Spanish Mackerel vs King Mackerel – What’s The Difference?


Spanish mackerel and king mackerel have many similarities. For this reason many people ask about their differences or if they’re the same. Let’s answer, is king mackerel the same as Spanish mackerel?

King mackerel and Spanish mackerel are not the same, they are different species although from the same family and genus. Spanish mackerel is the S. maculatus species, king mackerel is the S. cavalla species. King mackerel are found in deeper water, near Brazil and the Indian Ocean where Spanish mackerel aren’t found.

This article will compare their tastes, textures, cooking methods, costs, mercury levels and whether one can substitute for the other in recipes. In addition, I’ll do a side-by-side comparison of their habitats, appearance and compare their nutritional value.

Keto Bread Tip: Great News! Did you know, you don’t have to give up your favorite bread, pizza or sandwiches to follow a 100% Keto diet. Find out more in the KetoBreads website by clicking here, Keto Breads.

Disclaimer: The above link and others in this article are affiliate links which means I may earn a small commission at no extra cost to you. As an Amazon associate I earn from qualifying purchases.

Spanish Mackerel and King Mackerel: Habitats, Size, Weight and Appearance

When someone is shopping in the fish market for fresh, whole fish or catching a mackerel in the water, it may not be immediately obvious which kind of fish they’re looking at. For this reason, we want to find out a simple method for identifying which fish is which.

How can you tell a Spanish mackerel from a king mackerel?

To tell the difference between a Spanish mackerel and a king mackerel is to check their front dorsal fin and lateral body line. Spanish mackerel have a dark spot on the front of the first dorsal fin which king mackerel doesn’t have. The lateral line on a Spanish mackerel gently slopes down while king mackerel’s line sharply lowers a half way down the body.

Other ways to tell the difference between a Spanish mackerel and a king mackerel are:

  • Adult Spanish mackerel have yellow spots on the sides. Adult king mackerel don’t have spots on their sides.
  • Spanish mackerel are smaller and weigh less. Adult Spanish mackerel may grow up to 13 pounds while king mackerel can grow up to 40 pounds. Therefore, a mackerel over 20 pounds is more likely a king mackerel.
  • King mackerel may be found near Brazil or in the Indian Ocean where Spanish mackerel won’t be found.

It’s important to note juvenile king mackerel, under 10 pounds have yellow spots on their sides which may make one think it’s a Spanish mackerel. Always check the slope of the lateral line and the front dorsal fin to help distinguish between the two fish.

Spanish Mackerel and king mackerel comparison

Spanish mackerel and King Mackerel Scientific Classifications, Families, Species

Spanish mackerel are from:

  • Family: Scombridae
  • Genus: Scomberomorus
  • Species: S. maculatus
  • Common nicknames: Spotted mackerel, spotted cybium.

King mackerel are from:

  • Family: Scombridae
  • Genus: Scomberomorus
  • Species: S. cavalla
  • Common nicknames: Sierra, cavalla, kingfish.

Spanish and king mackerel are from the same family and genus but are different species.

Spanish Mackerel and King Mackerel Habitats

Spanish mackerel habitats

  • Spanish mackerel are found off the Atlantic Ocean coast of the United States and in the Gulf of Mexico. They are far north as Massachusetts and south down to Florida.
  • Spanish mackerel prefer shallow waters and sand bottoms in depths from 10 to 40 feet.

King mackerel habitats

  • King mackerel are found off the Atlantic Ocean coast of the United States, the Gulf of Mexico and South America. They are as far north as Maine and south past Florida down to Brazil. They are also found in the Indian Ocean and the coast of India.
  • King mackerel can be found in deeper waters from 40 to 590 feet deep.

Spanish and king mackerel are both found along the eastern coast of the U.S. and in the Gulf of Mexico. Spanish mackerel prefer more shallower water than king mackerel.

spanish mackerel and king mackerel comparison photo
(top & middle) King mackerel
(bottom) Spanish mackerel

Spanish Mackerel and King Mackerel Appearance

Spanish and King Mackerel Colors

  • Spanish mackerel have a greenish back, silver sides and belly. Spanish mackerel have yellow or olive green spots on their sides.
  • King mackerel have an olive back, silver sides and white belly. Younger king mackerel, under 10 pounds, have yellowish-brown spots on their sides which fade as they grow older and bigger.

Spanish mackerel have a silver belly. King mackerel have a whiter belly. Adult Spanish mackerel have yellow spots, and king mackerel only have yellow spots when they’re a juvenile.

Dorsal Fins

  • Spanish mackerel has two dorsal fins. The front dorsal has about 15 spines and the front is taller than the rear. The second dorsal has about 15 soft rays.
  • King mackerel has two dorsal fins. The front dorsal has about 15 spines and the front is taller than the rear. The second dorsal has about 15 soft rays.

The front of the Spanish mackerel first dorsal fin is black. The front dorsal fin on the king mackerel is colorless or lightly colored throughout the whole fin.

Anal Fins

  • The Spanish mackerel has one anal fin having soft rays with no spines.
  • The king mackerel has one anal fin having soft rays with no spines.

Spanish and king mackerel only have soft rays on their one anal fin.

Tail Fins

  • The Spanish mackerel tail fin is forked.
  • The king mackerel tail fin is forked.

Spanish and king mackerel have a deeply forked tail fin resembling a boomerang.

Mouth

  • The Spanish mackerel mouth is large but doesn’t extend past the eye line. Spanish mackerel have a single row of cutting edged teeth on both jaws.
  • The king mackerel mouth is large but doesn’t extend past the eye line. King mackerel have a single row of cutting edge teeth on both jaws.

Spanish and king mackerel have sharp teeth inside their mouth on the lower and upper jaws.

Body Shape

  • The Spanish mackerel body is long, slender and tapers narrower towards the tail fin.
  • The king mackerel body is long, slender and tapers narrower towards the tail fin.

Spanish and king mackerel have a long, narrow body which tapers towards the tail.

Distinguishing Marks

Spanish Mackerel

  • Spanish mackerel have a lateral line on the sides from the rear of the gill cover to rear. The lateral line begins higher and gradually slops down towards the middle of the body towards the tail.
  • Spanish mackerel have a dark spot at the front of the first dorsal fin.
  • Spanish mackerel have yellow spots on their sides.

King Mackerel

  • King mackerel have a lateral line on the sides from the rear of the gill cover to rear. The lateral line begins higher and drops sharply half way down the length of the body and continues in the middle towards the tail.
  • King mackerel juveniles, under 10 pounds, have yellowish spots on their side which fade as they grow.

Scales

  • The scales on the Spanish mackerel are tiny.
  • The scales on the king mackerel are tiny.

The scales on the Spanish and king mackerel are small.

Spanish Mackerel and King Mackerel Size and Weight

  • Spanish mackerel averages 19-33 inches long and weighs up to 13 pounds. The females grow longer and weigh more than the males.
  • King mackerel can grow to 30-50 inches long and weigh up to 40 pounds or more.

King mackerel weigh much more than Spanish mackerel and can grow 50% or more longer.

Spanish Mackerel and King Mackerel Lifespan

  • Spanish mackerel lives up to 12 years.
  • King mackerel lives up to 20 years.

Diet

Spanish mackerel consumes the following:

  • Small fish
  • Anchovies
  • Shrimp
  • Squid
  • Herring
  • Menhaden
  • Alewives

King mackerel consume the following:

  • Squid
  • Menhaden
  • Clupeidea
  • Cutlessfish
  • Striped anchovies
  • Minnows
  • Northern mackerel
  • Blue runners

Mackerel and other fish are known for being a part of many diets like keto or heart healthy.

If you’re eating low-carb or want to give keto a try, many of my clients have followed this 28-Day Keto Challenge with great success. Visit their website and check it out.

Species Resources 1 2 3 4 5 6 7 8 9 10

I recently published an article comparing Cero Mackerel and Spanish Mackerel. You can check it out here, Spanish Mackerel vs Cero Mackerel – What’s The Difference?

spanish mackerel and king mackerel photo
Adult Spanish mackerel or juvenile king mackerel? Always check the lateral line.

Spanish Mackerel and King Mackerel: Tastes and Textures

One of the main reasons people chooses a particular fish to eat is its taste and texture. When comparing the two fish, does Spanish mackerel taste like king mackerel?

Spanish mackerel and king mackerel have a similar medium flavor taste. Their flavor is not considered mild or sweet. Spanish mackerel and king have an oily flesh but Spanish mackerel is a little more oily than king mackerel due to its higher fat content. Both mackerel have a similar firm texture which breaks apart into small flakes. 

What does Spanish mackerel taste like? Spanish mackerel have a medium taste. The fish is slightly oily due to its high fat content. The texture is firm and breaks apart into small flakes.

What does king mackerel taste like? King mackerel have a medium taste. The flesh is slightly oily due to its fat content. The texture is firm and flaky. 

If you’re interested in the differences between a king mackerel and an Atlantic mackerel, check out my article, King Mackerel vs Mackerel: What’s The Difference? We Compare.

Spanish Mackerel and King Mackerel Substitutions

When preparing recipes for dinner you may have one fish already in the refrigerator ready to be used. In addition, it’s not always possible to locate the type of fish called for in the recipe. If you have some Spanish mackerel, you may ask, can I substitute Spanish mackerel for king mackerel?

Spanish mackerel and king mackerel can substitute for each other due to their similar medium flavors. Their firm textures are similar allowing both fish to be cooked using similar cooking methods. Spanish mackerel and king can be cooked by grilling, searing, frying, broiling or baking. 

Other Spanish mackerel substitutes include the following:

  • Tuna
  • Bass
  • Northern pike
  • Catfish
  • Bullhead
  • Salmon

The king mackerel substitutes are:

  • Bass
  • Northern pike
  • Tuna
  • Bullhead
  • Salmon
  • Catfish

When substituting Spanish or king mackerel always stick to the following:

  • Same size and weight.
  • Stick with similar fillets, whole fillet or cross section.
  • Stick with skinless or skin when the recipe calls for one.
  • Texture is more important for certain cooking methods. Like using a firmer texture when grilling 11.

How To Cook Spanish Mackerel

The most popular ways to cook Spanish mackerel include:

  • Grilling
  • Frying
  • Searing
  • Broiling
  • Baking

Spanish mackerel flavor pairings:

  • Olive oil
  • Lemon
  • Smoked paprika
  • White wine
  • Cajun

Find out what mackerel taste people preferred, Atlantic or Spanish, in my article, Atlantic Mackerel vs Spanish Mackerel – Are They The Same?

How To Cook King Mackerel

Foods For Anti Aging do not recommend consuming king mackerel due to their high mercury levels. Please see the mercury section down further in this article. 

Even though, some people still enjoy eating king mackerel and try to use the smaller ones which probably contain less mercury. Some people may find king mackerel a little fishy therefore the preparation is important.

Many people soak the fish in icy water, rinse the fillets and soak the fish again. Repeat this process until the flesh of the fish and the water become clearer. 

Popular ways to cook king mackerel:

  • Grilling
  • Broiling
  • Searing
  • Frying
  • Baking

Flavor pairings for king mackerel:

  • Lemon juice
  • Olive oil
  • Italian dressing
  • Smoked paprika
  • Cajun
  • White wine

How Much Spanish Mackerel and King Mackerel Cost

The costs for fresh fish will vary depending on how the fish are caught and where they are sold. When purchasing any fish, be sure to check the label to see if it is wild-caught or farm raised. Therefore, which fish costs more, Spanish mackerel or king mackerel?

Spanish mackerel fillets cost more than king mackerel fillets per pound. The average cost for Spanish mackerel fillets is $19.98 per pound. The average costs for fresh king mackerel fillets are $18.97 per pound.

I checked the Fulton fish market online for prices:

  • Wild king mackerel fillet
    • $18.97 per pound
  • Wild Spanish mackerel fillet
    • $22.40 per pound

I also checked Citarella online for prices:

  • Spanish mackerel fillet
    • $20.56 per pound

I checked Fresh Direct online and found the following prices:

  • Wild Spanish fillet
    • $16.99 per pound

To save some money on fresh seafood, would you believe some can be purchased on Amazon? Check out their current prices and selection, Fresh Seafood.

Spanish Mackerel and King Mackerel Nutrient Comparison

Below is a nutrient comparison of Spanish mackerel and king mackerel per four ounces:

Nutrient King mackerel, raw (4 Ounces) Spanish mackerel, raw (4 Ounces)
Calories 119 158
Fat 2.3 g 7.1 g
Saturated Fat 0.4 g 2.1 g
Cholesterol 60 mg 86 mg
Protein 23 g 22 g
Omega-3 0.37 g 1.64 g
B-6 0.5 mg 0.4 mg
B-12 17.6 mcg 2.7 mcg
Thiamin 0.11 mg 0.14 mg
Riboflavin 0.54 mg 0.19 mg
B5 0.9 mg 0.8 mg
Iron 2.0 mg 0.5 mg
Niacin 9.7 mg 2.6 mg
Folate 9.0 mcg 1.1 mcg
Potassium 493 mg 505 mg
Magnesium 36 mg 37 mg
Phosphorus 281 mg 232 mg
Calcium 35.1 mg 12.4 mg
Zinc 0.6 mg 0.5 mg
Selenium 41.3 mcg 41.3 mcg

Nutrient Resources 12 13 14 15

Both fish contain a wide variety of similar nutrients. Spanish mackerel contains more of some nutrients while king mackerel contains more of others. Which is healthier, Spanish mackerel or king mackerel?

Spanish mackerel is healthier than king mackerel due to its higher percentage of omega-3 fatty acids, minerals and lower levels of mercury. The FDA recommends avoiding king mackerel due to its high mercury levels. Spanish mackerel provides more, B1, potassium and magnesium than king.

It’s unfortunate king mackerel contains a high level of mercury because it also provides many beneficial nutrients. King provides more B6, B12, riboflavin, B5, niacin, folate, phosphorus, calcium and zinc.

In addition, king mackerel contains less calories, total fat, saturated fat and cholesterol than Spanish mackerel.

I also compared Atlantic Mackerel and Pacific Chub Mackerel in a recent article. Find out which mackerel tasted better in my reader poll, Atlantic Mackerel vs Pacific Chub Mackerel: The Differences.

Spanish Mackerel Health Benefits

B Vitamins

The B vitamins provided by mackerel include the following:

  1. B1 (thiamin)
  2. B2 (riboflavin)
  3. B3 (niacin)
  4. B5
  5. B6
  6. B9 (folate)
  7. B12

B vitamins help support the following:

  • Nerve function.
  • Digestion.
  • Brain function.
  • Energy levels.
  • Red blood cells.
  • Cardiovascular disease.

Omega 3 Fatty Acids

Spanish mackerel provides 1.64 grams of omega-3 fatty acids per four ounces. The fatty acids provided help keep arteries healthy and are considered heart healthy. The omega-3s may help with the following:

  • Help keep the heart rhythms more regulated.
  • Lowering triglycerides.
  • Reduce inflammation.
  • Reduce plaque buildup.
  • Keeping bad cholesterol low.
  • Keeping good cholesterol high.

DHA and EPA, two of the fatty acids, are associated with lowering blood pressure and improving the health of blood vessels 16.

Studies suggest omega-3s boost the effectiveness of anti-inflammatory drugs. In addition, they’ve been shown to help reduce joint pain and stiffness in people with rheumatoid arthritis.

Potassium

Spanish mackerel provides 505 mg per four ounces. Potassium helps the body get rid of excess sodium which helps reduce fluid build-up. The result keeps systolic and diastolic blood pressure lower 17.

The more potassium you consume, the more sodium your body will lose. Consuming too much sodium or not enough potassium throws off the delicate balance the kidneys need to remove the excess water 18.

According to Harvard Health, a number of studies have shown a connection between low potassium levels and increased blood pressure 19.

Calcium

Calcium which Spanish mackerel provides is important for blood pressure and the heart.

Harvard Health reports calcium helps maintain blood pressure because it helps to control the relaxing and tightening of blood vessels 20.

Calcium also helps the following:

  • Build and maintain strong bones.
  • Muscles need calcium to function properly.
  • Improve nerve function.

Selenium

Selenium is a nutrient which doesn’t receive much press. I’m unsure why many people don’t write about it more. Many studies 21 show selenium may help to protect the following:

  • Cognitive issues
  • Heart disease
  • Thyroid
  • The immune system

Magnesium

Spanish mackerel provides 37 mg of magnesium per four ounces. It helps to calm and relax the whole body including blood vessels. It has been shown to help improve sleep related problems like insomnia 22.

Magnesium helps keep blood pressure levels balanced and stable. A recent study researched 22 studies and concluded magnesium supplementation decreased diastolic and systolic blood pressure 23.

Magnesium helps control muscle and nerve function, blood sugar and blood pressure.

In the muscles and heart, magnesium competes with calcium to help the muscles relax after contracting. When the body is low in magnesium, calcium can over stimulate the heart muscle’s cells causing a rapid or irregular heartbeat.

Spanish Mackerel and King Mackerel Mercury Levels

The EPA and The Food and Drug Administration have issued warnings and suggestions regarding mercury levels in fish and how often they should be consumed 24. This is especially important for the following:

  • Pregnant women
  • Developing children
  • Young infants

They established a list of the following:

  • Best fish
  • Good choices
  • Fish to avoid

Therefore, does Spanish mackerel or king mackerel have more mercury?

King mackerel has more mercury than Spanish mackerel. Spanish mackerel is listed on the FDA’s good choices of fish regarding mercury levels. King mackerel is listed on the FDA’s choices to avoid list. 

If you’re pregnant, breast feeding or has a young child, Always check with a physician prior to eating new foods or changing your dietary habits.

If you’re consuming fish from the best list, The FDA recommends eating two to three servings per week total for adults. From the good choices list, they recommend eating them once per week.

Mercury warnings can change over time or affect only a particular area or state. Please check with your local EPA and FDA for the current recommendations 25.

Another Mackerel vs Mackerel article I recently published, Chub Mackerel vs Jack Mackerel: What’s The Difference?

Read Next – More Fish vs Fish Articles!

Walleye vs Cod – What’s The Difference? Let’s Compare Them

Rock Bass vs Green Sunfish – Are They The Same? We Compare

Sea Bass vs Cod – Is One Better? Let’s Compare

Pacific Cod vs Sockeye (Pacific Salmon) Which Is Better?

Tuna vs Mahi Mahi – What’s The Difference? Let’s Compare

 

Article Resources: Foods For Anti-Aging follows strict guidelines to ensure our content is the highest journalistic standard. It's our mission to provide the reader with accurate, honest and unbiased guidance. Our content relies on medical associations, research institutions, government agencies and study resources. Learn more by reading our editorial policy.
  1. Wikipedia: Spanish mackerel[]
  2. NOAA Fisheries: Spanish Mackerel[]
  3. Delaware.gov: Spanish Mackerel[]
  4. Maryland Department of Natural Resources: Spanish Mackerel[]
  5. Wikipedia: King mackerel[]
  6. NOAA Fisheries: King Mackerel[]
  7. Delaware.gov: King Mackerel[]
  8. Florida Fish and Wildlife Conservation Commission: King Mackerel[]
  9. Sea Grant Louisiana: King Mackerel[]
  10. North Carolina Environmental Quality: State urges fishermen to learn the difference between king mackerel and Spanish mackerel[]
  11. Sea Grant North Carolina: Fish Flavors and Substitutions[]
  12. Nutrition Value: Fish, raw, Spanish, mackerel[]
  13. Nutrition Value: Fish, raw, king, mackerel[]
  14. USDA: Fish, mackerel, king, raw[]
  15. USDA: Fish, mackerel, Spanish, raw[]
  16. National Center for Biotechnology: Marine Omega-3 Supplementation and Cardiovascular Disease[]
  17. American Heart Association: How Potassium Can Help Control High Blood Pressure[]
  18. National Center for Biotechnology Information: The Effect of the Sodium to Potassium Ratio on Hypertension Prevalence: A Propensity Score Matching Approach[]
  19. Harvard Health: Potassium lowers blood pressure[]
  20. Harvard Health: Key minerals to help control blood pressure[]
  21. National Institutes of Health: Selenium[]
  22. National Institutes of Health: Magnesium[]
  23. National Center for Biotechnology Information: Effect of magnesium supplementation on blood pressure: a meta-analysis[]
  24. FDA: Advice about Eating Fish[]
  25. National Center for Biotechnology Information: Mercury accumulation in largemouth bass (Micropterus salmoides) in a Florida lake[]

Kevin Garce

Kevin Garce is a Certified Health Coach who encourages people by informing them on nutrition and food topics important to them. His years of research and knowledge inspire people to achieve their goals. Read more here About Me

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