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Black Jewfish is assessed as sustainable in WA, Regional NT, the Darwin Region and on the QLD East Coast. Stocks in the Gulf of Carpentaria are undefined, with limited information available.

Black Jewfish is a widespread Indo-Pacific species found from Exmouth Gulf in Western Australia, across Northern Australia to the central East Coast of Queensland. The stock structure for this species has been investigated across its entire Australian range. Recent research shows contrasting results in terms of the spatial extent of stocks based on different marker types. In the Northern Territory and Western Australia genetic markers suggested stock connectivity at spatial scales of 100s of kms, while parasites and otolith chemistry have indicated that stocks may exist at scales as low as 10s of kms [Porter et al. 2023; Randall et al. 2023; Saunders et al. 2016a; Taillebois et al. 2017], In Queensland waters, recent tagging and population genetic analysis suggested stock connectivity over 100s of kms, fish moving up to 250km, and genetic stock structure of up to approximately 700km [Williams et al. 2023]. Genetic stock structure research also showed a shared biological stock is present across Queensland and Northern Territory waters within the Gulf of Carpentaria.

Here assessment of stock status is presented at the jurisdictional level—Western Australia, and at the management unit level—Darwin Region and Regional Northern Territory (Northern Territory); Gulf of Carpentaria (Northern Territory and Queensland) and Queensland East Coast.

Darwin Region

This management unit is where the highest catches of Black Jewfish occur in the Northern Territory and is within an approximate radius of 300 km of Darwin. Black Jewfish is a targeted species of the Coastal Line Fishery, contributing 68% of the total harvest; the recreational fishing sector, contributing 21%; Fishing Tour Operators, contributing 5% and the rest comprising other commercial fisheries and an unknown Indigenous harvest.  Given the fine-scale stock structure of this species in this region [Porter et. al 2023; Randall et al. 2023; Saunders et al. 2016a; Taillebois et al. 2017], it is likely that this management unit incorporates several populations. Consequently, the assessment has been driven by the populations that receive the highest harvest rates in this management unit and the assigned status can be assumed to be representative of these heavily-fished areas, with other less accessible areas being more lightly-fished. It is worth noting commercial catch quotas now apply for management areas within the Darwin Region (Channel Point, Mitchell Point and Point Stuart) to further safeguard these spatially separated populations. 

A 2014 stock assessment using a Stock Reduction Analysis indicated that Black Jewfish were overfished, and that overfishing was occurring [Saunders et al. 2016b]. However, the most recent assessment using data up to 2019, indicates that current biomass has increased significantly to 93% of unfished levels [Saunders 2020a] suggesting that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. While this biomass estimate is probably overly optimistic, there is evidence that strongly supports a significant increase in the abundance of Black Jewfish and the recovery of the stocks within this management unit. This includes successive years of above-average recruitment (indicated by the reduction in average length of monitored catches and an increase in the number of fish caught), a previous stock assessment indicating that the biomass had recovered to 50% of unfished levels [Penny et al. 2018] as well as the management measures (catch limits and area closures) introduced in 2015 that have reduced catches from the peaks that occurred in the mid-2000s [NTG 2017]. The model outputs also indicate the current fishing mortality is only 24% of that required to attain Maximum Sustainable Yield indicating that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired. However, it should be noted that the observable age structure of this population, when compared to recent evaluation of the east coast stock, provides some evidence that the Darwin population may be age truncated [Randall et al. 2023; Williams et al. 2023].

On the basis of the evidence provided above, Black Jewfish in the Darwin Region management unit is classified as a sustainable stock.

Gulf of Carpentaria

In the Gulf of Carpentaria, Black Jewfish is taken by commercial trawl, net and line fishers as well as by recreational anglers and traditional indigenous fishers. Recent research highlighted that the gulf fishery encompasses a single shared genetic stock which extends as far as the top of Cape York Peninsula [Williams et al. 2023]. Black Jewfish was exposed to historical fishing from foreign fleets during the 1950s to the 1980s [O’Neill et al. 2011], however, these historical catches were relatively low (< 10 t).

In the Queensland portion of this management unit concerns over an increase in Black Jewfish targeting and catches due to the high value placed on Black Jewfish swim bladders led to the introduction of a 6 t TACC on 1 January 2020. The TACC is applied to the commercial sector but the fishery is yet to reach this limit. A limiting factor in the Queensland Gulf Commercial fishery not being able to catch the TACC is due to the current regulatory conditions (i.e. not allowing Black Jewfish to be line caught), rather than any lack of availability of fish. Prior to the TACC commercial harvest had averaged 8 t over the 2015–19 calendar year period and peaking at 13.5 t in 2016 in the Gulf of Carpentaria Inshore Fin Fish Fishery.

Black Jewfish are particularly vulnerable to fishing pressure due to their tendency to aggregate [Phelan 2008]. There is evidence that targeted fishing of Black Jewfish aggregations by traditional indigenous fishers in this management unit through the mid-late 1990s, while producing relatively low catches in absolute terms, was sufficient to significantly reduce abundance of large mature fish in the northern Cape York region [Phelan 2002]. The perceived overfishing of this aggregation area resulted in a two-year ban on fishing for Black Jewfish which was further extended as a permanent closure [Roelofs 2003]. No studies have been undertaken to measure recovery of this aggregation area, however, Williams et al. [2023] indicates that fishing does still occur but not at historical levels. The Northern Territory Demersal Fishery trawl fishery began increasing effort in 2012, resulting in higher levels of harvest of Black Jewfish in the western Gulf of Carpentaria. These catches are likely to be from the same stock as the Cape York aggregation so the impacts of this fishing activity may be connected. Additionally, while Black Jewfish are a popular recreational species in the Gulf of Carpentaria, there are no reliable estimates of recreational harvest [Roelofs 2003; Webley et al. 2015]. There is insufficient evidence to confidently classify the status of this management unit.

On the basis of the evidence provided above, Black Jewfish in the Gulf of Carpentaria management unit is classified as an undefined stock.

Regional Northern Territory

This management unit represents all Northern Territory waters outside the Darwin Region and Gulf of Carpentaria management units. Catch of Black Jewfish in this region is dominated by the finfish trawl vessels in the Demersal Fishery (DF). Additionally, foreign trawlers harvested substantial amounts (peak of 70 t) of Black Jewfish when they operated in this area in the 1970s and 1980s [Saunders 2020b]. Catches by the domestic trawlers have been significantly lower and for the period 2013 to 2022 averaged 6 t. Given the fine-scale stock structure of this species in the Darwin Region [Porter et al. 2023; Randall et al. 2023; Saunders et al. 2016a; Taillebois et al. 2017], it is likely that this management unit incorporates several populations. Consequently, the assessments will be driven by the populations that receive the highest harvest rates in this management unit and the assigned status can be assumed to be representative of these heavily-fished areas, with other less accessible areas being more lightly-fished.  

An assessment was undertaken using catch data from all commercial fisheries to 2019 applied to a modified catch-MSY model (developed by Martell and Froese [2013] and modified by Haddon et al. [2018]). The results from the assessment indicate that the inferred biomass exceeded the target reference point, with the 95% confidence intervals positioned above the target [Saunders 2020a]. This indicates that the stock was unlikely to be depleted and that recruitment is unlikely to be impaired. Similarly, the fishing mortality in 2019 (7.5 t) was 0.04 which was well below the limit reference point indicating that the current level of fishing mortality was unlikely to cause the stock to become recruitment impaired. The average catch over the last 10 years has remained low (12 t) and although catch increased from 2019 (14 t in 2022) this harvest level remains well below the limit reference point. 

On the basis of the evidence provided above, Black Jewfish in the Regional Northern Territory management unit is classified as a sustainable stock.

Black Jewfish biology [Phelan 2002; Welch et al. 2014; Williams et al. 2023]

Distribution of reported commercial catch of Black Jewfish. The Commercial Catch distribution of black jewfish in Queensland is limited by data confidentiality and management arrangements. As a result the map is not representative of the species distribution or catch distribution in Queensland

Western Australia – Recreational (Catch). Boat-based recreational catch if 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 Licence 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 – Active Vessels. Data is confidential as there were fewer than three vessels operating in the Pilbara Fish Trawl Interim Managed Fishery.

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.

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

Queensland – Recreational Fishing (Catch). Data with high uncertainty (Residual Error > 50 %) have been excluded and listed as unknown. More information available at: https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/monitoring-reporting/statewide-recreational-fishing-surveys

Queensland – Commercial (Catch). Queensland commercial 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

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