King mackerel, a migratory species in the Gulf of Mexico and western Atlantic Ocean, are medium-sized and a subtropical species. King mackerel are valued for commercial and recreational fishing.
While king mackerel can weigh up to 30 lbs., large fish have measured greater than 90 lbs. They grow fast, and can reach 5 and a half feet long. They have a lifespan of over 20 years and begin reproducing at age 2. King mackerel spawn in open water, and a female can have more than a million eggs.
This species is known for small, hard, loosely attached scales that cover its body. The body is streamlined with a tapered head, and there two dorsal fins separated by a deep notch. The lateral line starts high at the shoulder, drops sharply below the second dorsal fin, and continues to the tail. King mackerel have teeth similar to a bluefish. The teeth are sharp, closely spaced, and flat on one side.
King mackerel coloration varies by age. The backs of adults are olive, black, or blue-green with silver sides, while rose-colored iridescence covers the sides and fades to a white belly. Juvenile king mackerel have yellow-brown flank spots.
Not ones to miss meals, king mackerel are opportunistic carnivores. Diet varies by size and season. King mackerels eat a variety of fish, squid, and shrimp.
The king mackerel species prefers water temperatures between 66 and 85º F. The species migrates from the Gulf of Maine to Rio de Janeiro, Brazil. The fish are common in depths between 40 and 150 feet but can live in water from 115 to nearly 600 feet deep. Larger fish are found offshore, near inlets, and around harbors.
King mackerel migrate with seasonal changes in water temperature and food availability. When migrating, king mackerel travel in large schools.