School mackerel monitoring

Biology

School mackerel is a schooling species that lives in shallow waters along the Queensland coast.

School mackerel may be mistaken for other mackerel species. They are closely related to Spanish and spotted mackerel but show differences in their habitat preference, feeding and behaviour.

Spanish and spotted mackerel live in offshore waters and undertake large annual migrations, while school mackerel prefer coastal waters including embayments.

School mackerel feed on a range of animals, while Spanish and spotted mackerel target schools of bait fish.

School mackerel mature around two years of age and may live up to 10 years. On the east coast there are thought to be two stocks - a northern and southern stock separated by a mixing zone located between Townsville and Proserpine (19.5°S to 20.5°S) (Figure 2).

Figure 2: Map of Queensland, Australia showing locations of northern and southern school mackerel stocks and mixing zone

The fishery

In Queensland, school mackerel is an important commercial species. Together with Spanish, spotted and grey mackerel, they provide fresh fish to seafood markets.

School mackerel are landed as part of the East Coast Inshore Fin Fish Fishery and Pelagic Line Fishery. Between 68 tonnes and 103 tonnes were harvested annually from 2014 to 2018 (Figure 3). Fish are mostly harvested using gill nets, with more than 90% of the total harvest coming from the southern stock.

School mackerel is also a popular target species for recreational fishers. The most recent statewide recreational fishing survey (2013–14) estimated harvest at 43 tonnes for the east coast, with more than half coming from the northern stock.

Figure 3: Commercial school mackerel harvest from southern stock, 2014–18 (blue bars represent net harvest, yellow bars represent line harvest).

Monitoring

Fisheries Queensland monitors school mackerel on the Queensland east coast to assess sustainability of stocks.

Our scientists collect biological information for key fish species (including length, sex and age of fish) to assess trends in stock levels.

  1. Fisheries Queensland has monitored recreationally caught school mackerel since 2013 by counting and measuring fish during boat ramp surveys.

Our scientists will start collecting length, sex and age information for the southern stock of school mackerel from commercially caught fish in January 2020. Sampling will mainly take place at seafood wholesalers and retailers, as well as at commercial fishers’ premises.

Skeletons of school mackerel caught by recreational fishers will also be collected from the southern stock as part of the Keen Angler Program.

Information collected will be combined with commercial harvest records and recreational harvest estimates to assess school mackerel stocks in routine assessments and periodic stock assessments.

How the information is used

Stock status

Fisheries Queensland combines monitoring information with commercial catch records and estimates of recreational harvest in a line-of-evidence assessment every two years using the Status of Australian Fish Stocks framework. The most recent assessment was completed in 2018 and is available at http://www.fish.gov.au/report/255-School-Mackerel-2018.

Stock assessment

Our scientists use harvest and biological information to estimate trends in stock abundance over time, and how stock abundance responds to changes in fishing pressure over time.

A 2019 stock assessment of east coast school mackerel found the southern stock was sustainable. It estimated that the current stock levels are around 65% of the original unfished population. The stock is therefore considered economically and environmentally sustainable, as the biomass is above the 60% target identified in Queensland Sustainable Fisheries Strategy: 2017–2027.

The assessment recommended starting biological monitoring of the commercial net fishery south of Mackay to improve the accuracy of future assessments.

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