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Stock Status Overview
|Northern Territory||Northern Territory||DF,CLF,TRF||Undefined||Catch, trigger reference points|
- Demersal Fishery, Coastal Line Fishery, Timor Reef Fishery (NT)
Red Emperor is exploited primarily in the North Coast Bioregion of Western Australia1. Smaller catches are taken in the Northern Territory and Queensland. Red Emperor is one of the indicator species used to assess the status of the demersal resources in the North Coast Bioregion. In Western Australia, analysis of otolith stable isotopes indicates that Red Emperor comprises a number of separate biological stocks, one in each of the main management regions, the Kimberley, the Pilbara and the Gascoyne2,3. Reporting of status is undertaken at the level of these individual biological stocks in Western Australia. Because multiple stocks are present within Western Australia, there is a high likelihood of multiple stocks across the Northern Territory and Queensland. However, stock delineation is not currently known in these jurisdictions. In the Northern Territory, status is reported at the jurisdictional level, while in Queensland, status is reported at the level of management units.
Here, assessment of stock status is presented at the biological stock level—Gascoyne, Pilbara and Kimberley (Western Australia); the jurisdictional level—Northern Territory; and the management unit level—Gulf of Carpentaria and East coast (Queensland).
Red Emperor comprises around two per cent of the total catch in the Northern Territory offshore snapper fisheries and is managed as part of the ‘group’ species in the Timor Reef and Demersal Fisheries (Northern Territory). The performance indicators and trigger points are based on significant changes in species composition of the catch, used to indicate whether significant catch increases warrant further management efforts. Since 1995, catches of Red Emperor have varied between 1.5 and 4.5 per cent of the total annual catch and catches have increased from 20 t in 1995 to 64 t in 2015. The trigger point of an increase of more than 15 per cent of the species’ previous year’s catch weight, or of a species becoming dominant relative to other species in the group, was not reached in 2015.
This evidence suggests that the current level of fishing mortality is unlikely to cause Red Emperor in the Northern Territory to become recruitment overfished. However, there is insufficient information available to confidently classify the status of this stock.
Based on the evidence provided above, Red Emperor in the Northern Territory is classified as an undefined stock.
Red Emperor biology5,8–10
|Species||Longevity / Maximum Size||Maturity (50 per cent)|
|Red Emperor||40–45 years; 800 mm FL (860 mm TL)||4–6 years; 430–460 mm FL (460–490 mm TL)|
Distribution of reported commercial catch of Red Emperor
|Hand Line, Hand Reel or Powered Reels|
|Total allowable catch|
|8 in CLF, 8 in DF, 8 in TRF|
- Coastal Line Fishery (NT)
- Demersal Fishery (NT)
- Timor Reef Fishery (NT)
|Commercial||64.76t in DF,CLF,TRF|
|Recreational||0.6 t, Unknown|
- Demersal Fishery, Coastal Line Fishery, Timor Reef Fishery (NT)
a Queensland – Commercial (fishing methods) In Queensland, Golden Snapper is trawled in only one of the Queensland fisheries in which it is caught commercially - the Gulf of Carpentaria Developmental Fin Fish Trawl Fishery
b Queensland – Indigenous (fishing methods) In Queensland, data for the Coral Reef Fin Fish Fishery and Deep Water Fin Fish Fishery relates to the 2014–15 financial year. Data for the Gulf of Carpentaria Line Fishery and Gulf of Carpentaria Developmental Fin Fish Trawl Fishery are for the 2015 calendar year.
c Queensland – Indigenous (management methods) In Queensland, under the Fisheries Act 1994 (Qld), indigenous fishers 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. d Western Australia- Recreational (catch) Boat-based recreational catch from 1 May 2013–30 April 2014.
Commercial catch of Red Emperor
Effects of fishing on the marine environment
- The maintenance of high levels of biomass of Red Emperor in each of the fisheries in Western Australia results in a negligible eco-trophic risk from these fisheries. Furthermore, there has been no reduction in either mean trophic level or mean maximum length in the finfish catches recorded within the Pilbara or Kimberley in Western Australia (that is, no indication of fishing down of the food web)11.
- Available information indicates that there are minimal impacts on habitat from trap or line based fishing methods for Red Emperor4.
- Impacts to the habitat from trawling are expected to be minimal as trawling is restricted to only seven per cent of the north-west shelf and parts of the Northern Territory. Trawling does not occur in the Kimberley region1,4,8. Trawl nets in the Northern Territory have been designed to fish off the sea bed, reducing interaction with benthic habitats12.
- The bycatch of dolphins and turtles has been reduced significantly since the introduction of exclusion grids in Pilbara fish trawl nets in 2005. Given the area of distribution and expected population size of these protected species, the impact of the fish trawl fishery on the stocks of these protected species is likely to be minimal15,16. Gear and fishing modification continue to reduce this level of interaction1,4,15.
- The main Western Australian fisheries that target Red Emperor have received either full Export Exemption or Approved Wildlife Trade Operation Exemption accreditation under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The Northern Territory fisheries that target Red Emperor have received full Export Exemption accreditation under the Australian EPBC Act. The Queensland fisheries that target Red Emperor have received an Approved Wildlife Trade Operation Exemption accreditation under the EPBC Act. These assessments, subject to adherence to accompanying conditions and recommendations, demonstrate that these fisheries are managed in a manner that does not lead to overfishing, and that fishing operations have a minimal impact on the structure, productivity, function and biological diversity of the ecosystem.
Environmental effects on Red Emperor
- Climate change and climate variability has the potential to impact fish stocks in a range of ways including influencing their geographic distribution (for example, latitudinal shifts in distribution). However, it is unclear how climate change may affect risks to sustainability for this species.
- Changes in oceanographic conditions have the potential to impact on the replenishment rates of fish populations and also to impact on individual growth rates and spawning output13.
- 1 Fletcher, WJ and Santoro, K (eds.) 2015, 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.
- 2 Stephenson, PC, Edmonds, JS, Moran, MJ and Caputi, N 2001, Analysis of stable isotopes to investigate stock structure of red emperor and Rankin cod in northern Western Australia, Journal of Fish Biology, 58: 126–144.
- 3 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 (2): 148–155.
- 4 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, WJ and Santoro, K (eds.) 2015, 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.
- 5 O’Neill, MF, Leigh, GM, Martin, JM, Newman, SJ, Chambers, M, Dichmont, CM and Buckworth, RC 2011, Sustaining productivity of tropical red snappers using new monitoring and reference points, Final Report to the Fisheries Research and Development Corporation, Project 2009/037. 104p.
- 6 Leigh, GM and O'Neill, MF 2016, Gulf of Carpentaria Finfish Trawl Fishery: Maximum Sustainable Yield, Agi–Science Queensland, Department of Agriculture and Fisheries, Queensland.
- 7 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.
- 8 Newman, SJ and Dunk, IJ 2002, Growth, age validation, mortality, and other population characteristics of the red emperor snapper, Lutjanus sebae (Cuvier, 1828), off the Kimberley coast of North–Western Australia, Estuarine, Coastal and Shelf Science,55 (1): 67–80.
- 9 Newman, SJ, Skepper, CL and Wakefield, CB 2010, Age estimation and otolith characteristics of an unusually old, red emperor snapper (Lutjanus sebae) captured off the Kimberley coast of north–western Australia, Journal of Applied Ichthyology, 26 (1): 120–122.
- 10 Newman, SJ, Moran, MJ and Lenanton, RCJ 2001, Stock assessment of the outer–shelf species in the Kimberley region of tropical Western Australia, final report to the Fisheries Research and Development Corporation, project 97/136.
- 11 Hall, NG and Wise, BS 2011, Development of an ecosystem approach to the monitoring and management of Western Australian fisheries, Fisheries Research and Development Corporation Report, Project 2005–063, Fisheries Research Report 215, Western Australian Department of Fisheries, Perth.
- 12 Northern Territory Government 2015, Status of Key Northern Territory Fish Stocks Report 2013. Northern Territory Government, Department of Primary Industry and Fisheries, Fishery Report No. 114.
- 13 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 (1): 106–124.
- 14 Wakefield, CS, Santana-Garcon, J, Dorman, SR, Blight, S, Denham, A, Wakeford, J, Molony, BW and
- 15 Newman, SJ 2016, Performance of bycatch reduction devices varies for chondrichthyan, reptile, and cetacean mitigation in demersal fish trawls: assimilating subsurface interactions and unaccounted mortality, ICES Journal of Marine Science in press
- 16 Molony, BW, Wakefield, CB, Newman, SJ, O’Donoghue, S, Joll, L and Syers, C 2015, The need for a broad perspective concerning fisheries interactions and bycatch of marine mammals, pp.65-78, In: Kruse, GH, An, HC, DiCosimo, J, Eischens, CA, Gislason, GS, McBride, DN, Rose, CS and Siddon, CE (eds.). Fisheries Bycatch: Global Issues and Creative Solutions. Alaska Sea Grant, University of Alaska Fairbanks.