Fisheries Queensland monitors key commercially and recreationally caught species to help assess the sustainability of Queensland's fisheries. Spotted mackerel (Scomberomorus munroi) has been monitored routinely since 2004, providing a long-term data series on the length, sex and age of fish being harvested.
The information collected through the monitoring program improves our knowledge of the harvest and increases our understanding of annual patterns and long-term trends in population characteristics. Fisheries Queensland uses these data sets, along with other information, to help assess the status of the spotted mackerel stock The most recent classification for spotted mackerel was sustainably fished.
Spotted mackerel is a species endemic to waters of southern Papua New Guinea and northern Australia. Multiple biological stocks are distributed across northern Australia from Rottnest Island on the west coast to Wollongong on the east coast.
Routine biological monitoring of spotted mackerel in Queensland focuses on the area south of Cairns to the Queensland - New South Wales border, where fish are known to belong to a single biological stock. This east coast stock undertakes annual migrations covering large distances. Schools move between spawning grounds in northern waters in winter/spring and southern feeding grounds in summer.
More than 50% of spotted mackerel harvested are between 65 ¬and 75 cm long (Figure 2). Few fish longer than 95 cm are observed in the harvest (Figure 2).
Small fish (60-70 cm) make up a higher percentage of the commercial catch than the recreational catch (Figure 2). This is a characteristic that has been observed throughout the history of the monitoring program.
One to five year-olds dominate the harvest of spotted mackerel (Figure 4). The oldest spotted mackerel aged in the monitoring program in 2013-2014 were 7 years old, the largest of which was 82 cm (approximately 3.3 kg). The largest fish aged in 2013-2014 was 103 cm and it was 6 years old.
How old is your fish?
Age-at-length graph for spotted mackerel. Measure the total length of your fish and estimate the age. For example a 70 cm male spotted mackerel would be on average 3 years of age.
Support and assistance
The monitoring team works closely with recreational and commercial fishers as well as fish wholesalers and retailers to collect biological information on spotted mackerel. Thank you to all these people and companies who have generously assisted with the monitoring of spotted mackerel by donating frames, providing length measurements or allowing Fisheries Queensland staff to measure their fish.
Want to find out more?
Phone 13 25 23, or email FisheriesMonitoring@daf.qld.gov.au