fast schooling fish of the open coast

Size
Length: 30–50 cm, Weight: 300–800 g
Lifespan
10–15 years
Diet
Feeds on small crustaceans, zooplankton and small fish. Filters food from water using fine gill rakers. Hunts in large surface schools. Most active at dawn and dusk when prey abundance is highest.
Habitat
Coastal waters and open ocean from surface down to 200 metres depth. Prefers temperate waters with high plankton productivity. Often found near surface in large, fast-moving schools attracting seabirds.
Range
Found in coastal waters of North and South Islands from Northland to Stewart Island. Common off east coast of both islands and around Chatham Islands. Also found in Australia and Southwest Pacific.
Endemism
Native
Main Threats
Commercial trawl and purse seine fisheries are the primary threat. Also threatened by bycatch in hoki and squid fisheries. Climate change affects plankton populations. Potential overfishing occurs in some areas.
Population
Populations managed under New Zealand quota management system. Several jack mackerel species caught together in same fisheries. Stock assessments indicate stable populations for most species. Fishery certified sustainable by MSC.
Conservation Status
Not Threatened
A silver torpedo of the surface waters. This is a fish that moves in multitudes. It swims in enormous, fast-moving schools. These can be seen from the air as dark patches on the sea. Its flesh is oily and strongly flavoured. It is not popular for eating fresh. Instead, it is used as bait and in pet food. The Māori name Haature refers to its habit of swimming near the surface in large numbers. Several different jack mackerel species live in New Zealand waters. It is a fish that is more useful dead than alive. The body is elongated and streamlined, with a small head and a terminal mouth. Colour is silvery blue-grey on the back, fading to silver on the belly. The fins are dusky. Scales are small and rough. The tail is deeply forked, built for speed. It was designed for the chase. It is a filter-feeder. It strains small crustaceans and zooplankton from the water using fine gill rakers. Feeding is most active during dawn and dusk. This is when prey is most abundant. Enormous schools swim together, sometimes covering hectares of ocean surface. The schools are fast-moving. They can change direction instantly. From above, they appear as dark patches on the water. From below, the shimmer of thousands of silvery bodies creates a moving, liquid mirror. Its flesh is oily and strongly flavoured. It is not popular for eating fresh. It is used as bait for larger fish and in pet food. It is also processed into fish meal. To see one is to see a silver school in the surface waters. The ocean is blue. The school moves as one, a dark patch on the water, a liquid mirror from below. The kingfish are underneath, waiting. The jack mackerel do not know. They just want to eat zooplankton. They are good at it. That is why the kingfish are there.