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Redspot Emperor is found throughout tropical Australia in both coastal and offshore habitats. Stocks In NT and WA are classified as sustainable, while stocks found on the east coast of QLD and in the Gulf of Carpentaria are undefined. 

Photo credit: Matthew Dorter

Redspot Emperor is a widespread Indo-Pacific species, found throughout tropical Australia in both coastal and offshore habitats. This species inhabits northern Australia, with its range extending from approximately Gladstone, Queensland in the east, to Port Headland Western Australia, in the west [Carpenter and Allen 1989].

There is no information on population connectivity for this species in Australian waters and subsequently, this species has been assessed at the jurisdictional level for the Northern Territory and Western Australia. In Queensland, geographic separation caused by Torres Strait most likely results in limited movement between the Queensland east coast and the Queensland side of the Gulf of Carpentaria, consequently, this species has been assessed as two management units in this state.

Here, assessment of stock status is presented at the jurisdictional level–Western Australia and Northern Territory, and the management unit level–Gulf of Carpentaria Queensland and East Coast.

Western Australia

The majority of the commercial catch of Redspot Emperor in WA is landed in the Pilbara Fish Trawl (Interim) Managed Fishery. They have also been landed in small quantities in the Northern Demersal Scalefish Managed Fishery, and the Pilbara Trap Managed Fishery. Redspot Emperor are assessed on the basis of the status of several indicator species (including, for example, Red Emperor, Rankin Cod, and Bluespotted Emperor in the Pilbara region, and Red Emperor and Goldband Snapper in the Kimberley region) across the North Coast Demersal Resource (NCDR) that represents the entire inshore demersal suite of species occurring at depths of 30–250 m [Newman et al. 2018]. The indicator species in the Pilbara and Kimberley have been classified as sustainable [Wakefield et al. 2023]. The level of risk associated with the sustainability of Redspot Emperor in the NCDR is assessed as low. This assessment of Redspot Emperor is also supported by the results of a data-limited Catch-MSY assessment, where recent catches are compared to model predictions for maximum sustainable yield (MSY).

The total catch of Redspot Emperor across WA over the last 10 years (2013–22) has ranged from 19–67 t, with a mean annual catch of 34 t. This is a decline from the average catches across the previous 10 years of 53 t. Recreational and charter catches are relatively low compared to the commercial catch, in the past 10 years where reliable catch estimates are available, their contribution of the total catch has averaged less than 1% [Ryan et al. 2022]. Analyses using a Catch-MSY model applied to data on annual catches for this species (1995–2022), indicated that at the beginning of this time period, annual catches were around the median estimate of the model prediction for maximum sustainable yield (MSY). Catches then increased to above the upper 95% CI for MSY in the period from 2001–06, before declining below the lower 95% CI in the period form 2008–17, after which catches then increased to fluctuate around MSY. The above trends are consistent with the predicted values for biomass declining below BMSY (in 2004), remaining below BMSY until 2013, then increasing above BMSY from 2014 onwards, with predicted fishing mortality remaining below FMSY since 2014. However, it is important to recognise that Catch-MSY is a data-limited technique with strong assumptions, dependent on user inputs. For this assessment, these included specified ranges for initial depletion (0.4–0.8), based on likely catch domestically and foreign fleets prior to the start of the time series, final depletion (0.15–0.7), based on recent catches relative to maximum recorded annual catch and the non-targeted nature of commercial fishing for this species, and low resilience (r=0.1–0.6, consistent with species longevity, of approximately 20 years in QLD). Given the relatively low levels of overall landings of Redspot Emperor across multiple fisheries in Western Australia, recent catches of this species remaining within the predicted MSY range, and the status of the indicator species for the NCDR, it is considered unlikely that the biomass of Redspot Emperor in Western Australia is depleted and recruitment is unlikely to be impaired. Furthermore, the level of fishing mortality is unlikely to result in the stock becoming recruitment impaired.

On the basis of the evidence provided above, Redspot Emperor in WA is classified as a sustainable stock. 

Redspot Emperor biology [Currey et al. 2009; Currey et al. 2013; Grandcourt 2002; Johnson unpublished; Mobiha 1991]

Distribution of reported commercial catch of Redspot Emperor – confidential catch is not shown

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

Queensland – Recreational Fishing (Catch). Data with high uncertainty (Residual Error greater than 50 %) has been excluded and listed as unknown. More information available at: https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/monitoring-reporting/statewide-recreational-fishing-surveys

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

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

Western Australia – Recreational (catch). Boat-based recreational catch between 1 September 2020 and 31 August 2021 from Ryan et al. [2022]. Please note that catches of Blue Threadfin are underestimates as shore-based and boat-based fishers that only operated in freshwater were out of scope of the survey.

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.

Commercial catch of Redspot Emperor - note confidential catch not shown

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