Pacific Chub Mackerel
Scomber japonicus

Physical Description

  • A medium-sized, slender, football-shaped fish
  • A pointed head and a large mouth
  • Dark blue on back, silver on the belly, mottled with small dusky blotches on the top
  • A pointed dorsal fin resembling that of related species


  • Southeastern Alaska to Mexico
  • Most common south of Point Conception, California


  • The open ocean within twenty miles of shore
  • Juveniles live off of sandy beaches, in open bays, and around kelp forests
  • Adults live near shallow banks, from depths of 0 to 1000 feet


  • As juveniles, they feed mainly on copepods and rotifers and larval anchovies and sardines
  • Sometimes even eat smaller larvae of their own kind!
  • As adults, they feed on mysids and euphausids.


  • Large fish, sharks, tunas, marine mammals, seabirds
  • Humans¬†

Interesting Facts

  • Fossils of this fish have been found in the Pliocene of Italy (from 3 to 2.2 million years ago)!
  • Chub mackerel larvae can consume up to 87% of their dry body weight a day!
  • They often school in large schools for defense, including with sardines and jack mackerel.

Sources: Diet of Larvae(n.d.). Retrieved April 21, 2013, from; Paleobiology Database; NOAA Fisheries; NOAA Fishwatch

Photo: Kevin Lee

Are you a fourth through twelfth grade teacher and want your students to learn more about mackerel? Book a Fish Dissection Discovery Lab at Birch Aquarium!


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