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Spangled Emperor (2023)

Lethrinus nebulosus

  • Corey Wakefield (Department of Primary Industries and Regional Development, Western Australia)
  • Fabian Trinnie (Department of Primary Industries and Regional Development, Western Australia)
  • Marlee Jesson-Kerr (Department of Agriculture and Fisheries, Queensland)
  • Amos Mapleston (Department of Agriculture and Fisheries, Queensland)
  • Julian Hughes (New South Wales Department of Primary Industries)
  • Benjamin Kelly (Department of Industry, Tourism and Trade, Northern Territory)
  • Stephen Newman (Department of Primary Industries and Regional Development, Western Australia)

Date Published: June 2023

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Summary

Spangled Emperor has a wide distribution around Australia. There are eight stocks—defined at either the management unit or jurisdictional level—across WA, the NT, QLD and NSW. In WA three management units are sustainable and one is recovering. The NT jurisdictional stock is sustainable. In QLD one management unit is sustainable and one is undefined. The NSW management unit is negligible.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Stock status Indicators
Northern Territory Northern Australia Negligible

Catch, SAFE assessment

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Stock Structure

Spangled Emperor has a widespread Indo-West Pacific distribution, ranging from the Red Sea, Persian Gulf, and East Africa east to southern Japan in the north, around northern Australia and extending east to Samoa [Carpenter and Allen 1989]. In Australia, Spangled Emperor are found from around Rottnest Island on the lower west coast, across northern Australia to south of Sydney on the east coast [Carpenter and Allen 1989; Carpenter and Niem 2001].

The population structure of Spangled Emperor in Western Australia has been studied by assessing spatial variation in allozymes [Johnson et al. 1993], otolith microchemistry [Moran et al. 1993], tagging and recapture [Moran et al. 1993], DNA micro-satellite markers [Berry et al. 2012], and acoustic telemetry [Pillans et al. 2014]. Individuals generally demonstrate a limited home range of less than three nautical miles [Moran et al. 1993]. Relatively high site fidelity has been shown for at least some individuals in Western Australia and elsewhere [Chateau and Wantiez 2008; Pillans et al. 2014]. Limited mixing of post-settlement individuals is also indicated from an analysis of otolith microchemistry of Spangled Emperor sampled from different sites [Moran et al. 1993].

Genetic studies have demonstrated homogeneous genetic characteristics across broad spatial scales (10–1,500 km) throughout the distribution of Spangled Emperor in Western Australian [Johnson et al. 1993]. Analysis of fine-scale patterns using high resolution micro-satellite markers, however, has found that juveniles exhibit fine-scale genetic autocorrelation, which declines with age [Berry et al. 2012]. This implies both larval cohesion and limited juvenile dispersal prior to maturity, primarily in the vicinity of the Ningaloo Marine Park [Berry et al. 2012]. Hydrodynamic modelling indicated that Spangled Emperor larvae were likely to be transported hundreds of kilometres, easily accounting for the observed gene flow, despite relatively restricted adult dispersal [Berry et al. 2012]. As such, Spangled Emperor are considered to comprise a single biological stock in at least Western Australia. However, there is limited mixing of adult Spangled Emperor. Given the absence of any discrete genetic structure, there is insufficient evidence to suggest revision of current management boundaries. Hence, the current boundaries that designate separate management units are deemed appropriate if adequate levels of adult biomass are maintained, as declines in one stock may have broader implications for the population network given the broader connectivity.

There is a high likelihood that these population characteristics (extensive gene flow, limited adult movement) are shared across each of the jurisdictions. Low genetic subdivision between northwest Western Australia and the Great Barrier Reef suggests gene flow is likely to be high between these regions [Berry et al. 2012]. There is possibly one genetic stock in Australia, however, improved stock delineation work is required in jurisdictions outside Western Australia.

Here, assessment of stock status is presented at the management unit level—West Coast, Gascoyne, Pilbara, Kimberley (Western Australia); Gulf of Carpentaria (Queensland), East Coast (Queensland); and New South Wales; and at the jurisdictional level—Northern Territory.

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Stock Status

Northern Australia

Stock status for Spangled Emperor in the Northern Territory is reported as Negligible due to historically low catches in this jurisdiction, and because the stock has generally not been subject to targeted fishing. During the period 2010–19, Fishing Tour Operators in the Northern Territory have reported small (< 0.1 t) annual catches of Spangled Emperor. The Northern Territory commercial catch during 2017–18 to 2021–22 averaged less than 700 kg per annum, and Spangled Emperor is not a major component of recreational landings. Fishing is unlikely to be having a negative impact on the stock.

On the basis of the evidence provided above, Spangled Emperor in the Northern Territory is classified as a Negligible stock.

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Biology

Spangled Emperor biology [Currey et al. 2013; DAF unpublished data: Marriott et al. 2010, 2011]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Spangled Emperor

31 years: 707 mm FL (WA) 24 years, 810 mm FL and 8.9kg (east coast Queensland/GBR)

3.6 years: 350 mm FL

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Distributions

Distribution of reported commercial catch of Spangled Emperor

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Tables

Fishing methods
Northern Territory
Commercial
Unspecified
Charter
Hook and Line
Recreational
Hook and Line
Indigenous
Various
Management methods
Method Northern Territory
Charter
Limited entry
Passenger restrictions
Commercial
Gear restrictions
Limited entry
Spatial closures
Spatial zoning
Total allowable catch
Recreational
Bag and possession limits
Gear restrictions
Spatial closures
Catch
Northern Territory
Commercial 354.00kg
Indigenous Unknown
Recreational Unknown

Western Australia – Recreational (Catch). Boat-based recreational catch is from 1 September 2020–31 August 2021. These data are derived from those reported in Ryan et al. (2022).

Western Australia – Recreational (Management Methods). A Recreational Fishing from Boat License 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.

Western Australia – Commercial (Catch). Catch is unavailable as there were fewer than three vessels in the Pilbara Fish Trawl Interim Managed Fishery, Pilbara Trap Managed Fishery and West Coast Demersal Gillnet and Demersal Longline (Interim) Managed Fishery.

Western Australia – Active Vessels. Data are confidential as there were fewer than three vessels in the Pilbara Fish Trawl Interim Managed Fishery, Pilbara Trap Managed Fishery and West Coast Demersal Gillnet and Demersal Longline (Interim) Managed Fishery.

Western Australia – Commercial (Management Methods). Spangled Emperor forms part of the combined Total Allowable Commercial Catch for other mixed demersal species in the GDSMF.

Queensland – Recreational Fishing (Catch). Data are based at the whole of Queensland level and derived from state-wide recreational fishing surveys. Where possible, estimates have been converted to weight (tonnes) using best known conversion multipliers. Conversion factors may display regional or temporal variability. In the absence of an adequate conversion factor, data presented as number of fish. 

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  

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

Northern Territory — Charter (Management Methods). In the Northern Territory, charter operators are regulated through the same management methods as the recreational sector but are subject to additional limits on license and passenger numbers.

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.”

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Catch Chart

Commercial catch of Spangled Emperor - note confidential catch not shown

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References

  1.  Moran, M, Edmonds, J, Jenke, J, Cassells, G and Burton, C, 1993, Fisheries biology of emperors (Lethrinidae) in north-west Australian coastal waters, Final Report to the Fisheries Research and Development Corporation (FRDC) on Project No. 89/20, Fisheries Department, Perth, Western Australia. 58p.
  2. Berry, O, England, P, Marriott, RJ, Burridge, CP and Newman SJ 2012, Understanding age-specific dispersal in fishes through hydrodynamic modelling, genetic simulations and microsatellite DNA analysis. Molecular Ecology, 21, 2145–2159, doi:10.1111/j.1365-294X.2012.05520.x.
  3. Carpenter, KE and Allen, GR 1989, FAO Species Catalogue. Emperor Fishes and Large-Eyed Breams of the World (Family Lethrinidae). FAO Fisheries synopsis No. 125, Vol. 9. Rome: FAO, 126 pp.
  4. Carpenter, KE and Niem, VH (eds.) 2001, FAO species identification guide for fishery purposes, The living marine resources of the Western Central Pacific. Volume 5. Bony fishes part 3 (Menidae to Pomacentridae). Rome, FAO, pp. 2791–3380.
  5. Chateau, O and Wantiez, L 2008, Human impacts on residency behaviour of spangled emperor, Lethrinus nebulosus, in a marine protected area, as determined by acoustic telemetry, Journal of the Marine Biological Association of the United Kingdom, 88, 825–829.
  6. Currey, LM, Williams, AJ, Mapstone, BD, Davies CR, Carlos G, Welch DJ, Simpfendorfer, CA, Ballagh, AC, Penny, AL, Grandcourt, EM, Mapleston, A, Wiebkin AS and Bean K 2013, Comparative biology of tropical Lethrinus species (Lethrinidae): challenges for multi-species management. Journal of Fish Biology, 82: 764–788.
  7. DPIRD 2017, North Coast demersal scalefish resource harvest strategy 2017–2021. Version 1.0. Fisheries Management Paper No. 285. Department of Primary Industries and Regional Development, Government of Western Australia, Perth, Australia. 35p.
  8. Gaughan, DJ and Santoro K, (eds.) 2018, Status Reports of the Fisheries and Aquatic Resources of Western Australia 2016/17: The State of the Fisheries, Department of Primary Industries and Regional Development, Western Australia, Perth, Australia. 237p.
  9. Johnson, MS, Hebbert, DR, and Moran, MJ 1993, Genetic analysis of populations of north-western Australian fish species, Australian Journal of Marine and Freshwater Research, 44: 673–685.
  10. Marriott, R, Jackson, G, Lenanton, R, Telfer, C, Lai, E, Stephenson, P, Bruce, C, Adams, D, Norriss, J, and Hall, N, 2012, Biology and stock status of inshore demersal scalefish indicator species in the Gascoyne Coast Bioregion, Fisheries Research Report, No 228, Department of Fisheries, Western Australia.
  11. Marriott, RJ, Adams, DJ, Jarvis NDC, Moran, MJ, Newman SJ, Craine M, 2011, Age-based demographic assessment of fished stocks of spangled emperor, Lethrinus nebulosus in the Gascoyne Bioregion of Western Australia. Fisheries Management and Ecology 18 (2): 89-103.
  12. Marriott, RJ, Jarvis, NDC, Adams, DJ, Gallash, AE, Norriss, J and Newman SJ, 2010, Maturation and sexual ontogeny in the spangled emperor Lethrinus nebulosus. Journal of Fish Biology, 76 (6): 1396–1414. DOI: 10.1111/j.1095-8649.2010.02571.x
  13. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE and Hughes JM, 2021, The Recreational Fisheries Monitoring Program. Survey of recreational fishing in 2017–18, Fisheries final report series 158, NSW Department of Primary Industries, Wollongong.
  14. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE, Hughes, JM, and Taylor, MD 2022, Survey of recreational fishing in NSW, 2019/20. NSW Department of Primary Industries, Nelson Bay, Fisheries Final Report Series No. 161. 80p.
  15. Newman, SJ, Brown, JI, Fairclough, DV, Wise, BS, Bellchambers, LM, Molony, BW, Lenanton, RCJ, Jackson, G, Smith, KA, Gaughan, DJ, Fletcher, WJ, McAuley, RB, and Wakefield, CB 2018, A risk assessment and prioritisation approach to the selection of indicator species for the assessment of multi-species, multi-gear, multi-sector fishery resources, Marine Policy, 88: 11–22.
  16. Pillans, RD, Bearham, D, Boomer, A, Downie, R, Patterson, TA, Thomson, DP and Babcock, RC 2014, Multi-year observations reveal variability in residence of a tropical demersal fish, Lethrinus nebulosus: Implications for spatial management. PLoS ONE, 9(9), e105507.
  17. Queensland Department of Agriculture and Fisheries, 2020, Reef line fishery harvest strategy: 2020–2025, Brisbane, Queensland.
  18. Queensland Department of Agriculture and Fisheries, Unpublished Data 2023, Fisheries Monitoring, State of Queensland, Brisbane.
  19. Ryan KL, Lai EKM, Smallwood CB. 2022. Boat-based recreational fishing in Western Australia 2020/21. Fisheries Research Report No. 327 Department of Primary Industries and Regional Development, Western Australia. 221pp.
  20. Teixeira, D, Janes, R, and Webley, J 2021, 2019/20 Statewide Recreational Fishing Survey Key Results. Project Report. State of Queensland, Brisbane.
  21. Wakefield, C, Trinnie, F, Skepper, C, Boddington, D, Newman, SJ, and Steele, A 2023, North Coast Demersal Resource Status Report 2022. pp. 167–176. In: Gaughan, DJ and Santoro, K (eds.) 2023. Status Reports of the Fisheries and Aquatic Resources of Western Australia 2021/22: The State of the Fisheries. Department of Primary Industries and Regional Development, Western Australia, Perth, Australia.
  22. West, LD, Stark, KE, Murphy, JJ, Lyle, JM and Ochwada-Doyle FA, 2015, Survey of recreational fishing in New South Wales and the ACT, 2013–14, Fisheries final report series 149, NSW Department of Primary Industries, Wollongong.

Downloadable reports

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