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CORAL TROUTS

Plectropomus spp. & Variola spp.

  • Tom Roberts (Department of Agriculture and Fisheries, Queensland)
  • Ashley Williams (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Nic Marton (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Stephen Newman (Department of Fisheries, Western Australia)
  • Thor Saunders (Department of Primary Industry and Resources, Northern Territory)
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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Queensland Coral Reef Fin Fish Fishery CRFFF Sustainable Quantitative Stock Assessment, catch
Queensland Gulf of Carpentaria DFFTF, GOCLF Undefined Catch,
Northern Territory Northern Territory CLF, FTO Sustainable Catch, SAFE  assessment
Commonwealth Torres Strait Finfish Fishery TSFF Sustainable Management strategy evaluation
Western Australia Western Australia GDSMF, NDSMF, PLF, PTMF, PFTIMF, WCDSIMF Sustainable Catch
CLF
Coastal Line Fishery (NT)
CRFFF
Coral Reef Fin Fish Fishery (QLD)
DFFTF
Developmental Fin Fish Trawl Fishery (QLD)
FTO
Fishery Tour Operator (NT)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
GOCLF
Gulf of Carpentaria Line Fishery (QLD)
NDSMF
Northern Demersal Scalefish Managed Fishery (WA)
PLF
Pilbara Line Fishery (WA)
PTMF, PFTIMF
Pilbara Trap Managed Fishery, Pilbara Fish Trawl (Interim) Managed Fishery (WA)
TSFF
Torres Strait Finfish Fishery (CTH)
WCDSIMF
West Coast Demersal Scalefish (Interim) Managed Fishery (WA)
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Stock Structure

The Coral Trout species complex, part of the family Serranidae, is found throughout Australia and is comprised of: Common Coral Trout (Plectropomus leopardus), Barcheek Coral Trout (P. maculatus), Bluespotted Coral Trout (P. laevis), Passionfruit Coral Trout (P. areolatus), Yellow-edge Coronation Trout (Variola louti) and White-edge Coronation Trout (V. albimarginata), with the Bluespotted Coral Trout and Passionfruit Coral Trout not being found in Western Australia and Northern Territory. The biological stock structures of these species are spatially complex1–4 and remain uncertain.

 

Here, assessment of stock status for this multispecies group is presented at the management unit level—Torres Strait Finfish Fishery (Commonwealth); Coral Reef Fin Fish Fishery and Gulf of Carpentaria (Queensland); and at the jurisdictional level—Western Australia and Northern Territory.

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Stock Status

Torres Strait Finfish Fishery

No formal stock assessment has been conducted in the Torres Strait Finfish Fishery (Commonwealth) (TSFF), but a management strategy evaluation (MSE) incorporating a population model using biological parameters from Common Coral Trout (P. leopardus)5,6 explored a range of alternative management options, including four constant annual catch scenarios ranging from 80–170 tonnes (t). Plectropomus leopardus biological parameters were used because it is the most abundant species in the commercial catch of Torres Strait. The biomass7 in 2014 was estimated to be more than 60 per cent of assumed unfished level, and all catch scenarios achieved a biomass of at least 70 per cent of the unfished level, by 2025. Annual catches in the TSFF have declined since 2004, to levels well below the lowest annual catch level simulated in the MSE.

 

The above evidence indicates that the biomass of this management unit stock is unlikely to be recruitment overfished6. The lower level of harvest in recent years is unlikely to cause the management unit to become recruitment overfished6.

 

On the basis of the evidence provided above, the multispecies Torres Strait Finfish Fishery (Commonwealth) management unit is classified as a sustainable stock.

Western Australia

Coral Trout is not a target species in the demersal fisheries of Western Australia, but is landed as by-product. Coral Trout are landed in many of the demersal fisheries of Western Australia. For example, they are a component of the Pilbara Trap Managed Fishery (PTMF), Pilbara Fish Trawl Interim Managed Fishery (PTIMF), Pilbara Line Fishery (PLF) and the Northern Demersal Scalefish Managed Fishery (NDSMF; in the Kimberley region of Western Australia). Coral Trout are therefore assessed on the basis of the status of several indicator species (for example, Red Emperor—Lutjanus sebae and Goldband Snapper—Pristipomoides multidens in the Kimberley region) that represent the inshore demersal suite of species occurring at depths of 30–250 m. The major performance measures for these indicator species are estimates of spawning stock levels. The target level of spawning biomass is 40 per cent of the unfished level. The limit level is 30 per cent of the estimate of initial spawning biomass. As an example, indicator species assessments using an integrated age structured model determined that the spawning biomass levels of each of the indicator species were greater than 40 per cent of the unfished level in the PTMF, PFTIMF and PLF in 20078. Furthermore, the spawning biomass levels of the indicator species were either greater than the target level or between the target level and the threshold level in the NDSMF in 20148. The above evidence indicates that the biomass of this stock is unlikely to be recruitment overfished.

Only small catches of Barcheek Coral Trout and Common Coral Trout are reported, with very small catches of Yellow-edge Coronation Trout and White-edge Coronation Trout8. The total commercial catch of all species within the Coral Trout complex in Western Australia in 2015 was 22 t. The catches of Coral Trout are low and variable throughout their range in Western Australia. Coral Trout are landed by recreational and charter fishers, with the total estimated recreational catch (23 t) being similar to the total landed commercial catch. Given the low level of overall landings (55 t) of all species of Coral Trout, across multiple fisheries in Western Australia, it is unlikely that any one species is recruitment overfished, or that the level of fishing mortality is likely to cause any species in the Coral Trout complex in Western Australia to become recruitment overfished. The above evidence indicates that the biomass of this stock is unlikely to be recruitment overfished, and 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 Coral Trout species group in Western Australia is classified as a sustainable stock.

Northern Territory

Only small catches are reported from the Fishing Tour Operator sector, Coastal Line Fishery, Demersal Fishery and Timor Reef Fishery. Because Coral Trout are only an incidental catch in these fisheries and are rarely caught by recreational fishers9, a semi-quantitative sustainable assessment for fishing effects model9 was used to assess the fishing mortality rate on this species, using data up to 2015. The model results indicated that there is a low risk of Coral Trout being overfished at current levels of harvest, as there is a very low overlap of the fisheries activity and the distribution of Coral Trout in Northern Territory waters. The above evidence indicates that the biomass of this stock is unlikely to be recruitment overfished; and 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 Coral Trout species group in the Northern Territory is classified as a sustainable stock.

Coral Reef Fin Fish Fishery

Common Coral Trout dominates catches in the Coral Reef Fin Fish Fishery (Queensland)10. The most recent stock assessment of Common Coral Trout conducted in 201410 estimated that the biomass in 2012 was 60 per cent of the unfished (1962) level. The stock is not considered to be recruitment overfished.

 

The 2014 stock assessment10 estimated that current catch levels are lower than the estimated maximum sustainable yield for the stock. In 2014, decision rules were introduced for the commercial fishery that set the total allowable commercial catch (TACC) at a maximum economic yield target of 68 per cent of unfished biomass, in order to increase resilience of the stock, and the sustainability of the fishery. Over the past two fishing seasons, the TACC has been reduced by 371 t as a result of applying the decision rules. This level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

 

On the basis of the evidence provided above, the multispecies Coral Reef Fin Fish Fishery (Queensland) management unit is classified as a sustainable stock.

Gulf of Carpentaria

Coral Trout is not a target species in Queensland-managed commercial fisheries in the Gulf of Carpentaria. They are taken as by-product in the Developmental Fin Fish Trawl Fishery (Queensland) and Gulf of Carpentaria Line Fishery (Queensland), but only small catches are reported. Coral Trout is a popular recreational species for Gulf of Carpentaria residents and visiting fishers, but estimates of the recreational catch for Coral Trout in this region are uncertain due to the small sample size in the Gulf of Carpentaria. There is insufficient information available to confidently classify the status of this stock.

 

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

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Biology

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
CORAL TROUTS Plectropomus leopardus: 17 years; ~650 mm FL P. maculatus: 13 years; ~650 mm FL P. laevis: 16 years; ~1150 mm FL P. areolatus: 14 years; ~650 mm FL Variola louti: 7 years;~520 mm FL V. albimarginata: 12 years; ~380 mm FL All species are protogynous hermaphrodites (individuals are born female and later become male). Size at maturity and sex change also vary by location. P. leopardus: female ~280 mm FL, male ~500 mm FL  P. maculatus: female ~300 mm FL, male ~ 440 mm FL P. laevis: female ~450 mm FL, male ~870 mm FL P. areolatus: female ~370 mm FL, male ~550 mm FL V. louti: Unknown V. albimarginata: Unknown

Coral Trout biology11–18

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Distributions

Distribution of reported commercial catch of Coral Trout

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Tables

Fishing methods
Commonwealth Western Australia Northern Territory Queensland
Commercial
Line
Various
Unspecified
Otter Trawl
Indigenous
Spearfishing
Hand Line, Hand Reel or Powered Reels
Recreational
Spearfishing
Hand Line, Hand Reel or Powered Reels
Management methods
Method Commonwealth Western Australia Northern Territory Queensland
Commercial
Catch restrictions
Gear restrictions
Limited entry
Size limit
Spatial closures
Spatial zoning
Temporal closures
Total allowable catch
Total allowable effort
Vessel restrictions
Indigenous
Laws of general application
Spatial closures
Recreational
Bag limits
Gear restrictions
Licence
Limited entry
Passenger restrictions
Possession limit
Size limit
Spatial closures
Spatial zoning
Temporal closures
Active vessels
Commonwealth Western Australia Northern Territory Queensland
2 in TSFF 16 in GDSMF, 8 in NDSMF, 6 in PLF, 37 in WCDSCMF 24, 9 in CLF, 8 in TRF 190 in CRFFF, 1 in DFFTF, 1 in GOCLF
CLF
Coastal Line Fishery (NT)
CRFFF
Coral Reef Fin Fish Fishery (QLD)
DFFTF
Developmental Fin Fish Trawl Fishery (QLD)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
GOCLF
Gulf of Carpentaria Line Fishery (QLD)
NDSMF
Northern Demersal Scalefish Managed Fishery (WA)
PLF
Pilbara Line Fishery (WA)
TRF
Timor Reef Fishery (NT)
TSFF
Torres Strait Finfish Fishery (CTH)
WCDSCMF
West Coast Deep Sea Crustacean Managed Fishery (WA)
Catch
Commonwealth Western Australia Northern Territory Queensland
Commercial 18.01t in TSFF 68.80kg in GDSMF, 3.67t in NDSMF, 319.00kg in PLF, 2.50t in WCDSIMF 200.83kg in CLF, 1.36t in FTO 753.60t in CRFFF, 760.00kg in DFFTF, 37.50kg in GOCLF
Indigenous Unknown Negligible Unknown
Recreational 6.87 t, 16.35 t 2.8 t (2010),0.9 t in FTO (2012) 57 t, 103 000 fish (~105 t) (2013)
CLF
Coastal Line Fishery (NT)
CRFFF
Coral Reef Fin Fish Fishery (QLD)
DFFTF
Developmental Fin Fish Trawl Fishery (QLD)
FTO
Fishery Tour Operator (NT)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
GOCLF
Gulf of Carpentaria Line Fishery (QLD)
NDSMF
Northern Demersal Scalefish Managed Fishery (WA)
PLF
Pilbara Line Fishery (WA)
TSFF
Torres Strait Finfish Fishery (CTH)
WCDSIMF
West Coast Demersal Scalefish (Interim) Managed Fishery (WA)

Commonwealtha Queenslanda Northern Territoryb Western Australiab Recreationalc Indigenousd,e,f

 

 

a Data provided for the Commonwealth and Queensland align with the 2014–15 financial year.

b Data provided for Western Australia and the Northern Territory align with the 2015 calendar year.

c The Australian Government does not manage recreational fishing in Commonwealth waters. Recreational fishing in Commonwealth waters is managed by the state or territory immediately adjacent to those waters, under its management regulations.

d The Australian Government does not manage non-commercial Indigenous fishing in Commonwealth waters (with the exception of the Torres Strait). In general, non-commercial Indigenous fishing in Commonwealth waters is managed by the state 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), the 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.

e Under the Fisheries Act 1994 (Qld), Indigenous fishers in Queensland 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.

f Subject to the defence that applies under 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.

g Western Australia – Commercial (management methods) In Western Australia, different zones within fisheries may have different effort allocations.

h Western Australia – Recreational (Catch) Boat-based recreational catch from 1 May 2013–30 April 2014.

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Catch Chart

Commercial catch of Coral Trout

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Effects of fishing on the marine environment

  • There were no reported interactions with protected species by the Torres Strait Finfish Fishery (Commonwealth) in 2014, or the Coral Reef Fin Fish Fishery (Queensland) (CRFFF) in the 2012–13 fishing season, indicating that the impact of these fisheries on protected species is low.

 

  • Line fishing for Coral Trout is likely to have little direct effect on the marine environment20. However, there is evidence that the removal of predators (including Coral Trout) can lead to an increase in the abundance of their prey species, which is indicative of food web changes20. The impacts of this are unknown.

 

  • During the 2014–15 fishing seasons, the CRFFF reported minimal interactions with protected species. The following species: Barramundi Cod and Humphead Maori Wrasse, were identified, but overall the impact on protected species is low.

 

  • Commercial trawl gear used in the Northern Territory has the potential to impact on the benthic habitat. However, trawl nets in the Northern Territory have been designed to fish off the seabed, reducing interaction with benthic habitats21. The trawl fishery in the Northern Territory comprises a very small fleet and only fishes about seven per cent of the available area21.
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Environmental effects on CORAL TROUTS

  • The most recent Queensland Coral Trout stock assessment10 notes the impact of cyclones on reducing Coral Trout catch rates. A 2010 study22 reported on the effects of three tropical cyclones on the Coral Reef Fin Fish Fishery (Queensland) industry, including a decrease in Coral Trout catch rates of around one-third in regions with the most structural reef damage. The destruction, scouring and displacement of reef habitat were significant and widespread across large areas of the reef. In addition to the structural reef damage, commercial fishers reported reduced catch rates of all species throughout the directly impacted areas22. The analysis identifies depressed catch rates for 12–24 months in affected areas following cyclones.

 

  • Climate change impacts are a concern for coral reef ecosystems. Climate change has been linked to changes in ocean chemistry, and increases in the frequency and extent of coral bleaching events23. These events can also affect the replenishment rates of coral reef fin fish populations, individual growth rates24 and spawning output25,26 and may influence the geographic distribution of coral reef species (for example, latitudinal shifts in distribution).
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References

  1. 1 Bergenius, MA, Begg, GA and Mapstone, BD 2006, The use of otolith morphology to indicate the stock structure of common Coral Trout (Plectropomus leopardus) on the Great Barrier Reef, Australia, Fishery Bulletin, 104: 498–511.
  2. 2 Bergenius, MAJ, Mapstone, BD, Begg, GA and Murchie, CD 2005, The use of otolith chemistry to determine stock structure of three epinepheline serranid coral reef fishes on the Great Barrier Reef, Australia, Fisheries Research, 72:253–270.
  3. 3 Van Herwerden, L, Choat, JH, Dudgeon, CL, Carlos, G, Newman, SJ, Frisch, A and van Oppen, M 2006, Contrasting patterns of genetic structure in two species of the Coral Trout Plectropomus (Serranidae) from east and west Australia: introgressive hybridization or ancestral polymorphisms, Molecular Phylogenetics and Evolution, 41: 420–435.
  4. 4 van Herwerden, L, Choat, JH, Newman, SJ, Lerray, M and Hillesroy, G 2009, Complex patterns of population structure and recruitment of Plectropomus leopardus (Pisces: Epinephelidae) in the Indo-West Pacific: implications for fisheries management, Marine Biology, 156: 1595–1607.
  5. 5 Williams, AJ, Begg, GA, Little, LR, Currey, LM, Ballagh, AC and Murchie, CD 2007, Evaluation of the eastern Torres Strait Reef Line Fishery, Technical report 1, Fishing and Fisheries Research Centre, James Cook University, Townsville.
  6. 6 Marton, N and Skirtun, M 2014, Torres Strait Finfish Fishery, in L Georgeson, I Stobutzki and R Curtotti (eds), Fishery status reports 2013–14, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, 289–299
  7. 7 Williams, AJ, Little, LR and Begg, GA 2011, ‘Balancing indigenous and non-Indigenous commercial objectives in a coral reef finfish fishery’, ICES Journal of Marine Science, vol. 68, no. 5, pp. 834–847.
  8. 8 Newman, SJ, Wakefield, C, Skepper, C, Boddington, D, Blay, N, Jones, R and Dobson, P 2015, North Coast Demersal Fisheries Status Report. pp. 189-206. 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.
  9. 9 West, L.D, Lyle, JM, Matthews, SR, Stark, KE, and Steffe, A.S 2012, Survey of recreational fishing in the Northern Territory, 2009-10. Fishery Report-Department of Resources, Northern Territory Government, (109). 
  10. 10 Leigh, GM, Campbell, AB, Lunow, CP and O’Neill, MF 2014, Stock assessment of the Queensland east coast common coral trout (Plectropomus leopardus) fishery, Queensland Department of Agriculture, Fisheries and Forestry, Brisbane.
  11. 11 Ferreira, BP 1995, Reproduction of the common Coral Trout Plectropomus leopardus (Serranidae: Epinephelinae) from the central and northern Great Barrier Reef, Australia, Bulletin of Marine Science, 56: 653–669.
  12. 12 Heupel, MR, Williams, AJ, Welch, DJ, Davies CR, Adams, S, Carlos, G, and Mapstone, BD 2010, Demography of a large exploited grouper, Plectropomus laevis: Implications for fisheries management, Marine and Freshwater Research, 61: 184–195.
  13. 13 Frisch, AJ, Cameron, DS, Pratchett, MS, Williamson, DH, Williams, AJ, Reynolds, AD, Hoey, AS, Rizzari, JR, Evans, L, Kerrigan, B, Muldoon G, Welch, DJ, and Hobbs, J-PA, 2016, Key aspects of the biology, fisheries and management of Coral grouper, Reviews in Fish Biology and Fisheries, 26: 303–325.
  14. 14 Mapleston, A, Currey, LM, Williams, AJ, Pears, R, Simpfendorfer, CA, Penny, AL, Tobin, A, and Welch D, 2009. Comparative biology of key inter-reefal serranid species on the Great Barrier Reef. Project Milestone Report to the Marine and Tropical Sciences Research Facility, Reef and Rainforest Research Centre Limited, Cairns, 55pp.
  15. 15 Kailola, PJ, Williams, MJ, Stewart, PC, Reichelt, RE, McNee, A and Grieve, C 1993, Australian fisheries resources, Bureau of Resource Sciences and Fisheries Research and Development Corporation, Canberra.
  16. 16 Mapstone, BD 2004, The effects of line fishing on the Great Barrier Reef and evaluations of alternative potential management strategies, Technical report 54, CRC Reef Research Centre, CSIRO Marine Research and Fisheries Research and Development Corporation, Townsville.
  17. 17 Samoilys, MA 1997, Periodicity of spawning aggregations of coral trout Plectropomus leopardus (Pisces: Serranidae) on the northern Great Barrier Reef, Marine Ecology Progress Series, 160: 149–159.
  18. 18 Williams, G, Currey, LM, Begg, GA, Murchie, CD and Ballagh, AC 2008, Population biology of coral trout species in eastern Torres Strait: implications for fisheries management, Continental Shelf Research, 28: 2129–2142.
  19. 19 Webley, JAC, McInnes, K, Teixeira, D, Lawson, A, Quinn, R 2015, Statewide Recreational Fishing Survey 2013–14. Department of Agriculture and Fisheries, Queensland Government.
  20. 20 Great Barrier Reef Management Authority 2009, Great Barrier Reef outlook report 2009, GBRMPA, Townsville.
  21. 21 Mounsey, RP and Ramm, DC 1991, Evaluation of a new design of semi-demersal trawl, Fishery report 25, Northern Territory Department of Primary Industry and Fisheries, Darwin.
  22. 22 Tobin, A, Schlaff, A, Tobin, R, Penny, A, Ayling, T, Ayling, A, Krause, B, Welch, D, Sutton, S, Sawynok, W, Marshall, N, Marshall, P and Maynard, J 2010, Adapting to change: minimising uncertainty about the effects of rapidly-changing environmental conditions on the Queensland Coral Reef Fin Fish Fishery, final report to the Fisheries Research and Development Corporation, project 2008/103, Fishing and Fisheries Research Centre, James Cook University, Townsville.
  23. 23 Hoegh-Guldberg, O, Mumby, PJ, Hooten, AJ, Steneck, RS, Greenfield, P, Gomez, E, Harvell, CD, Sale, PF, Edwards, AJ, Caldeira, K, Knowlton, N, Eakin, CM, Iglesias-Prieto, R, Muthiga, N, Bradbury, RH, Dubi, A and Hatziolos, ME 2007, Coral reefs under rapid climate changes and ocean acidification, Science, 318: 1737–1742.
  24. 24 Hughes, T 2010, Marine and Tropical Sciences Research Facility milestone report for program 2.5i.3, report to the Australian Government Department of the Environment, Water, Heritage and the Arts.
  25. 25 Johnson, JE and Welch, DJ 2010, Marine fisheries management in a changing climate: a review of vulnerability and future options, Reviews in Fisheries Science, 18: 106–124.
  26. 26 Pratchett, MS, Messmer, V, Reynolds, A, Clark, TD, Munday, PL, Tobin, AJ and Hoey, AS 2013, Effects of climate change on reproduction, larval development, and adult health of coral trout (Plectropomus spp.), James Cook University, Townsville.

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