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There are five assessment units of Golden Snapper across Australia’s north. The WA, Regional NT, Gulf of Carpentaria and Eastern Australia assessment units are sustainable, whereas the Darwin Region management unit of the NT is classified as depleted.

Golden Snapper is a moderately long-lived (i.e. 30 years), late-maturing species that can reach a length of one metre [Cappo et al. 2013]. They are broadly distributed throughout the tropical and sub-tropical Indo-West Pacific with juveniles spending several years in estuarine and inshore reef habitats before migrating to nearshore reef environments (to a depth of at least 80 m) as they near sexual maturity [Allen 1985, Kiso and Mahyam, 2003, Tanaka et al. 2011].

The distribution of this species within Australian waters extends from the Kimberley region in Western Australia, around the north of the continent to the southern Great Barrier Reef (around Rockhampton) [Travers et al. 2009]. A study of the stock structure of Golden Snapper across this range suggests that many functionally separate adult populations are present at a scale of tens of kilometres, although boundaries are unknown [Saunders et al. 2016].

Golden Snapper experience moderate to high harvest rates in some Australian fisheries (particularly those targeting adults of this late-maturing species), which can cause localised depletion. However, it is extremely difficult to collect relevant biological and catch-and-effort information to assess each adult population unit.

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

Darwin Region

The Darwin Region represents the area within a radius of approximately 300 km of this population centre. Within this region, Golden Snapper is primarily caught by recreational fishers. Of the total Golden Snapper catch within the Darwin Region management unit, 70 per cent is taken by recreational anglers, 19 per cent by fishing tour operators, and 5 per cent by commercial fishers (predominantly in the Coastal Line Fishery). No estimates of the Indigenous harvest of Golden Snapper are available for this region. 

The most recent assessment [Saunders 2018] was an update of the 2014 Stock Reduction Analysis model [Grubert et al. 2013] including data up to and including 2017. The results indicate that the Greater Darwin Region remained overfished in 2017 (99 per cent probability) and existing fishing pressure will likely maintain the level of overfishing. The assessment estimated that biomass and egg production were 23 per cent of the unfished biomass (1970), indicating this stock is recruitment overfished. Given the recent information on the stock structure of this species [Saunders et al. 2016], it is likely that the assessment incorporates several populations. As the model is driven by the populations that receive the highest harvest rates in the Northern Territory the assigned status can be assumed to be representative of these heavily fished areas, with other less accessible areas being more lightly fished. The above evidence indicates that the stock is likely to be depleted and that recruitment is likely to be impaired.

In the Darwin Region, abundance, catch and catch rate have substantially declined over the past 10 years [NTG 2017]. The fisheries accessing these exploited stocks operate inshore and include the Coastal Line Fishery, the Barramundi Fishery, Fishing Tour Operators and recreational fishers. Catch limits and fishery area closures were implemented in 2015 to reduce harvest by an estimated 50 per cent to allow for the biomass of Golden Snapper stocks to recover [Grubert et al. 2013]. Given the species’ relatively slow growth rate, the management measures introduced in 2015 are unlikely to have yet supported measurable stock recovery. Furthermore, the results of the stock assessment indicate the stock continues to be overfished and the harvest rate is expected to prevent the stock from recovering from its recruitment impaired state. This level of fishing mortality is expected to prevent the stock from recovering from its recruitment impaired state.

On the basis of the evidence provided above, Golden Snapper in the Darwin Region (Northern Territory) management unit is classified as a depleted stock.

Gulf of Carpentaria

In the Gulf of Carpentaria management unit, Golden Snapper is mainly harvested by trawl vessels in the commercial Gulf of Carpentaria Developmental Fin Fish Trawl Fishery) (GOCDFFTF—Queensland) and Demersal Fishery (DF—Northern Territory). There is no reliable estimate of recreational harvest. Harvest from the adjacent Northern Territory jurisdiction has been low in recent years. Golden Snapper were also fished by foreign fleets between the 1950s and 1980s [O’Neill et al. 2011], and these catches (annual peak of 60 t) were higher than contemporary levels.

In the Queensland portion of this management unit commercial catches remained stable at 20–35 t annually from 2001–2011. Fish trawl effort from the GOCDFFTF declined markedly from 2012–14 as a result of trawl effort being transferred onto other management units. In 2019, there was no catch in the trawl sector and the catch by other fisheries was below 4 t. However, in the Northern Territory portion of this management unit an increase in the targeting of Saddletail Snapper by the DF in 2019 led to an increase of the catch (19 t) of Golden Snapper.

A preliminary assessment using catch data from all commercial fisheries applied to a modified catch-MSY model (developed by Martell and Froese [2013] and modified by Haddon [2018]), estimated that the 2019 biomass of Golden Snapper was 47 per cent of unfished levels [Saunders and Roelofs 2020b] suggesting that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. Similarly, the fishing mortality in 2019 was 0.12 which approximated the target level and was well below the limit reference point indicating that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

On the basis of the evidence provided above, the Gulf of Carpentaria management unit is classified as a sustainable stock.

Regional Northern Territory

Regional Northern Territory Region encompasses all waters outside of approximately 300 km from Darwin. Catch in this region is dominated by the finfish trawl vessels in the Demersal Fishery (DF). Additionally, foreign trawlers harvested substantial amounts (peak of 140 t) of Golden Snapper when they operated in this area in the 1970s and 1980s [Saunders 2020]. Catches by the domestic trawlers have been significantly lower and in 2019 was 22 t.  Given the fine-scale stock structure of this species [Saunders et al. 2016], 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. 

A preliminary assessment using catch data from all fishing sectors applied to a modified catch-MSY model (developed by Martell and Froese [2013] and modified by Haddon [2018]), estimated that the 2019 biomass of Golden Snapper was 76 per cent of unfished levels [Saunders 2020] suggesting that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. Similarly, the fishing mortality in 2019 was 0.06 which was well below the limit reference point  indicating that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

On the basis of the evidence provided above, Golden Snapper in the Regional Northern Territory management unit is classified as an sustainable stock.

Golden Snapper biology [Hay et al. 2005, Cappo et al. 2013,  Welch et al. 2014]

Distribution of reported commercial catch of Golden Snapper

Western Australia – Active Vessels Data is unreportable as there were fewer than three vessels operating in the PFTIMF, PTMF and WL.

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 – Recreational (Catch) Boat-based recreational catch is from 1 September 2017–31 August 2018. These data are derived from those reported in Ryan et al. 2019.

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 – 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 “…without derogating from any other law in force in the Territory, nothing in a provision of this Act or an instrument of a judicial or administrative character made under it limits the right of Aboriginals who have traditionally used the resources of an area of land or water in a traditional manner from continuing 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
 

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