*

Silver Trevally inhabits estuarine and coastal waters throughout southern temperate Australia. Of the seven separate Australian stocks, five (in WA, SA, VIC, TAS and the Commonwealth) are sustainable. The NSW stock is depleted and the QLD stock is undefined.  

Silver Trevallies comprises a complex of species that inhabits estuarine and coastal waters (depths of 10–230 m) throughout southern temperate Australia, from southern Queensland, south through New South Wales, Tasmania, Victoria, South Australia and southern and central Western Australia [Smith-Vaniz and Jelks 2006, Bearham et al. 2020].

The biological stock structure of Silver Trevallies is uncertain. Fisheries are based on a species complex that varies by region, with Pseudocaranx georgianus present in all jurisdictions except Queensland, Pseudocaranx wrighti present in all jurisdictions except Queensland and New South Wales, Pseudocaranx dinjerra only present in Western Australia, and Pseudocaranx sp. ‘dentex’ only present in Queensland [Smith-Vaniz and Jelks 2006, Gomon et al. 2008, Bearham et al. 2020]. Investigations of population connectivity and post-settlement movement are also limited. Despite fast swimming ability, tag-recapture studies in Western Australia, New South Wales and New Zealand indicate restricted post-settlement movement of P. georgianus, potentially leading to ecological stock structuring over moderate (hundreds of kilometres) spatial scales [James 1980, Fairclough et al. 2011, Fowler et al. 2018].

Here, assessment of stock status is presented at the jurisdictional level—Commonwealth, Western Australia, Queensland, New South Wales, Victoria, Tasmania and South Australia.

Tasmania

In Tasmanian waters, Silver Trevallies (only P. georgianus recorded) are byproduct species of the Tasmanian Scalefish Fishery, caught predominately using gillnet and beach seine gears. Recorded commercial catches have been low, with a maximum of 8 t recorded in 1998 and an annual average of approximately 4 t recorded over the past ten years. The total recorded commercial catch in 2018–19 was 3.7 t. Commercial catch and effort appear to show a positive relationship, but given that the species are not actively targeted, catch rates are not considered to provide a reliable index of relative abundance. 

Four estimates of recreational catches using line and gillnet methods since 2000–01 were generally higher than those of the commercial sector, varying between a low of 1.9 t in 2012–13 and a peak of 8.5 t in 2017–18 [Lyle et al. 2019]. In comparison to other jurisdictions, total catch and effort in Tasmania appear to be low, indicating that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired. The data further indicate that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

On the basis of this evidence, Silver Trevallies in Tasmania are classified as a sustainable stock.

Silver Trevallies biology [Rowling and Raines 2000]

Distribution of reported commercial catch of Silver Trevallies. No catch distribution data are provided for Queensland as Silver Trevallies are not distinguished from other trevally species in relevant Queensland commercial fishery logbooks.

Commonwealth – Commercial (Management Methods/Catch) Data provided for the Commonwealth align with the Commonwealth Southern and Eastern Scalefish and Shark Fishery for the 2018-19 financial year.

Commonwealth – Recreational The Commonwealth does not manage recreational fishing in Commonwealth waters. Recreational fishing in Commonwealth waters is managed by the state or territory immediately adjacent to those waters, under its management regulations.  

Commonwealth – Indigenous The Australian government does not manage non-commercial Indigenous fishing in Commonwealth waters, with the exception of Torres Strait. In general, non-commercial Indigenous fishing in Commonwealth waters is managed by the state or territory immediately adjacent to those waters.

Western Australia – Recreational (management methods) In Western Australia, a licence is required to recreationally fish from a powered vessel.

Western Australia – Recreational (Catch) Shore based catches are unknown, thus landings would be underestimated.

Queensland – Indigenous (management methods) for more information see https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing

New South Wales – Recreational (Catch) Murphy et al. [2020].

New South Wales – Indigenous https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing

Victoria – Commercial (catch) Silver trevally (Pseudocaranx georgianus) is not differentiated from other trevallies caught in Victorian commercial fisheries.

Victoria – Indigenous A person who identifies as Aboriginal or Torres Strait Islander is exempt from the need to obtain a Victorian recreational fishing licence, provided they comply with all other rules that apply to recreational fishers, including rules on equipment, catch limits, size limits and restricted areas. Traditional (non-commercial) fishing activities that are carried out by members of a traditional owner group entity under an agreement pursuant to Victoria’s Traditional Owner Settlement Act 2010 are also exempt from the need to hold a recreational fishing licence, subject to any conditions outlined in the agreement. Native title holders are also exempt from the need to obtain a recreational fishing licence under the provisions of the Commonwealth’s Native Title Act 1993.

Tasmania – Indigenous (management methods) In Tasmania, Indigenous persons engaged in traditional fishing activities in marine waters are exempt from holding recreational fishing licences, but must comply with all other fisheries rules as if they were licensed. If using pots, rings, set lines or gillnets, Indigenous fishers must obtain a unique identifying code (UIC). The policy document "Recognition of Aboriginal Fishing Activities” details application procedures for issuing a UIC.

Commercial catch of Silver Trevallies - note confidential catch not shown

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