Black Jewfish Protonibea diacanthus

Northern Territory

The most recent assessment (2011) estimates that the biomass of Black Jewfish in the Northern Territory is at approximately 62 per cent of unfished biomass ¹. Egg production is estimated at 38 per cent of unfished levels, resulting in a high probability (71 per cent) that Black Jewfish stocks have been overfished and a moderate probability (21 per cent) that current fishing pressure is continuing to cause overfishing¹. The assessments are driven by the populations that receive the highest harvest rates, so the status for the Northern Territory can be assumed to reflect the highest level of exploitation that occurs on any population. The immediate area of concern is in waters around Darwin, where most of the fishing pressure occurs and where abundance, catch and catch rate have substantially declined since 2004². Black Jewfish have also been shown to be highly susceptible to barotrauma when caught in waters deeper than 10 metres³. It is estimated that fishing pressure needs to be reduced by a further 20 per cent to allow the biomass of Black Jewfish stocks to recover¹. The evidence provided above indicates that these stocks are recruitment overfished and that the current levels of fishing pressure are expected to prevent the stocks from recovering from their recruitment overfished state.

On the basis of the evidence provided above, Black Jewfish in the Northern Territory is classified as an overfished stock.

Gulf of Carpentaria (Queensland) management unit

In the Gulf of Carpentaria (Queensland) management unit, Black Jewfish are taken by commercial net fishers and recreational anglers. Commercial catches of Black Jewfish in the Queensland Gulf of Carpentaria Inshore Fin Fish Fishery have decreased from a reported historical high of 33 tonnes (t) in 1990 to less than 0.5 t in 2013⁴. However, specific reporting of Black Jewfish commercial harvest ceased in 2006, and catches reported as ‘Jewfish—Other’ have averaged 6 t per year since this change; Black Jewfish are likely the major component of this harvest. From 1999 to 2000, there was a distinct lack of large mature fish found in the north Cape York region⁵. The overall downward trend in catches and the reduced spawning biomass, combined with the vulnerable biology of Black Jewfish (late maturing, aggregating to spawn), resulted in a 2-year ban on fishing for Black Jewfish in key aggregation areas. In 2002, Queensland prohibited the harvest of Black Jewfish in the north Cape York region (north of Crab Island)⁴. No studies have been undertaken to measure recovery in this region or the overall biomass of Black Jewfish in the Queensland part of the Gulf of Carpentaria.

There are no reliable estimates of recreational harvest for Black Jewfish in the Queensland Gulf of Carpentaria⁴, but it is known as a popular recreational species in the region. The Queensland legal size limit (60 cm total length) in the Gulf of Carpentaria is well below the reported age of first maturity for females (85–90 cm total length) and may not be effective in protecting spawning females from fishing. A conservative possession limit (two fish) reduces recreational fishing pressure on the stock. Overall, insufficient information is available to confidently classify the status of the stock.

On the basis of the evidence provided above, the management unit is classified as an undefined stock.

Queensland east coast management unit

Black Jewfish are taken by commercial net fishers and recreational anglers on the Queensland east coast. The East Coast Inshore Fin Fish Fishery (Queensland) contributes minimal quantities (5-year average = 2 t per year) to the overall Queensland east coast harvest. There are no reliable estimates of recreational harvest⁶. The legal size limit (75 cm total length) is below the reported age of first maturity for females and may not be effective in protecting spawning females from fishing. A conservative possession limit (two fish) reduces recreational fishing pressure on the stock. Insufficient information is available to confidently classify the status of the stock.

On the basis of the evidence provided above, the management unit is classified as an undefined stock.

Western Australia

Black Jewfish are not a target species in the Kimberley Gillnet and Barramundi Managed Fishery of Western Australia but are landed in small quantities as byproduct⁷. They have also been landed in very small quantities as byproduct in the Nickol Bay Prawn Managed Fishery, the Pilbara Fish Trawl Interim Managed Fishery and the Pilbara Line Fishery. Black Jewfish catches have only been reported from a small area of their range in Western Australia. They are landed in small quantities by charter fishers, primarily in the Kimberley region of Western Australia. Given the low level of take of Black Jewfish in Western Australia, it is unlikely that this species is recruitment overfished, or that the level of fishing mortality is likely to cause it to become recruitment overfished. However, insufficient information is available to confidently classify the status of Black Jewfish in Western Australia.

On the basis of the evidence provided above, Black Jewfish in Western Australia is classified as an undefined stock.