Chilean jack mackerel

What it is

This species belongs to the jack mackerel genus within the Carangidae family. It has an elongated body that is compressed from side to side. The head is large with transparent membranes protecting the eyes. The mouth is wide, with the lower jaw reaching the front of the eye. Small teeth line the jaws. The second dorsal fin is much longer than the first, and the pectoral fins are pointed. The upper body shines metallic blue, while the belly is silvery white. Adults usually measure 45 cm but can reach 70 cm.

Where it lives

These fish inhabit the epipelagic zone, swimming near the surface in coastal waters and the open ocean. They typically stay between 10 and 70 metres deep but can dive to 300 metres. Their range covers the south Pacific, including waters off Chile and Peru, around New Zealand and southern Australia. A broad band across the open ocean, known as the jack mackerel belt, connects these areas. This belt spans latitudes 35 to 45 degrees south. Spawning groups move north of 40 degrees south in spring and summer, shifting south in autumn and winter to feed.

How it lives

Chilean jack mackerels form large schools. They feed primarily on fish larvae, shrimp, copepods and other small crustaceans. Squid and small fishes also form part of their diet. Predators include albacore tuna and swordfish, which have been found with them in their stomachs. Other large predators like billfish and sharks likely hunt them too. These fish can live for up to 16 years. They migrate seasonally, following food sources and spawning grounds across the vast south Pacific region.

Breeding and life cycle

Spawning occurs mainly during the summer months. The fish release pelagic eggs, which float freely in the open sea rather than sinking or attaching to surfaces. Stock structure remains uncertain, but scientists propose four separate stocks. These include distinct groups off Chile and Peru, a central Pacific group in high seas, and a southwest Pacific group straddling New Zealand and Australian zones. Spawning concentrations shift latitude with the seasons, moving north in warmer months and south in cooler periods.

Fish and people

This species is a major commercial catch, often processed into canned goods or sold fresh. It is a staple food in parts of Africa. Large quantities are turned into fishmeal to feed swine and farmed salmon, requiring five kilograms of mackerel for one kilogram of salmon. Fisheries in Chile and Peru dominate the catch, with significant activity also in New Zealand and Australia. Historical overfishing by distant water fleets caused stock declines. Recent regional management efforts have helped populations recover towards 1990s levels.

Status and threats

Concerns about collapse arose after biomass dropped significantly between 2006 and 2011. Scientists warned that catches needed to fall below 390,000 tons to allow rebuilding. Geopolitical disputes hindered early regulation attempts. However, the formation of the South Pacific Regional Fisheries Management Organisation in 2013 improved oversight. By 2019, indicators showed increasing abundance and better catch rates. The population trend is now estimated to be rising, with spawning biomass expected to grow.

Questions people ask about Chilean jack mackerel

Good reading and sources

• In Mackerel's Plunder, Hints of Epic Fish Collapse (Published 2012)The New York Times, Article

• Chilean jack mackerel on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data