Eastern King Prawn Melicertus plebejus​

Andrew Prossera and Faith Doyleb

Eastern King Prawn

Table 1: Stock status determination for Eastern King Prawn


New South Wales, Queensland


Eastern Australian


Stock status



Biomass; catch, effort and CPUE relative to MSY reference points; fishery-independent index of recruit abundance

CPUE = catch per unit effort; ECOTF = East Coast Otter Trawl Fishery (Queensland); EGF = Estuary General Fishery (New South Wales); EPTF = Estuary Prawn Trawl Fishery (New South Wales); MSY = maximum sustainable yield; OTF-PS = Ocean Trawl Fishery–Prawn Sector (New South Wales)

Stock Structure

Eastern King Prawn (Melicertus plebejus) is endemic to Australia. It is one of two Australian species (the other being Western King Prawn: M. latisulcatus) recognised by the standard fish name ‘King Prawn’1. Eastern King Prawns are harvested in Queensland and New South Wales fisheries and are considered a single multi-jurisdictional biological stock2,3. There are two contiguous management units for the stock: one from 22 to 28°S in Queensland, and another along the whole New South Wales coast (28 to 37.5°S). A comprehensive stock assessment of the eastern Australian biological stock has recently been completed3,4. Status determination is made on the basis of the single biological stock.

Stock Status

Eastern Australian biological stock

The most recent quantitative stock assessment undertaken on the biological stock estimated that the biomass in 2010 was 60–80 per cent of 1958 levels3. Maximum sustainable yield (MSY) was estimated at 3100 tonnes (t) (95 per cent confidence interval: 2454 to 3612 t)4. The 2013 catch was 3355 t (2786 t in Queensland, 569 t in New South Wales), which is above the mean estimate of MSY, but below the 95 per cent confidence interval of the estimate (3612 t). The average catch from 2011 to 2013 was 2937 t, which is below the mean estimate of MSY. For the Queensland component of the stock, standardised catch rates were mostly above MSY reference points between 2009 and 20135, indicating that the level of biomass was sufficient to sustain catches at MSY. For the New South Wales component of the stock, median nominal commercial catch rates were relatively stable between 2009 and 2013, and slightly greater than catch rates between 2004 and 20086. Fishery-independent surveys of recruit abundance show variable recruitment to the fishery. The above evidence indicates that the stock is unlikely to be recruitment overfished.

The most recent quantitative stock assessment estimated effort (E) at MSY (EMSY), standardised to the number of boat-days in 2010, as 38 002 boat-days (95 per cent confidence interval: 27 035 to 50 754 boat-days), assuming no increase in fishing power or costs. An alternative estimate of 28 300 boat-days (95 per cent confidence interval: 20 110 to 37 663 boat-days) accounts for a 3 per cent per year increase in fishing power and costs from 2010 levels4. Effort in 2013 was 19 619 boat-days (13 277 boat-days in Queensland5, 6342 boat-days in New South Wales6), which was well below both estimates of EMSY and the peak effort of around 30 000 boat-days in 2000, but similar to levels in 2010. The decline in effort since 2000 has been offset by increases in fishing power7, resulting in increased catch rates and recent record harvests in Queensland. The number of boats accessing the fishery has substantially declined in Queensland and New South Wales since 2010, probably as a result of economic factors3. The above evidence indicates that the current level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

Table 2: Eastern King Prawn biology8-10

Longevity and maximum size

<3 years; males 52 mm CL, females 73 mm CL

Maturity (50%)

Females 42 mm CL

CL = carapace length

Figure 1: Distribution of reported commercial catch of Eastern King Prawn in Australian waters, 2013 (calendar year)

Figure 1: Distribution of reported commercial catch of Eastern King Prawn in Australian waters, 2013 (calendar year)

Table 3: Main features and statistics for Eastern King Prawn fisheries in Australia, 2013 (calendar year)  


New South Wales


Fishing methods


Otter trawl

Beam trawl

Set pocket netting


Scoop netting




Management methods


Limited entry

Vessel restrictions

Effort limits

Temporal closures

Spatial closures

Gear restrictions


Recreational fishing licence

Bag limits

Possession limits


Section 37(1)(c1), Aboriginal cultural fishing authority

Active vessels

56 in EGF

15 in EPTF

79 in OTF-PS

148 in ECOTF



29 t in EGF

14 t in EPTF

526 t in OTF-PS

2786 t in ECOTF


<110 t11








ECOTF = East Coast Otter Trawl Fishery (Queensland); EGF = Estuary General Fishery (New South Wales); EPTF = Estuary Prawn Trawl Fishery (New South Wales); OTF-PS = Ocean Trawl Fishery–Prawn Sector (New South Wales)

a The Aboriginal cultural fishing authority is the authority that Indigenous persons can apply to to take catches outside the recreational limits under the New South Wales Fisheries Management Act 1994, section 37(1)(c1) (Aboriginal cultural fishing authority).

a) Commercial catch of Eastern King Prawn in Australian waters, 2000–10 (calendar year)

Figure 2: Commercial catch of Eastern King Prawn in Australian waters from 1988 to 2013 (calendar years)

Effects of fishing on the marine environment
  • Trawling involves interactions with the benthic environment12, but can only occur over sandy or muddy substrates. Recent research shows that trawling in Queensland has no significant effect on biodiversity or distribution patterns of benthic species13. In Queensland, although trawling is permitted in 34 per cent of the area inside the Great Barrier Reef Marine Park5, it only occurs in suitable areas within the permitted area and poses only an intermediate risk of overfishing species assemblages14. South of the Great Barrier Reef Marine Park, trawling occurs in 10 per cent of the available area15.
  • Improvements in technology, and the mandatory uptake of bycatch reduction and turtle excluder devices, combined with lower numbers of boats accessing the fishery, are likely to have reduced the overall amount of bycatch in the fishery16–20. Interactions with species of conservation interest, including turtles, sea snakes and large elasmobranchs, have also been reduced18. A reduction in bycatch per trawl probably improves the survival of discards and the quality of retained product19.

Environmental effects on Eastern King Prawn
  • Extreme weather events associated with a strong La Niña episode21 in 2011 may have influenced recruitment patterns and access to fishing grounds, resulting in depressed catches of Eastern King Prawn (Figure 2).
  • Climate change is likely to have a significant long-term effect on the distribution of this species. Under a scenario of increasing sea surface temperatures, the distribution of Eastern King Prawn may shift southwards, potentially affecting recruitment and the timing of migration22,23. A study of Moreton Bay24 indicated that recruitment in the Eastern King Prawn fishery tends to decline in years associated with warmer winters, suggesting that recruitment is likely to decline in south-east Queensland as coastal water temperatures rise. Destruction of seagrass beds and alteration of water flows in estuaries could affect the area of nursery grounds available to recruiting prawns, and the size of the biological stock available for capture23.

Department of Agriculture, Fisheries and Forestry, Queensland
b Department of Primary Industries, New South Wales