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Redspot King Prawn occurs throughout the tropical Indo-West Pacific, including northern Australia. The species' biological stock structure is uncertain, and this assessment is consequently presented at the management unit level—East Coast QLD, Northern Australia and WA. The East Coast QLD and the Northern Australia stocks are classified as undefined and the WA stock is negligible due to no history of targeted fishing. 

The Redspot King Prawn has an Indo-West Pacific and tropical Australian distribution from Exmouth Gulf in the west across northern Australia to the Gulf of Carpentaria and Torres Strait and down the east coast to approximately 22⁰S.

Biological Stock Structure of Redspot King Prawn is uncertain. The Northern Australia stock is fished by the Northern Prawn Fishery (Commonwealth) and the Torres Strait Prawn Fishery. The East Coast Queensland stock is taken along the coast of Queensland by the East Coast Otter Trawl Fishery. The Western Australia stock is taken in very low quantities in the Exmouth and North Coast prawn fisheries.

Here, assessment of stock status is presented at the management unit level—East Coast Queensland (Queensland), Northern Australia (Commonwealth); and the jurisdictional level—Western Australia.

East Coast Queensland

The Redspot King Prawn is targeted and retained in the Queensland East Coast Otter Trawl Fishery (ECOTF). The species is typically retained in smaller quantities across the central and northern ECOTF management regions [Queensland Department of Agriculture and Fisheries 2021a, b]. Red Spot King Prawn catches peaked in 2003–04 at 584 tonnes (t) and 8,714 effort days. Catch and effort levels have declined since this peak, reflecting a more general decline in the number of operations retaining Redspot King Prawns. Nominal catch rates over the last 10 years have been variable with an average of 186 t and 3,035 effort days reported from the fishery over the period between 2012–13 and 2021–22. For reference, the fishery retained almost 172 t of Red Spot King Prawns in the 2021–22 season across 2,035 days fished.  

The outputs of a recent East Coast Queensland Redspot King Prawn stock assessment were inconclusive in terms of determining overall biomass levels and the status of the stock [Fox et al. 2023]. Many of the 24 scenarios tested were unstable and only 9 converged, giving a broad range of biomass estimates from 27% to 116% of unfished levels (1968). Due to this uncertainty, model variability and difficulties quantifying rates of recruitment, the stock assessment determined that a reliable estimate of MSY could not be achieved for this stock at this point in time [Fox et al. 2023]. Similarly, as several of the stock assessment scenarios indicated biomass was near 20%, it cannot be confidently stated that the stock is above the limit reference point [Fox et al. 2023].  

Of note the recent assessment refined and improved the spatial scale of the assessment. As a result of these changes, the 2023 stock assessment is considered to be more representative of the catch and effort for this species within Queensland waters when compared to a previous assessment [Wang 2015]. The above evidence suggests that although there are no current concerns for this stock, biomass and recruitment are considered too uncertain to use for status determination.

Since 2021, the ECOTF has been managed through five regional management areas, all with corresponding harvest strategies. Redspot King Prawns are primarily harvested in the central trawl fishery and are a Tier 2 species in the Trawl fishery (central region) harvest strategy: 2021–2026. Under this strategy, no management action is required providing catch of Redspot King Prawns remains between 100 and 300 t [Queensland Department of Agriculture and Fisheries 2021a]. Biophysical modelling research estimates found that a large proportion of the Redspot King Prawn biomass (62%) within the Great Barrier Reef Marine Park (GBRMP) is unavailable to trawl fishing [Pitcher 2013].

An ecological risk assessment based on 2009 effort levels found that there was a low risk of Redspot King Prawn being overfished in the Great Barrier Reef Marine Park [Pears et al. 2012]. Since 2009–10, total effort for Redspot King Prawns (measured as nominal effort days) has decreased and remained stable across the fishing area with an average of 3,206 effort days per year. Most of this effort is restricted to the central region in the ECOTF. However, changes in environmental conditions (such as sea surface temperatures or rainfall) could increase natural mortality which may affect target reference points used for managing fishing effort.  The above evidence indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

The above evidence suggests that although the current nominal catch and effort are low, in line with the recent stock assessment and based on the lack of alternative recent information, further evidence is required to confidently assess the status of this stock.

On the basis of the evidence provided, the East Coast Queensland Redspot King Prawn stock is classified as undefined stock.

Redspot King Prawn biology [Holthuis 1980; Dredge 1990; Kailola et al. 1993]

Distribution of reported Commercial Catch of Redspot King Prawn.

Commonwealth – Indigenous (Management Methods). The Australian government does not manage non-commercial Indigenous fishing (with the exception of the Torres Strait). In general, non-commercial Indigenous fishing in Commonwealth waters is managed by the states or territory immediately adjacent to those waters. In the Torres Strait both commercial and non-commercial Indigenous fishing is managed by the Torres Strait Protected Zone Joint Authority (PZJA) through the Australian Fisheries Management Authority (Commonwealth), Department of Agriculture Fisheries and Forestry (Queensland) and the Torres Strait Regional Authority. The PZJA also manages non-Indigenous commercial fishing in the Torres Strait.

Commonwealth – Recreational (Fishing Methods). The Australian government does not manage recreational fishing. Recreational fishing in Commonwealth waters is managed by the states or territory immediately adjacent to those waters, under their management regulations.

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

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

Commercial catch of Redspot King Prawn - note confidential catch not shown

1. Dredge, MCL 1990, Movement, Growth and Natural Mortality Rate of the Red Spot King Prawn, Penaeus longistylus Kubo , from the Great Barrier Reef Lagoon. Aust. J. Mar. Freshwater Research, 41, 399–410.
2. Holthuis, LB 1980, FAO Species Catalogue. Vol. 1. Shrimps and prawns of the world. An annotated catalogue of species of interest to fisheries, FAO Fish. Synop, 125(1):271 p. Rome: FAO.
3. Kailola, PJ, Williams, MJ, Stewart, PC, Reichhelt, RE, McNee, A and Grieve, C 1993, Australian Fisheries Resources. Bureau of Resource Sciences and the Fisheries Research and Development Corporation.
4. Pears, RJ, Morison, AK, Jebreen, EJ, Dunning, MC, Pitcher, CR, Courtney, AJ, Houlden, B and Jacobsen, IP 2012, Ecological risk assessment of the East Coast Otter Trawl Fishery in the Great Barrier Reef Marine Park: Technical report, Great Barrier Reef Marine Park Authority, Townsville.
5. Pitcher, CR 2013, Quantitative indicators of environmental sustainability risk for a tropical shelf trawl fishery. Fisheries Research, 151, 136-147.
6. Queensland Department of Agriculture and Fisheries 2021a, Trawl fishery (central region) harvest strategy: 2021–2026.
7. Queensland Department of Agriculture and Fisheries 2021a, Trawl fishery (northern region) harvest strategy: 2021–2026.
8. Wang, N 2015, Sustainability and optimality in fisheries management, PhD Thesis, University of Queensland.