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Black Jewfish

Protonibea diacanthus

  • Thor Saunders (Department of Primary Industry and Resources, Northern Territory)
  • Anthony Roelofs (Department of Agriculture and Fisheries, Queensland)
  • Stephen Newman (Department of Fisheries, Western Australia)
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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Queensland Gulf of Carpentaria GOCIFFF Undefined Catch
Northern Territory Northern Territory BF, CLF, DF, FTO, ONLF, TRF Overfished Biomass, egg production
Queensland Queensland East Coast ECIFFF Undefined Catch
Western Australia Western Australia KGBMF, PLF, WANCSF, PTMF, PFTIMF Sustainable Catch
BF
Barramundi Fishery (NT)
CLF
Coastal Line Fishery (NT)
DF
Demersal Fishery (NT)
ECIFFF
East Coast Inshore Fin Fish Fishery (QLD)
FTO
Fishery Tour Operator (NT)
GOCIFFF
Gulf of Carpentaria Inshore Fin Fish Fishery (QLD)
KGBMF
Kimberley Gillnet and Barramundi ManagedFishery (WA)
ONLF
Offshore Net and Line Fishery (NT)
PLF
Pilbara Line Fishery (WA)
TRF
Timor Reef Fishery (NT)
WANCSF, PTMF, PFTIMF
WA North Coast Shark Fishery, Pilbara Trap Managed Fishery, Pilbara Fish Trawl (Interim) Managed Fishery (WA)
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Stock Structure

Black Jewfish is a widespread Indo-Pacific species found from the Pilbara and Kimberley regions in Western Australia, across Northern Australia, to the east coast of Queensland. The stock structure for this species has been investigated in the north western part of its range from the western Gulf of Carpentaria to its southern extent along the west Australian coastline1. The results indicated that separate stocks exist at the scale of 10s of km1.

However, given the recent nature of these findings, here assessment of stock status is presented at the jurisdictional level—Western Australia, Northern Territory; and at the management unit level—Gulf of Carpentaria (Queensland) and Queensland east coast.

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Stock Status

Western Australia

Black Jewfish are not a target species in the Kimberley Gillnet and Barramundi Managed Fishery of Western Australia, but are landed in small quantities as by-product2. They have also been landed in very small quantities as by-product in the Pilbara Fish Trawl Interim Managed Fishery and the Pilbara Line Fishery. The total commercial catch in Western Australia in 2015 was approximately 1 tonne (t). Black Jewfish catches have only been reported from a small area of their range in Western Australia. They are landed by charter fishers, primarily in the Kimberley region of Western Australia, in small quantities. Given the low level of take, the biomass of Black Jewfish in Western Australia is unlikely to be recruitment overfished and the current fishing pressure is unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, Black Jewfish in Western Australia is classified as a sustainable stock.

Northern Territory

The most recent assessment3 estimates that the biomass and egg production was 28 per cent of unfished levels (1973). The model used was an update of the 2011 Stock Reduction Analysis model4 including data up until 2014. The outputs indicated that there was a high probability (98 per cent) that Black Jewfish stocks have been overfished and that overfishing is still occurring (80 per cent). Given the recent new information on the stock structure of this species, it is likely that the assessment incorporates several populations. As the model is driven by the populations that receive the highest harvest rates in the Northern Territory the assigned status can be assumed to be representative of the highest level of exploitation that occurs on any population. The immediate area of concern is in waters around Darwin where most of the fishing pressure occurs3. The fisheries accessing these exploited stocks are those that operate inshore including the Coastal Line Fishery, Barramundi Fishery, fishing tour operators and recreational fishers. Black Jewfish have also been shown to be highly susceptible to barotrauma when caught in waters deeper than ten metres5,6. Management in the form of catch limits and area closures have been put in place to reduce harvest rates by the necessary 20 per cent to allow for the biomass of Black Jewfish stocks to recover4. The stock is considered to be recruitment overfished. This reduction in fishing pressure is expected to allow the stock to recover from its recruitment overfished state; however measurable improvements in biomass are yet to be detected.

On the basis of the evidence provided above, Black Jewfish in the Northern Territory is classified as an overfished stock.

Gulf of Carpentaria

In the Gulf of Carpentaria (Queensland) management unit, Black Jewfish are taken by commercial net fishers and recreational anglers. Commercial catches of Black Jewfish in the Queensland Gulf of Carpentaria Inshore Fin Fish Fishery have decreased from a reported historical high of 33 t in 1990 to less than 0.5 t since 20067. However, specific reporting of Black Jewfish commercial harvest ceased in 2006, and catches reported as ‘Jewfish—Other’ have averaged 6 t per year since this change; Black Jewfish are likely the major component of this harvest. From 1999–2000, there was a distinct lack of large mature fish found in the north Cape York region8. The overall downward trend in catches and the reduced spawning biomass, combined with the vulnerable biology of Black Jewfish (late maturing, aggregating to spawn), resulted in a 2-year ban on fishing for Black Jewfish in key aggregation areas. In 2002, Queensland prohibited the harvest of Black Jewfish in the north Cape York region (north of Crab Island)7. No studies have been undertaken to measure recovery in this region or the overall biomass of Black Jewfish in the Queensland part of the Gulf of Carpentaria.

There are no reliable estimates of recreational harvest for Black Jewfish in the Queensland Gulf of Carpentaria7, but it is known as a popular recreational species in the region. The Queensland legal size limit (600 mm total length) in the Gulf of Carpentaria is well below the reported age of first maturity for females (850–900 mm total length) and may not be effective in protecting spawning females from fishing. A conservative possession limit (two fish) reduces recreational fishing pressure on the stock. There is insufficient information available to confidently classify the status of the stock.

On the basis of the evidence provided above, the Gulf of Carpentaria (Queensland) management unit is classified as an undefined stock.

Queensland East Coast

Black Jewfish are taken by commercial net fishers and recreational anglers on the Queensland east coast. The East Coast Inshore Fin Fish Fishery (Queensland) contributes minimal quantities (5-year average of around 2 t per year) to the overall Queensland east coast harvest. There are no reliable estimates of recreational harvest9. The legal size limit (750 mm total length) is below the reported age of first maturity for females and may not be effective in protecting spawning females from fishing. A conservative possession limit (two fish) reduces recreational fishing pressure on the stock. There is insufficient information available to confidently classify the status of the stock.

On the basis of the evidence provided above, the Queensland east coast management unit is classified as an undefined stock.

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Biology

Black Jewfish biology6,8

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Black Jewfish 15 years; 1 500 mm TL, 30 kg Northern Territory: 890 mm TL (2 years)
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Distributions

Distribution of reported commercial catch of Black Jewfish

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Tables

Fishing methods
Western Australia Northern Territory Queensland
Commercial
Various
Line
Gillnet
Otter Trawl
Unspecified
Pots and Traps
Recreational
Hand Line, Hand Reel or Powered Reels
Spearfishing
Indigenous
Hand Line, Hand Reel or Powered Reels
Management methods
Method Western Australia Northern Territory Queensland
Commercial
Catch limits
Gear restrictions
Limited entry
Size limit
Spatial closures
Spatial zoning
Temporal closures
Vessel restrictions
Indigenous
Gear restrictions
Recreational
Bag limits
Gear restrictions
Licence
Limited entry
Passenger restrictions
Possession limit
Size limit
Spatial closures
Spatial zoning
Active vessels
Western Australia Northern Territory Queensland
4 in KGBMF, 6 in PLF 14 in BF, 9 in CLF, 9 in DF, 10 in ONLF, 8 in TRF 7 in ECIFFF, 2 in GOCIFFF
BF
Barramundi Fishery (NT)
CLF
Coastal Line Fishery (NT)
DF
Demersal Fishery (NT)
ECIFFF
East Coast Inshore Fin Fish Fishery (QLD)
GOCIFFF
Gulf of Carpentaria Inshore Fin Fish Fishery (QLD)
KGBMF
Kimberley Gillnet and Barramundi ManagedFishery (WA)
ONLF
Offshore Net and Line Fishery (NT)
PLF
Pilbara Line Fishery (WA)
TRF
Timor Reef Fishery (NT)
Catch
Western Australia Northern Territory Queensland
Commercial 1.38t in KGBMF, 15.00kg in PLF, 396.50kg in WANCSF, PTMF, PFTIMF 3.11t in BF, 173.18t in CLF, 11.25t in DF, 28.12t in FTO, 77.00kg in ONLF, 579.00kg in TRF 1.92t in ECIFFF, 43.20kg in GOCIFFF
Indigenous Unknown Unknown Unknown
Recreational <0.5 t, 1.74 t 28 t in FTO, 75 t (in 2010) Unknown
BF
Barramundi Fishery (NT)
CLF
Coastal Line Fishery (NT)
DF
Demersal Fishery (NT)
ECIFFF
East Coast Inshore Fin Fish Fishery (QLD)
FTO
Fishery Tour Operator (NT)
GOCIFFF
Gulf of Carpentaria Inshore Fin Fish Fishery (QLD)
KGBMF
Kimberley Gillnet and Barramundi ManagedFishery (WA)
ONLF
Offshore Net and Line Fishery (NT)
PLF
Pilbara Line Fishery (WA)
TRF
Timor Reef Fishery (NT)
WANCSF, PTMF, PFTIMF
WA North Coast Shark Fishery, Pilbara Trap Managed Fishery, Pilbara Fish Trawl (Interim) Managed Fishery (WA)

a Queensland – Indigenous In Queensland, under the Fisheries Act 1994 (Qld), Indigenous fishers are able to use prescribed traditional and non-commercial fishing apparatus in waters open to fishing. Size and possession limits and seasonal closures do not apply to Indigenous fishers. Further exemptions to fishery regulations may be applied for through permits.
b Western Australia – Recreational (catch) Boat-based recreational catch from 1 May 2013–30 April 2014.

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Catch Chart

Commercial catch of Black Jewfish - note confidential catch not shown

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Effects of fishing on the marine environment

  • Black Jewfish are mainly targeted by fishers in all sectors using handlines and rods. Beyond the removal of target and a small proportion of bycatch species, there is little evidence to suggest that this gear significantly impacts on benthic or pelagic ecological communities.
  • In Queensland, coastal river and estuary set gillnets have been shown to have minimal impact on the environment and are quite selective in their harvest10. Bycatch is generally low when compared to the harvest of the target species.
  • Commercial trawl gear used in waters across northern Australia has the potential to impact on the benthic habitat. However, finfish trawl nets have been designed to fish above the seabed, reducing interaction with benthic habitats11. Additionally, the trawl fishery across northern Australian waters comprises a very small fleet and only fishes approximately seven per cent of the available area11.
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Environmental effects on Black Jewfish

  • The impact of environmental factors on Black Jewfish is largely unknown. However, juveniles mainly inhabit coastal estuaries and bays, making these phases of their lifecycle sensitive to ocean current strength and direction, rainfall and river flow and water temperature, salinity and acidity3.
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References

  1. 1 Saunders, TM, Welch, D, Barton, D, Crook, D, Dudgeon, C, Hearnden, M, Maher, S, Ovenden, J, Taillebois, L, Taylor J 2016, Optimising the management of tropical coastal reef fish through the development of Indigenous capability. FRDC final report 2013/017.
  2. 2 Brown, JI, Newman, SJ, Mitsopoulos, G, Skepper, C, Thomson, A and Wallis, D 2015, North Coast Nearshore and Estuarine Fishery Status Report. pp. 182-188. In: Fletcher, W.J. and Santoro, K. (eds.). Status Reports of the Fisheries and Aquatic Resources of Western Australia 2014/15: The State of the Fisheries. Department of Fisheries, Western Australia, Perth, Australia. 353p.
  3. 3 Northern Territory Government 2016, Fishery Status Reports 2015, Northern Territory Government Department of Primary Industry and Resources, Fishery report 115.
  4. 4 Grubert, MA, Saunders, TM, Martin, JM, Lee, HS and Walters, CJ 2013, Stock Assessments of Selected Northern Territory Fishes, Fishery report no. 110, Northern Territory Fisheries.
  5. 5 Phelan, M 2008, Assessment of the implications of target fishing on Black Jewfish (Protonibea diacanthus) aggregations in the Northern Territory, Fisheries Research and Development Corporation project 2004/004, fishery report 91, Northern Territory Fisheries.
  6. 6 Welch, DJ, Robins, J, Saunders, T, Courtney, T, Harry, A, Lawson, E, Moore, BR, Tobin, A, Turnbull, C, Vance, D and Williams, AJ 2014, Implications of climate change impacts on fisheries resources of northern Australia. Part 2: Species profiles, final report to the Fisheries Research and Development Corporation, project 2010/565, James Cook University, Townsville.
  7. 7 Roelofs, AJ 2003, Ecological Assessment of the Gulf of Carpentaria Inshore Finfish Fishery - A report to Environment Australia on the sustainable management of a multi-species tropical gillnet fishery, Department of Primary Industries and Fisheries, Brisbane.
  8. 8 Phelan, MJ 2002, Fishery biology and management of the Black Jewfish Protonibea squamosa (Sciaenidiae) aggregations near Injinoo community, Far Northern Cape York. Stage 1: Initial characterisation of the aggregations and associated fishery, Fisheries Research and Development Corporation project 98/135, Department of Primary Industries, Queensland and Balkanu Cape York Development Corporation, Cairns.
  9. 9 Webley, J, McInnes, K, Teixeira, D, Lawson, A, and Quinn, R 2015, Statewide Recreational Fishing Survey 2013-14, Queensland Department of Agriculture and Fisheries, Brisbane.
  10. 10 Halliday, IA, Ley, JA, Tobin, A, Garrett, R, Gribble, NA, and Mayer, DG 2001, The effects of net fishing: addressing biodiversity and bycatch issues in Queensland inshore waters, Fishieries Research and Development Corporation project 97/206, Department of Primary Industries, Queensland.
  11. 11 Mounsey, RP and Ramm, DC 1991, Evaluation of a new design of semi-demersal trawl, Northern Territory Department of Primary Industry and Fisheries, Darwin.

Archived reports

Click the links below to view reports from other years for this fish.