*

Redthroat Emperor (2018)

Lethrinus miniatus

  • Luke Albury (Department of Agriculture and Fisheries, Queensland)
  • David Fairclough (Department of Primary Industries and Regional Development, Western Australia)

You are currently viewing a report filtered by jurisdiction. View the full report.

Toggle content

Summary

Redthroat Emperor is fished in WA and the east coast of QLD. The stock in QLD is sustainable while the WA stock is classified as recovering.

Toggle content

Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Western Australia Western Australia GDSMF, PTMF, WCDGDLIMF, WCDSIMF Recovering Catch, effort
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
PTMF
Pilbara Trap Managed Fishery (WA)
WCDGDLIMF
West Coast Demersal Gillnet and Demersal Longline (Interim) Managed Fishery (WA)
WCDSIMF
West Coast Demersal Scalefish (Interim) Managed Fishery (WA)
Toggle content

Stock Structure

Genetic analysis indicates that there are two separate biological stocks of Redthroat Emperor in western and eastern Australian waters [Van Herwerden et al. 2009].

Here, assessment of stock status is presented at the biological stock level—Western Australia and East Coast Queensland.

Toggle content

Stock Status

Western Australia

A separate stock assessment of Western Australia Redthroat Emperor has not been conducted. Status of Western Australia Redthroat Emperor is inferred from assessments of a number of key indicator species considered to provide reliable indices of the fishing pressure on the entire suite of demersal species in this fishery. Indicator species were selected based on a range of factors, including inherent vulnerability, social/economic importance and management requirements [Newman et al. 2018]. Regular key indicator species assessments focus on West Australian Dhufish and Snapper, with aperiodic assessments of the other indicator species.

In 2007, an assessment of three indicator species (West Australian Dhufish, Snapper and Baldchin Groper) in the Western Australian management unit where Redthroat Emperor is exploited primarily identified that overfishing had been occurring, with fishing mortality rates (F) exceeding the limit reference point of 1.5 times the natural mortality rates (M) for those species [Wise et al. 2007]. The above evidence indicates that the biomass of the Western Australian biological stock of Redthroat Emperor is likely to be depleted and that recruitment is likely to be impaired.

Management arrangements for both the commercial and recreational sectors were introduced between 2007 and 2010 to recover stocks of all demersal species (including the Western Australian biological stock of Redthroat Emperor) in that management unit. These arrangements were designed to reduce effort to ensure annual retained catches of the demersal suite do not exceed 50 per cent of 2005–06 levels (i.e. < 450 tonnes [t] commercial and 250 t recreational). This recovery strategy is designed to reduce F to less than the threshold reference point (F=M) and increase spawning potential ratio (SPR) above the threshold (30 per cent of the pre-fishing level).

Commercial and recreational catches of the demersal suite of species have remained around or below 50 per cent of 2005–06 catches (the stock recovery benchmark) since management changes were introduced [Fairclough et al. 2018]. Following three years of commercial catches of one key indicator species (Snapper) being above its 50 per cent of 2005–06 catch level, further changes were introduced in 2015 to reduce effort and catches in the commercial fishery. This reduced commercial catches below the stock recovery benchmark [Fairclough et al. 2018]. Under the current management arrangements, commercial catches of Redthroat Emperor have remained below 50 per cent of 2005–06 levels (95 t) since 2009, i.e. 48–65 t. Annual recreational and charter catches are small (11 t) [Gaughan and Santoro, 2018, Ryan et al. 2017]. F and SPR for fully-recruited age classes of the key demersal indicator species in the most recent assessment (age frequency data for 2012–14) remained above and below their respective limit reference points. Additional analyses using a method which takes into account a change in fishing mortality following management intervention [Fisher 2013] identified a decrease in fishing mortality for cohorts recruited to the fishery since management changes commenced in 2008, compared with those that had recruited prior to these changes. This was identified for both indicator species, i.e. West Australian Dhufish F = 0.13 vs 0.21 and Snapper F = 0.14 vs 0.27 [cf. Fairclough et al. 2014; Department of Primary Industries and Regional Development, unpublished data]. This indicated that recent fishing mortality rates for the period 2008–17 were between limit and threshold reference points and thus, given recent lower catches, would have also decreased for the Western Australia biological stock of Redthroat Emperor, suggesting a recovering stock.

The above evidence indicates that the current level of fishing mortality should allow the stock to recover from its recruitment impaired state.

On the basis of the evidence provided above, the Western Australia biological stock is classified as a recovering stock.

Toggle content

Biology

Redthroat Emperor biology [VanHerwerden et al. 2009, Williams 2003, Williams et al. 2003]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Redthroat Emperor 20 years, 650 mm TL  Females: 1.2 years, 280 mm FL, 310 mm TL 
Toggle content

Distributions

Distribution of reported commercial catch of Redthroat Emperor
Toggle content

Tables

Fishing methods
Western Australia
Commercial
Hand Line, Hand Reel or Powered Reels
Hook and Line
Dropline
Gillnet
Unspecified
Fish Trap
Charter
Spearfishing
Hook and Line
Indigenous
Spearfishing
Hook and Line
Recreational
Spearfishing
Hook and Line
Management methods
Method Western Australia
Charter
Bag limits
Gear restrictions
Licence
Marine park closures
Passenger restrictions
Possession limit
Size limit
Spatial zoning
Temporal closures
Commercial
Effort limits
Gear restrictions
Limited entry
Size limit
Spatial closures
Spatial zoning
Total allowable effort
Vessel restrictions
Indigenous
Gear restrictions
Size limit
Spatial closures
Temporal closures
Recreational
Bag and possession limits
Bag limits
Gear restrictions
Licence (boat-based sector)
Marine park closures
Size limit
Spatial zoning
Temporal closures
Active vessels
Western Australia
44 in Charter, 12 in GDSMF, <3 in PTMF, <3 in WCDGDLIMF, 31 in WCDSIMF
Charter
Tour Operator (WA)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
PTMF
Pilbara Trap Managed Fishery (WA)
WCDGDLIMF
West Coast Demersal Gillnet and Demersal Longline (Interim) Managed Fishery (WA)
WCDSIMF
West Coast Demersal Scalefish (Interim) Managed Fishery (WA)
Catch
Western Australia
Commercial 53.10t in GDSMF, PTMF, WCDGDLIMF, WCDSIMF
Charter 5 t (2015−16)
Indigenous Unknown
Recreational 6 t (±1.1se) (2015−16)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
PTMF
Pilbara Trap Managed Fishery (WA)
WCDGDLIMF
West Coast Demersal Gillnet and Demersal Longline (Interim) Managed Fishery (WA)
WCDSIMF
West Coast Demersal Scalefish (Interim) Managed Fishery (WA)

Western Australia Data for Western Australia align with the 2017 calendar year.

Queensland Data for Queensland align with the 2016–17 financial year.

Queensland – Indigenous (management methods) Under the Fisheries Act 1994 (Qld), Indigenous fishers in Queensland are entitled 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.

Indigenous (management methods) 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.

Toggle content

Catch Chart

Commercial catch of Redthroat Emperor - note confidential catch not shown
Toggle content

References

  1. Fairclough, D, Walters, S and Holtz, M 2018, West coast demersal scalefish resource status report 2017, in DJ Gaughan and K Santoro (eds), 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.
  2. Fairclough, DV, Molony, BW, Crisafulli, BM, Keay, IS, Hesp, SA and Marriott, RJ, 2014, Status of demersal finfish stocks on the west coast of Australia, Fisheries Research Report No. 253, Department of Fisheries Western Australia, Perth.
  3. Fisher, E 2013, Tools for assessing data-limited fisheries and communicating stock status information, PhD thesis, Murdoch University, Perth.
  4. Gaughan, D and Santoro, K 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.
  5. Leigh, G, Williams, A, Begg, G, Gribble, N and Whybird, O 2006, Stock assessment of the Queensland east coast Red Throat Emperor (Lethrinus miniatus), Queensland Department of Primary Industries and Fisheries, Brisbane.
  6. Newman, SJ, Brown, JI, Fairclough, DV, Wise, BS, Bellchambers, LM, Molony, BW, Lenanton, RCJ, Jackson, G, Smith, KA, Gaughan, DJ, Fletcher, WJ, McAuley, RB, 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.
  7. Queensland Department of Agriculture and Fisheries 2018, Queensland Stock Status Assessment Workshop Proceedings 2018. Species Summaries. 19–20 June 2018, Brisbane.
  8. Ryan, KL, Hall, NG, Lai, EK, Smallwood, CB, Taylor, SM, Wise, BS 2017, Statewide survey of boat-based recreational fishing in Western Australia 2015/16. Fisheries research Report No. 287. Department of Primary Industries and Regional Development, Government of Western Australia, Perth.
  9. Van Herwerden, L, Aspden, WJ, Newman, SJ, Pegg, GG, Briskey, L and Sinclair, W 2009, A comparison of the population genetics of Lethrinus miniatus and Lutjanus sebae from the east and west coasts of Australia: evidence for panmixia and isolation, Fisheries Research, 100: 148–155.
  10. Webley, JAC, McInnes, K, Teixeira, D, Lawson, A and Quinn, R 2015. Statewide Recreational Fishing Survey 2013–14. Department of Agriculture and Fisheries, Queensland Government.
  11. Williams, AJ 2003, Spatial patterns in population biology of a large coral reef fish: what role can movement play? James Cook University, Townsville.
  12. Williams, AJ, Davies, CR, Mapstone, BD and Russ, GR 2003, Scales of spatial variation in demography of a large coral-reef fish: an exception to the typical model? Fishery Bulletin, 101: 673–683.
  13. Wise, BS, St John, J, Lenanton, RC (Eds.), 2007, Spatial scales of exploitation among populations of demersal scalefish: implications for management. Part 1: stock status of the key indicator species for the demersal scalefish fishery in the West Coast Bioregion. Final report to Fisheries Research and Development Corporation, Project 2003/052. Fisheries Research Report No. 163. Department of Fisheries Western Australia. 130 pp.

Downloadable reports

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