American Oceans

Sierra Mackerel

The Sierra Mackerel, also known as the Spanish Mackerel, is scientifically known as Scomberomorus maculatus.

Spanish Sierra Mackerel Scomberomorus Maculatus off the coast

They have the general appearance of a mackerel, that slender silver body, along with differing markings. These fish can live for a little over a decade!

They live off the east coast of North America, though can venture down to Mexico if and when needed. They are predators themselves but are also prey to large fish and dolphins

Overall, these fish are fascinating creatures that follow the call of the wild, changing up their migration patterns to support reproduction and to search for warmer or cooler waters.

Characteristics & Appearance

When looking at a Sierra Mackerel, you find the expected silver-toned body, some spots for identifying markers, and thin fins. Their coloring changes depending on where you are looking at them from (top, side, bottom).

Weight & Length

The largest size of a recorded sierra mackerel was over 35 inches. On average, however, these mackerel usually reach up to 37 inches in length.

As for weight, they grow pretty quickly until they reach 5 or 6 years, and then they slow, though they end up weighing about 8-5 or 4-5 kg.

Physical Characteristics & Color

The Sierra Mackerel body shape has an elongated and somewhat oval or arrow-like body. The fins are small making them excellent for maneuverability and speed. The fins along most of the body are triangular, whereas the tail fin is caudal.

Sierra Mackerel with elongated and arrow-like body

The Mackerel’s coloring consists of a blend of colors. Towards the top of the body is a blueish color, then it goes to a greenish silver, and then moves to a lighter silver.

The sides of the fish hosts bronze or gold spots along the side. The coloring of the fins is darker than the rest of the body, being either a dark gray or black.

Looking down from above, the fish would blend into the water with its blue-green coloring. When you’re looking at it from underneath, their silvery color would blend in at the top, giving this mackerel an excellent ability to camouflage from predators.

Lifespan & Reproduction

Sierra Mackerel can live up to 12 years. Though on average they live about 8-10 years. These mackerels reach the ability to reproduce around two years of age.

The spawning season spans from April to September, near the coasts of North Carolina and Virginia. Some will choose to spawn near the Eastern portion of the Gulf of Mexico.

The fish have two genders, males who produce milt, and females who produce roe for reproduction purposes.

Fertilization happens externally by gametes being sent out into the water column, creating eggs that are round and buoyant.

Hatching occurs within about 25 hours at 79 degrees Fahrenheit. 0.12-0.51 inches is considered the larval stage for the Sierra Mackerel. These larval mackerels often use estuaries as safe nursery areas.


Sierra Mackerel are located mainly in two different areas around the coast of the eastern coast of the United States in the Atlantic and the Gulf of Mexico.

They can be found at depths ranging from 33-115 feet or 10-35 meters. They are schooling fish and tend to stay relatively close to the surface of the water.

During the spring and summer months, one portion of the population of the Sierra Mackerel goes north to the Atlantic ocean.

However, the second portion of the population migrates towards Florida during the fall and winter.

They can also be found in the Gulf of Mexico during the spring and summer, while they go south to the waters of Mexico as the waters get colder. 

Where Do Sierra Mackerel Live?

Sierra Mackerel are found in the subtropical and tropical waters off the eastern coast of North America.

Sierra Mackerel in tropical waters off eastern coast

There are two different areas where they are mainly found, which is why there are different migrating areas. But overall, these fish can be found schooling on the eastern coast of Noth America.

They spend most of the time hunting for food and avoiding predators such as tuna, dolphins, and fishing boats. They are daytime swimming fish, so they are more active during the day.

Food & Diet

The Sierra Mackerel is a carnivorous fish that eats mainly other smaller fish. However, they eat various smaller prey as well. Such as cephalopods and shrimp. Their diets also depend on their age, changing from birth to adulthood.

What Do Sierra Mackerel Eat?

As a predatory fish, the Sierra Mackerel is a carnivore. While they don’t branch out to eating things like humans, they are known to eat other smaller fish and other prey.

Their main source of fish they eat includes herring, menhaden, sardines, mullet, needlefish, and anchovy.

However, these fish also can hunt other prey. When they do branch out, though it is to a lesser extent, they eat things like shrimps, crabs, and squid.

To hunt, the Mackerel use their schooling to their advantage. Their hunting strategy is to trap, bring prey to the surface, and then eat.

To trap smaller fish inside of their schools, they create tight bundles so that it makes a basket or cage to contain their prey.

Then they begin to push the fish up towards the top of the water, so the smaller fish have nowhere to go.

After that, they begin to feed. This feeding process is a strategic and fascinating facet of these creatures. 

By using their schooling instincts, these fish can easily catch prey and provide plenty of food for themselves and those around them.

Threats & Predators

Main threats to this animal include humans because these fish are a targeted species for fisheries and recreational fishermen. As well as predators such as sharks and dolphins

Human Threats

Mackerel are in high demand for commercial seafood. They are also fished recreationally. However, there is a limit set for how many of these fish can be taken as well as a length requirement so that the population can stay strong. They are consumed fresh, frozen, smoked, and treated with antioxidants and preservatives.

Climate Change & Global Warming

Climate change and global warming is not a major threat to these fish. They stay happily near the coast in salty waters.

Their biggest threats consist of fisheries and natural predators. However, as a species of fish that is sought after by fishermen, the warmer the waters get, the more these fish swim to northern waters- changing their habits and causing fishermen to relocate their efforts.


Commonly, these fish are preyed upon by certain larger fish. This includes sharks and tuna. Sierra Mackerel are also fed on by bottlenose dolphins.

While these mackerels are juvenile, these fish are fed upon by immature dolphins and tuna. Being a schooling fish helps these fish to attempt to survive.  

Other Threats

These fish are highly prone to a variety of different parasites. Different areas of the fishes’ body would have different parasites.

For example, the muscle tissue is often infested with Kudoa Crumenacan. Other parasites documented include callitetrarhynshus graccilis, Pseudo Ceutorhynchus noodti, Otobothrium cysticum, Scomberocotyle scomberomori, Pseudaxine mexicana, Thoracocotyle crocea, and Lithidocotyle.

Conservation Status

This species is considered the least concern. This species is currently safe from being extinct. The population is stable thanks to conservation efforts.

There are also laws and regulations in place to keep this species of fish inside of the healthy population. Some sources say the population is over the set goal for this species.

Fun Facts About Sierra Mackerel

  • Mackerels have very small scales that can only be seen once the fish is caught and can be examined closely
  • The fish use the markings on their neighbors to figure out how fast or slow they need to go and adjust their speed accordingly.
  • Mackerel schools can stretch out for 20 miles
  • Female Mackerel can release 200,000 to 400,000 eggs in the water at a time
  • Mackerel eggs float because of the oily substance in them
  • Laravel Mackerel begin their lives by eating leftover yolk from their eggs before moving on to plankton and other sources of food.

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