*

Spanish Mackerel are widely distributed across several fisheries in WA, NT, Qld, NSW and the Torres Strait. Three of the five stocks are sustainable, the Gulf of Carpentaria stock is depleting, and the East Coast stock is depleted.

Genetic evidence indicates that there are three biological stocks of Spanish Mackerel across northern Australia [Moore et al. 2003]; however, evidence from otolith microchemistry, parasite analysis and limited adult movement (at scales greater than 100 km) indicates that there are likely to be a number of smaller biological stocks with limited interaction [Buckworth et al. 2007, Lester et al. 2001, Moore et al. 2003]. Each jurisdiction is likely to have multiple biological stocks within its boundaries; however, the difficulty in obtaining relevant biological, and catch and effort, information to assess each stock individually has meant that not all assessments are undertaken at the biological stock level. Those that are, are based on the populations that receive the highest harvest rates; their status can be assumed to be representative of the highest level of exploitation that occurs on any population within each management unit or jurisdiction.

Here, assessment of stock status is presented at the biological stock level—Torres Strait Spanish Mackerel Fishery and East Coast (Queensland and New South Wales); management unit level—Mackerel Managed Fishery (Western Australia), Gulf of Carpentaria (Queensland); and jurisdictional level—Northern Territory.

Northern Territory

The harvest of Spanish Mackerel in the Northern Territory is managed through a catch-sharing arrangement between all user groups [NTG 2009]. This agreement aims to maintain the cumulative harvest of Spanish Mackerel within a precautionary allowable catch of 450 tonnes (t) per annum. The proportion of the allowable catch allocated to each user group was based on historical logbook data and catch estimates from the National Recreational and Indigenous Fishing Survey [Henry and Lyle 2003] as follows: 76% (342 t) to Spanish Mackerel Fishery licensees, 3% (13.5 t) to Offshore Net and Line Fishery licensees, 1% (4.5 t) to Demersal Fishery licensees, 3% (13.5 t) to Fishing Tour Operator licensees, 16% (72 t) to recreational fishers and 1% (4.5 t) to Indigenous fishers.

The cumulative catch by all sectors averaged ~370 t for the five years spanning 2010–2014, with the proportion of the catch caught by each sector similar to the allocations described above (i.e. 71%, 6%, <1%, 5%, 16% and 2%, respectively). However, the average cumulative catch over the last five years (2015-2019) has risen to over 500 t, primarily due to an increase in catch by Spanish Mackerel Fishery licensees, who harvested 79% of the resource during this period.

The most recent assessment of the Spanish Mackerel resource in the Northern Territory (using data to 2019) indicated that stocks are unlikely to have dropped below 68% of the unfished biomass and that the biomass at the conclusion of 2019 was 72% of the unfished (1973) level [Grubert et al., unpublished]. This being the case, the biomass of the Northern Territory stock of Spanish Mackerel is not considered to be recruitment impaired. 

The same assessment indicated that the current (2019), relative fishing mortality rate (i.e. U₂₀₁₉/U_MSY) for the Northern Territory stock of Spanish Mackerel was 0.43, less than half of the rate required to achieve MSY (i.e. there is scope to increase the harvest of this species, noting that there is spatial concentration of fishing effort that needs to be monitored and managed). The current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

On the basis of the evidence provided above, Spanish Mackerel in the Northern Territory is classified as a sustainable stock.

Spanish Mackerel biology [McPherson 1992, McPherson 1993, QDAFF 2013]

Commonwealth – Commercial (active vessels) Total number of TIB licences; this is not an indicator of licence activity.

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

Commonwealth – Indigenous (a) The Australian Government does not manage non-commercial Indigenous fishing in Commonwealth waters, with the exception of the Torres Strait. In general, non-commercial Indigenous fishing in Commonwealth waters is managed by the state or territory immediately adjacent to those waters. In the Torres Strait, both commercial and non-commercial Indigenous fishing is managed by the Torres Strait Protected Zone Joint Authority (PZJA) through the Australian Fisheries Management Authority (Commonwealth); the Department of Agriculture, Fisheries and Forestry (Queensland); and the Torres Strait Regional Authority. The PZJA also manages non-Indigenous commercial fishing in the Torres Strait; and (b) Subject to the defence that applies under 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 – Recreational (catch) Western Australian boat-based recreational catch surveys from 1 Sept 2017–30 Aug 2018 [Ryan et al 2019]. Shore-based recreational catches are largely unknown.

Western Australia – Recreational (Management Methods) Western Australian boat-based recreational licence required.

Western Australia – Charter (catch) is an estimate based on numbers of fish caught multiplied by their average weight.

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

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

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

Commercial catch of Spanish Mackerel - note confidential catch not shown. Years shown on this graph are Australian financial years (e.g. 2015 refers to the financial year beginning 01 July 2014 and ending 30 June 2015).

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