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Mangrove Jack (2023)

Lutjanus argentimaculatus

  • Eliza Dedini (Department of Agriculture and Fisheries, Queensland)
  • Grant Johnson (Department of Industry, Tourism and Trade, Northern Territory)
  • Fabian Trinnie (Department of Primary Industries and Regional Development, Western Australia)
  • Stephen Newman (Department of Primary Industries and Regional Development, Western Australia)
  • Jeffrey Murphy (New South Wales Department of Primary Industries)

Date Published: June 2023

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Summary

The long-lived Mangrove Jack is classified as sustainable in WA, NT and the Gulf of Carpentaria, undefined in the East Coast QLD, and negligible in NSW.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Stock status Indicators
Western Australia Western Australia Sustainable

Catch, indicator species status

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Stock Structure

Mangrove Jack are a long lived (more than 50 years), late maturing species that can reach a length of over 1 m [Russell et al. 2003]. They are broadly distributed throughout the tropical and sub-tropical Indo-West Pacific [Allen 1985] and exhibit a biphasic life history pattern, where juveniles spend several years in freshwater and estuarine habitats before migrating offshore as they near sexual maturity and have been reported to a depth of at least 175 m [Pradella et al. 2013].

The distribution of this species within Australian waters extends from approximately Perth, Western Australia, around the north of the continent to Sydney, New South Wales [Pember et al. 2005; Russell et al. 2003]. Genetic analyses indicate that Mangrove Jack consist of a single biological stock across its Australian range [Russell et al. 2003]. This level of mixing is consistent with a life history that involves offshore spawning by adults. Juvenile fish have been shown to migrate from freshwater and estuarine habitats to offshore reef environments, sometimes moving up to 335 km [Russell et al. 2003]. Once these ontogenetic movements have occurred there have been no reports of adult fish undertaking extensive movements, although studies are limited. As such, limited evidence of adult movement in combination with evidence of varying stock status in different regions indicates that Mangrove Jack likely comprise separate management units.

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

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Stock Status

Western Australia

Most of the commercial catch of Mangrove Jack in WA is landed in the Pilbara Fish Trawl Managed Fishery. This species has also been landed in small quantities in the Gascoyne Demersal Scalefish Managed Fishery, Northern Demersal Scalefish Managed Fishery, Pilbara Line Fishery, and the Pilbara Trap Managed Fishery. Mangrove Jack are assessed on the basis of the status of several indicator species (including, for example, Red Emperor, Rankin Cod, and Bluespotted Emperor in the Pilbara region, and Red Emperor and Goldband Snapper in the Kimberley region) across the North Coast Demersal Resource (NCDR). These indicator species represent the entire inshore demersal suite of species occurring at depths of 30–250 m [Newman et al. 2018]. The indicator species in the Pilbara and Kimberley have been classified as sustainable based on the performance measures identified in the harvest strategy [Wakefield et al. 2023]. The level of risk associated with the sustainability of Mangrove Jack in the NCDR is assessed as low. This assessment of Mangrove Jack is also supported by the results of a data-limited Catch-MSY assessment, where recent catches are compared to model predictions for maximum sustainable yield (MSY).

Total catch of Mangrove Jack across WA over the last 10 years (2013–22) have ranged from 13.8–19.7 t, with a mean annual catch of 16.6 t. This is consistent with average catches across the previous 10 years being 17.9 t. For the last 10 years when reliable catch estimates for Mangrove Jack are available for both the recreational and charter sectors, these have been relatively low compared to commercial catches (i.e., comprising approximately 21% of the total catch). Results of analyses using a Catch-MSY model applied to data on annual catches for this species (1993–2022), showed that the annual catches since 2002 have fluctuated around the median model prediction for maximum sustainable yield (MSY), after having been above the 95% CI of MSY between 1997 and 2001. These results are also consistent with the predicted values for biomass in recent years being above BMSY, and fishing mortality remaining below FMSY. However, it is important to recognise that Catch-MSY is a data-limited technique with relatively strong assumptions, dependent on user inputs. For this assessment, these included specified ranges for initial depletion (0.4–0.8), based on likely catch levels from foreign fleets prior to the start of the time series, final depletion (0.15–0.7), based on recent catches relative to maximum recorded annual catch and the non-targeted nature of commercial fishing for this species, and low resilience (r=0.1–0.6, consistent with species longevity, of approximately 52 years in WA). Given the low level of overall landings of Mangrove Jack across multiple fisheries in Western Australia, recent catches of this species being less than the predicted MSY, and status of the indicator species for the NCDR, it is considered that the biomass of Mangrove jack in Western Australia is unlikely to be depleted and that current levels of fishing mortality is unlikely to be sufficiently high to cause the stock to become recruitment overfished. On the basis of the evidence provided above, Mangrove Jack in Western Australia is classified as a sustainable stock.

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Biology

Mangrove Jack biology [Russell et al. 2003; Pember et al. 2005; Piddocke et al. 2015]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Mangrove Jack

57 years, 1,019 mm FL

Male: approximately 7 years, 450 mm FL Female: approximately 8 years, 510 mm FL

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Distributions

Distribution of reported commercial catch of Mangrove Jack

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Tables

Fishing methods
Western Australia
Commercial
Hand Line, Hand Reel or Powered Reels
Otter Trawl
Fish Trap
Charter
Spearfishing
Hook and Line
Indigenous
Hook and Line
Unspecified
Recreational
Hook and Line
Management methods
Method Western Australia
Charter
Bag/possession limits
Limited entry
Passenger restrictions
Size limit
Spatial zoning
Commercial
Gear restrictions
Limited entry
Size limit
Spatial closures
Spatial zoning
Temporal closures
Vessel restrictions
Recreational
Bag/possession limits
Gear restrictions
Licence (Recreational Fishing from Boat License)
Size limit
Spatial closures
Catch
Western Australia
Commercial 12.71t
Charter 1.9 t, 2 t
Indigenous Unknown
Recreational 1.77 t ± 0.51 se, 2 t (2017–18)

Western Australia. Active Vessels data is unreportable as there were fewer than three vessels operating in Pilbara Fish Trawl Interim Managed Fishery and Pilbara Trap Managed Fishery.

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]. Shore based catches of Mangrove Jack are not known.

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.

Northern Territory – Recreational (Catch). Recreational Catch from West et al. [2022].

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.

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

Queensland – Recreational Fishing (Catch). Data are based at the whole of Queensland level and derived from statewide 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 has 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 available at: https://www.daf.qld.gov.au/business-priorities/fisheries/sustainable/harvest-strategy

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Catch Chart

Commercial catch of Mangrove Jack - note confidential catch not shown

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References

  1. Department of Agriculture and Fisheries 2023, Fishery Monitoring Program, Unpublished.
  2. FAO species catalogue, volume 6, snappers of the world. FAO Fisheries Synopsis 125.
  3. Haddon, M, Punt, A and Burch, P 2018, simpleSA: A package containing functions to facilitate relatively simple stock assessments. R package version 0.1.18.
  4. Martell, S and Froese, R 2013, A simple method for estimating MSY from catch and resilience. Fish and Fisheries 14:504–514.
  5. 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.
  6. 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, The State of Queensland, Department of Employment, Economic Development and Innovation, Brisbane, Queensland.
  7. Pember MB, Newman SJ, Hesp SA, Young GC, Skepper CL, Hall NG and Potter IC 2005, Biological parameters for managing the fisheries for Blue and King Threadfins, Estuary Rockcod, Malabar Grouper and Mangrove Jack in north-western Australia. Final Report to the Fisheries Research and Development Corporation (FRDC) on Project No. 2002/003. Centre for Fish and Fisheries Research, Murdoch University, Murdoch, Western Australia, Australia. 172p.
  8. Piddocke, TP, Butler, GL, Butcher, PA, Stewart, J, Bucher, DJ and Christidis, L 2015, Age and growth of mangrove red Snapper Lutjanus argentimaculatus at its cool-water-range limits, Journal of Fish Biology, 86, 1587–1600.
  9. Pradella, N, Fowler, AM, Booth, DJ and Macreadie, PI 2013, Fish assemblages associated with oil industry structures on the continental shelf of north-western Australia. Journal of Fish Biology, 84(1): 247–255.
  10. Russell, DJ, McDougall, AJ, Fletcher, AS, Ovenden, JR and Street, R 2003, Biology, management and genetic stocks structure of mangrove jack (Lutjanus argentimaculatus) in Australia. FRDC Project Number 1999/122, Department of Primary Industries, Queensland and the Fisheries Research Development Corporation, Brisbane.
  11. Ryan KL, Lai, EKM and 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.
  12. Saunders, T 2020, Northern Territory Mangrove Jack Stock Status Summary—2020. Unpublished Fishery Report
  13. Saunders, T and Roelofs, A 2020, Gulf of Carpentaria Mangrove Jack Stock Status Summary—2020. Unpublished Fishery Report
  14. Teixeira, D, Janes, R and Webley, J 2021, 2019/20 Statewide Recreational Fishing Survey Key Results. Project Report. State of Queensland, Brisbane. In press.
  15. Wakefield, C, Trinnie, F, Skepper, C, Boddington, Newman, SJ, and Steele, A 2023, North Coast Demersal Resource Status Report 2022. pp. 167–176. In: Gaughan, D.J. 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.
  16. West, LD, Stark, KE, Dysart, K and Lyle, JM 2022, Survey of recreational fishing in the Northern Territory: 2018 to 2019, Northern Territory Fisheries, Darwin.

Downloadable reports

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