*

Red Emperor occur throughout the Western Pacific and Indian Oceans [Allen 1985]. The species' Australian distribution encompasses the entire northern coastline, from Cape Naturaliste in WA, around to the east coast, occasionally extending as far south as Sydney. All stocks of Red Emperor in Australia are considered sustainable.

Red Emperor is widely distributed throughout the Western Pacific and Indian Oceans, ranging from western and eastern Australia to southern Japan, and westward to east Africa and the southern Red Sea (Allen 1985). Within Australia, Red Emperor range from Cape Naturaliste (33°30’ S) in Western Australia, north and east across northern Australia and down the east coast to Sydney in New South Wales. Red Emperor in Western Australia is exploited primarily in the North Coast Bioregion [Newman et al. 2020]. Smaller catches are taken in the Northern Territory and Queensland. Red Emperor is one of the indicator species used to assess the status of the demersal resources in the North Coast Bioregion [Newman et al. 2018].

van Herwerden et al. [2009] examined the genetic connectivity of Red Emperor using mitochondrial DNA from samples collected at two locations in Western Australia (Browse Island, Kimberley region; Montebello Islands, Pilbara region) and two locations on the east coast (High Peak Island and Catfish Shoal, East Coast Queensland). The mitochondrial DNA data for Red Emperor did not differ genetically either within or between coasts at the locations examined, suggesting a panmictic population structure with high levels of gene flow among populations. This study indicates that eastern and western Australian populations of Red Emperor form a single inter-breeding genetic stock [van Herwerden et al. 2009] or one biological stock. The results of van Herwerden et al. [2009] confirm those derived by Johnson et al. [1993] using allozymes for Red Emperor in Western Australian waters. Johnson et al. [1993] examined allozyme samples of Red Emperor from the Lacepede Islands, Bedout island, Lowendal Islands, Ningaloo and Shark Bay. This study reported extensive connectivity and gene flow among populations throughout the sampled range of 1,400 km in Western Australia.

Stephenson et al. [2001] examined stable isotopes in sagittal otolith carbonates of Red Emperor from four locations; Shark Bay (Gascoyne), Ningaloo (Gascoyne), Pilbara and Broome (Kimberley). Significant differences in stable isotope ratios provided evidence that there was limited mixing of adult Red Emperor between three broad zones; Shark Bay (Gascoyne), Pilbara, and Broome (Kimberley), a distance of approximately 1,400 km [Stephenson et al. 2001]. Therefore, these broad locations could be managed separately for the purposes of fishery management, if management arrangements were established to harmonise with the spatial patterns of exploitation. Stephenson et al. [2001] reported partial mixing of Red Emperor from Pilbara west and east sites. The overlap in the multivariate analyses of otolith stable isotope signatures between some sites potentially reflects dispersal by a proportion of juvenile or adult fish. This suggests that, in Western Australia, Red Emperor can be managed as a number of separate management units. Additionally, Saunders et al. [2018] used otolith microchemistry and parasitology to identify separate biological Red Emperor stocks in the Joseph Bonaparte Gulf, Timor Sea, Arafura Sea and Gulf of Carpentaria.

Here, assessment of stock status is presented at the management unit level — Gascoyne, Pilbara and Kimberley (Western Australia) and East coast (Queensland); and at the biological stock level for the Joseph Bonaparte Gulf, Timor Sea, Arafura Sea and Gulf of Carpentaria.

East Coast Queensland

Red Emperor is mainly caught by hook and line with the majority harvested within the Great Barrier Reef Marine Park (GBRMP) The first east coast Red Emperor stock assessment was completed in 2022 and indicated biomass levels have remained at between 55 to 60% since 2005 [Sumpter et al 2022]. Stock biomass in 2021 was estimated at 58% of unfished levels, with the assessment providing a range of estimates across scenarios from 56–65%. Red Emperor is regionally important to recreational fishers, and it is regarded as a trophy fish. In the 2019–20 survey, the annual recreational Red Emperor harvest was estimated at 58 t; down from 74 t in the 2013–14 [Teixeira et al. 2021]. This equates to around 64% per cent of the total Red Emperor landed on the Queensland east coast in 2019-20. The five-year harvest average for the charter fishery was 13 t. 

In the commercial fishery, reported harvests declined from 100–200 t per year (1998–99 to 2003–04) to less than 61 t per year. This decrease coincided with the expansion of no-take marine reserves in the GBRMP and the introduction of a quota management system for the Reef Line Fishery (RLF). A portion of the biomass is afforded soem protection from fishing by zoning in the GBRMP although this has not been quantified. Over the last decade, annual commercial catches have shown a general decline from 61 t (2009–10) to 31t (2021–22). Over this same period, the number of vessels landing Red Emperor within the RLF reduced from 210 (2009–10) to 173 (2017–21 average).

Red Emperor is a secondary target and by-product species in the Reef Line Fishery. Commercial harvest in this fishery is constrained by a multi-species total allowable commercial catch (TACC). The long-term management of the species is also guided by the Reef Line Fishery Harvest Strategy: 2020–2025 [QDAF 2020]. The strategy includes species-specific harvest control rules and catch reference points for secondary target species to control fishing pressure and effort shifts. For instance, if the east coast Red Emperor harvest exceeds catch reference points, control rules will trigger an interim species specific TACC [QDAF 2020]. 

Recreational harvest is controlled through the minimum legal size and an individual possession limit (n = 5). The Indigenous catch is unknown but is expected to be minor. 

On the basis of the evidence provided above, the East Coast Queensland management unit is classified as a sustainable stock.

Gulf of Carpentaria

Red Emperor in this stock has historically been taken by demersal fish trawl in the Gulf of Carpentaria Developmental Fin Fish Trawl Fishery (GOCDFFTF) and Northern Territory Demersal Fishery (DF). This stock was also exposed to historical fishing from foreign fleets during the 1950s to the 1980s [O’Neill et al. 2011]. 

There are limited estimates of recreational or Indigenous harvest of Red Emperor in the Gulf of Carpentaria, but it is expected to be minor given the offshore nature of the fishery. Recreational catch of Red Emperor in the Northern Territory was estimated to be < 0.5 t in 2018–19 [West et al. 2022]. There has been a small amount of charter catch in Queensland, with catches increasing and averaging 5t from 2006–07 to 2010–11. Catches declined and no charter catch has been reported since 2017–18. The Northern Territory charter catch in the Gulf of Carpentaria has average less than 100 fish per year for the last ten years.

Commercial catches peaked during the 1970s at approximately 30 t and are only slightly higher than the 2008 peak (23 t). The GOCDFFTF is responsible for the majority of the post-2000 Gulf of Carpentaria Red Emperor harvest. However, harvest rates in this fishery declined markedly over the post-2012 period and no Red Emperor was reported from the fishery from 2016–17 to 2019–20. Commercial fishing in the GOCDFFTF resumed from 2020-21 with the fishery registering annual harvests of < 4 t. These catch totals are well below the 21 t Red Emperor TACC set for the fishery. Northern Territory commercial catch of Red Emperor in the Gulf of Carpentaria has ranged from < 0.5 to 7.6 t, at an annual average of 2.9 t, for the last 10 years (2012–13 to 2021–22).

Red Emperor harvests in the GOCDFFTF is managed under a combined 450 t Total Allowable Commercial Catch (TACC). This limit was introduced in 2015 and represented a considerable reduction from the previous combined 1,250 t TACC [O’Neil et al. 2011; Leigh and O’Niell 2016]. For reference and context, fishery independent surveys provided a relative biomass estimate for Red Emperor in the GOCDFFTF [Knuckey et al. 2022]. 

A fishery independent survey was undertaken in 2021 to estimate the relative biomass of key species in the TRF and DF, including Red Emperor. As a result of this work the biomass of Red Emperor in the NT was estimated to be 2,670 t, with a coefficient of variation of 0.17. Within this, the biomass of Red Emperor in the Northern Territory portion of the Gulf of Carpentaria stock was estimated to be 1,127 t [Knuckey and Koopman 2022]. NT commercial harvest in this stock has averaged < 3 t in the last 10 years, which is less than 0.3% of the estimated relative biomass. It is important to note that the survey was designed to obtain a time-series of consistent and robust relative abundance indices that and due to uncertainties around assumptions of catchability, herding and escapement, this one-off estimate of absolute abundance should be used with caution [Knuckey and Koopman 2022]. Regardless, the low level of catch indicates the stock is unlikely to be depleted and the level of fishing mortality is unlikely to result in the stock becoming recruitment impaired.

On the basis of the evidence provided above, Red Emperor in the Gulf of Carpentaria biological stock is classified as a sustainable stock.

Red Emperor biology [McPherson et al. 1992; McPherson and Squire 1992; Newman et al. 2000, 2001; Newman and Dunk 2002; Newman et al. 2010; O'Neill et al. 2011; Sumpter et al. 2022]

Distribution of reported commercial catch of Red Emperor.

Western Australia. Active Vessels data are confidential as there were fewer than three vessels in the Pilbara Fish Trawl Interim Managed Fishery, the Pilbara Trap Managed Fishery and the West Coast Demersal Gillnet and Demersal Longline (Interim) Managed Fishery.

Western Australia – Commercial (Management Methods). Red Emperor forms part of the combined Total Allowable Commercial Catch for other mixed demersal species in the Gascoyne Demersal Scalefish Managed Fishery.

Western Australia – Recreational (Catch). Boat-based recreational catch is from 1 September 2020–31 August 2021. These data are derived from those reported in Ryan et al. 2022.

Western Australia – Recreational (Management Methods). A Recreational Fishing from Boat Licence is required for the use of a powered boat to fish or to transport catch or fishing gear to or from a land-based fishing location.

Western Australia – Indigenous (Management Methods). Subject to application of Section 211 of the Native Title Act 1993 (Cth), and the exemption from a requirement to hold a recreational fishing licence, the non-commercial take by Indigenous fishers is covered by the same arrangements as that for recreational fishing.

Northern Territory — Charter (Management Methods). In the Northern Territory, charter operators are regulated through the same management methods as the recreational sector but are subject to additional limits on license and passenger numbers.

Northern Territory – Indigenous (Management Methods). The Fisheries Act 1988 (NT), specifies that: “Unless expressly provided otherwise, nothing in this Act derogates or limits the right of Aboriginal people who have traditionally used the resources of an area of land or water in a traditional manner to continue to use those resources in that area in that manner.”

Queensland – Commercial (Catch). Queensland commercial and charter data have been sourced from the commercial fisheries logbook program.  Further information is available through the Queensland Fisheries Summary Report (https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/data/queensland-fisheries-summary-report)  

Queensland – Recreational Fishing (Catch). Data based at the whole of Queensland level and derived from statewide recreational fishing surveys. Estimates have been converted to weight (tonnes) using best known conversion multipliers. Conversion factors may display regional or temporal variability. 

Queensland – Indigenous (Management Methods). For more information see: https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing.

Queensland – Commercial (Management Methods). Harvest strategies available at: https://www.daf.qld.gov.au/business-priorities/fisheries/sustainable/harvest-strategy

Commercial catch of Red Emperor - note confidential catch not shown

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