, assessment and research
Data from log books submitted by commercial fishers and information from VMS is analysed to assess stock status of each species.
In the Gascoyne Coast Bioregion, spangled emperor is an ‘indicator species’, meaning its stock status, along with the status of several other species, is used to indicate the status of stocks of all demersal fish in the bioregion.
Ongoing monitoring continues with a trial of low-cost methods including biological sampling at tournaments and on collections of carcasses at public filleting tables.
A study carried out in collaboration with CSIRO focused on fishing of spangled emperor in the Ningaloo Marine Park. The results were used to look at the potential influence of increases in water temperatures and cyclone activity on different management strategies.