Sushi with Fish Eggs | what is the roe on top called and is it healthy?

by Joost Nusselder | Updated on:  May 28, 2020

What makes sushi great is that it is made from a combination of a variety of ingredients that although by themselves individually may not taste good, but will absolutely delight your palate when eaten together.

One key ingredient that embellishes any sushi dish is fish eggs. That’s why I wanted to write this in-depth post on sushi with fish eggs.

Sushi with fish eggs

Whether it’s the

You can bet it will not only make the sushi more attractive but taste great as well.

Today we will be talking about those nice-looking little fish eggs that you often see in your sushi.

Find out what they are, how they are being harvested and how chefs prepare them.

What are Those Fish Eggs on Sushi?

What is the orange stuff on my sushi?

What are the little balls on top of sushi?

Whether it is placed on top of the nigiri like a cluster of tiny red or orange gelatinous spheres or sprinkled generously on top of various sushi rolls, fish roe is among the most important ingredients in Japanese restaurants.

What are the orange fish eggs on sushi

Fish roe is very similar to other egg types and it is rich in protein and other vitamins, unfortunately, it also has a high content of cholesterol.

What type of roe is used in sushi

Those who are knowledgeable in the culinary world may know that chefs use only 3 types of fish roe in nearly all sushi bars and restaurants:

  1. Tobiko (とびこ, flying fish roe)
  2. Masago (真砂子, smelt roe)
  3. Ikura (イクラ, salmon roe)

Roe is fully ripe eggs from fish and other marine animals.

What is the Japanese name for fish eggs?

When you ask people the name for fish eggs in Japanese, you’ll most often hear Tobiko (とびこ) which is flying fish roe and most commonly used on sushi. It is the name for this particular type of fish eggs and not a general name like we use roe to describe eggs from all types of fish.

In culinary circles, roe is considered a dish or garnish for various dishes that come from fish and other aquatic life.

The chef can prepare the roe in a few different ways, depending on the fish/aquatic egg type and which flavor may suit them.

Is fish roe in sushi raw?

Chefs can use roe both ways – fresh or cooked. Even though there are many dishes that use cooked roe, the Tobiko, Masago or Ikura fish roe on sushi is almost always served raw.

Is Tobiko safe to eat?

Eating tobiko roe is good for your health just as long as you consume it moderately (eating too much of it might increase your cholesterol). According to the US Department of Agriculture fish roe is rich in proteins and amino acids, but low in calories and it is abundant in minerals and nutrients such as magnesium, selenium, and vitamin B-12.

Which are very beneficial to your health; however, the amount and availability of them may vary from the various roe types.

The unsaturated fatty acids known as Omega-3, which is good for the heart is also present in fish roe.

Omega-3 fatty acids have anti-inflammatory properties that can help protect your body (especially your brain) from oxides that can cause harm at the molecular level.

A peer-reviewed scientific journal called the Journal of Food Science and Technology included new research that discovered that roe has a high amount of fat that helps the brain to improve its learning ability and also reduce the fats in a person’s bloodstream.

Also read: is sushi always raw fish?

How do they get fish eggs for sushi?

Fish eggs of roe come from fish and other animals in the ocean and if you’ve seen them up close, then you would know that they’re roughly 1-2 mm in size.

Harvesting them from the fish or other sea animals will be a challenge as going by the process means that you must first catch the fish before you can harvest the fish roe, then preserve it, ship it to the restaurant, and finally prepare and serve it to the guests.

However, the actual process of harvesting the roe may not be exactly as you have expected, so here’s how they really do it.

What kind of fish is roe?

This is still a commonly asked question but by now you might know from this article that roe is not actually a fish, it’s the eggs of the fish and roe is used to describe the fish eggs from different types of fish like salmon or sturgeon.

Are fish killed for caviar?

Unfortunately, the answer to this question is a disappointing “yes,” and while preserving our natural resources is a primary concern, especially during these times where the clamor for climate change is at its loudest, fishermen have a good reason why they do it.

Despite the modern techniques in harvesting caviar, which are in fact, designed to keep the fish alive after harvesting their roe, it still doesn’t compare with the quality and consistency of the roe harvested from the fish that’s been killed.

Continue reading this article to find out why fishermen need to kill the fish in order to harvest the roe and discover the various ways we get this precious resource in the ocean.

How is roe harvested and made into caviar?

Fish roe is harvested by using 2 special methods before they are made into the caviar delicacy that you know and love.

The Classic Harvesting Method

The classic method to harvest roe has been around since ancient times and it is still done the same way to this day.

Even though scientific advances have been made in the areas of farming, fishing and production technology, the general practice of harvesting roe has remained the same, and the step-by-step process that people used centuries ago has been handed down to their descendants up until the recent times.

The PETA organization alongside many other animal rights activist movements are criticizing the traditional Russian and Iranian roe harvesting technique and deemed it inhumane and cruel to animals.

This happened after marine biologists confirmed that the wild sturgeon populations have been steadily declining and they might face extinction soon.

The reason why animal rights activists protest this method so much is because it requires that the sturgeon, or other fish to be killed off in order to harvest its eggs in the best possible condition.

In modern fish farms and fisheries, the female fish species that carry the roe is placed in ice-cold waters in order to minimize their movement until they become unconscious and completely immobilized, then their roe will be harvested.

Only purified water is used to clean the fish and then an incision is made in the length of the belly of the fish.

Most fish have two roe sacks.

The handlers remove the fish eggs before the fish has completely died.

If they delay the extraction of the roe, then the dead fish will release a chemical that will otherwise harm the eggs rendering it useless.

After the egg sacks are removed from the fish, they are cleaned and placed in a container to be shipped to sushi restaurants later on, while the fish is processed for meat harvesting.

Each individual roe sack (or skein if it comes from salmon or trout eggs), is filtered through a sieve in order to do away with the membrane and keep only the fish eggs.

Once the membrane has been separated from the fish eggs, then they are washed and filtered again (they look like tiny green eggs), then they are set aside to let drain any moisture left and weighed, salt-cured and graded.

The Humane Harvesting Method

A new method of harvesting fish roe that’s safer than the classic method – one that allows handlers to get the roe without killing the fish – and it’s called the Humane Harvesting Method.

This fish farming technology is sometimes called “anti-cruelty,” or “no-kill” caviar and it uses hormone therapy combined with milking techniques, as well as basic surgery in order to harvest the fish roe without killing the fish.

This allows fish farmers to harvest fish eggs from the fish in the tanks multiple times and not have to worry to catch or buy new fish unlike with what they do in the classic harvesting method.

It is unfortunate that all unfertilized mature eggs are inedible as soon as they are removed from the mother fish’s sack and get contaminated by the water (whether salty or fresh), and this is due to the network of cells that keeps the fish roe stable while in the sack.

This also decreases its quality and is no longer viable for making caviar.

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This is the reason why the traditional harvesting method for fish roe requires the mother fish to be killed off, in order for the fish farmer to get the fish eggs from the egg sack while they are still immature.

Recently an altered fish breeding reproduction method was invented by a German marine biologist; Angela Köhler (known for introducing the Köhler process, which is a modified fish-milking method that is now being used in the caviar industry) allows fish farms to harvest fish roe to make caviar without harming the mother fish.

The Köhler process is done by injecting the ovulating fish with a protein or hormone that is a similar naturally-occurring chemical, which separates the egg sack membranes from the fish eggs in the belly cavity of the mother fish.

The same process happens in the natural pregnancy cycle of the fish right before the eggs are delivered.

If the fish farmer will sense that the fish might suffer some potential stress during the process, then they may put it on ice or sedate it to not damage the fish roe while it is being harvested.

How the Fish Eggs are Removed

The fish is rinsed with purified water and the eggs are harvested by either of these 2 ways:

  1. C-Section Method: A tiny incision is cut on the belly of the female sturgeon and then the eggs are meticulously scooped out. After this meticulous process, the fish is patched up and be allowed to regain consciousness. The only downside to this method is that the sturgeon is going to be vulnerable to infections, and their reproductive organs might get damaged as a result of the surgery.
  2. Vivace Method: This method does away with invasive/intrusive ways of extracting the fish roe and instead utilizes a fish-milking technique known as striping, which only requires someone to massage the eggs out of the fish (this is very similar to when the fish goes through natural delivery).

The fish eggs are then immediately rinsed in a water-calcium solution after milking them from the pregnant mother fish.

This is done so that the fish eggs’ texture will be ensured to be of the highest quality and will not turn into mush.

This allows for the green roe to be able to withstand further handling, salting, and curing.

The green fish roe is then tested to see if they are firm enough to go through more process along the production line, and then they’re washed and filtered.

Then they are drained in order to remove as much water as possible, then they are weighed, salt-cured and graded.

Even though the classic method of harvesting fish roe has been historically considered the standard practice in making caviar more than the humane method, the anti-cruelty method is more appealing to animal rights activists as it is more efficient and it helps sustain endangered species of sturgeon.

It takes about a decade before sturgeons are old enough to undergo fertilization, furthermore, their eggs can live for almost a century, and therefore it’s only logical to keep them alive to extract their eggs for a much longer time.

In addition to saving the flora and fauna of this planet, keeping the same female fish to produce eggs to harvest seasonally is also cost-effective for fish farms.

Despite the potential benefits of utilizing the humane method in harvesting roe, most fish farms still use the classic method.

This may be due to the lack of information being disseminated across the fishing industry and/or people still prefer the classic method.

The no-kill method of harvesting caviar also requires fish farms to invest in hormones, chemicals, and equipment that’s necessary to perform a seamless operation.

Unfortunately, fish farmers look at this as a financial liability, which also makes them prefer to use the classic method instead.

If conservationists and animal rights activists deem traditional caviar as inhumane and unethical, then the same is true certain people, such as pregnant women, will have to say “no” to no-kill caviar due to the hormones and/or proteins used to extract the roe.

Different Types of Fish Eggs

Tobiko (flying fish roe)

Tobiko is the Japanese word for flying fish roe.

Tokibo fish eggs are small measuring between 0.5 to 0.8 mm in diameter and they possess a red-orange color, salty/smoky flavor, and are crunchy to the bite.

It is commonly found in California rolls sushi, but it is also used in making sashimi as a garnish.

Masago (smelt roe)

Smelt roe, or as the Japanese call it, Masago – are the caplin fish’s edible eggs commonly used in making sushi and sashimi.

Marine biologists have classified them as forage fish, which are considered prey to larger predators like codfish, seabirds, seals, and whales.

These small, silvery-green fish closely resemble sardines.

Capelin is an edible fish just like most other known fish species; however, fishermen want it for its eggs or roe more than any other reason.

About 80% of the capelin fish caught is used to create fishmeal and fish-oil products, while the remaining 20% is used for harvesting their roe.

The female species of the capelin fish start to ovulate when they reach 2 – 4 years of age and continue to do the same for the duration of their lifespan.

Fish farmers wait until the female capelin fish are full of eggs and then harvest them prior to the time when they spawn.

Masago is commonly used as one of the ingredients of sushi and it has a light yellow color, although chefs dye it with colors like orange, red, or green in order to add visual aesthetics to their sushi dishes.

It has a mild flavor and sometimes sushi chefs mix it with ingredients for condiments such as wasabi, squid ink, or ginger.

Ikura (salmon roe)

Blob-looking large red-orange spheres that are larger than most fish and seafood roes.

Since salmon eggs are also used as fish bait, fishing and outdoor-loving buffs might be surprised to find salmon roe served in their food.

Ikura is actually a borrowed Russian word “икра,” which means “soft-shelled eggs” used only in the context to describe caviar.

Ikura is commonly used by sushi chefs to garnish sushi rolls.

It is used not only to add aesthetic appeal to the sushi dish but also to add extra flavors in order to satiate the customer’s appetite.

The common misconception about caviar is that it’s an expensive or fancy food; however, it’s actually a common food in Japan.

Salmon roe is more affordable compared to other types of caviar, because they’re more accessible.

You can actually find ikura in just about every supermarket and convenience store in Japan.

Doctors and health professionals actually recommend that you consume ikura moderately as it is rich in Omega-3 fatty acids.

If you’d like to read more about sushi rolls and their calories, you should read this article I’ve written on the different types of rolls and their calorie counts.

Tarako (pollock roe)

Tarako is plain, salted sacks of pollock or cod roe.

These tiny egg sacks are known for their incredibly tender texture, mild – neutral flavor, and light pink color.

You can also eat them plain or mixed with other recipes such as sushi and sashimi.

They are also used to make spaghetti sauce, except they are cooked if they are mixed into it in order to add flavor to the sauce.

It is called mentaiko (a common ingredient in traditional Japanese cuisine) when it is marinated with salt and chili peppers.

Sujiko (salmon roe that is still within its egg sack)

Sujiko is different from ikura, because the fish eggs are still inside the egg sack when it is consumed, while ikura is served as individual eggs.

When sujiko is cured it is almost difficult to tell the difference between it and ikura as they have similar taste and texture.

Sujiko Kasuzuke (sujiko mixed with sake Kazu) can be eaten plain without any added ingredients and it tastes even better with wine or sake.

Sujiko is usually served with rice in onigiri dishes (a favorite rice cake in Japan).

I’ve written this post on some of the best sake brands you can use for cooking so be sure to check that out as well.

Kazunoko (herring eggs)

During Osechi Ryori, which is the Japanese New Year, the Kazunoko (herring fish eggs) is a popular dish among locals and they consider this dish as something that will bring them good fortune.

It’s herring roe that’s marinated in dashi soy sauce seasoning.

The tiny herring roe has a lovely golden color and they are crunchy to the bite.

The Kazunoko has the combined flavor of umami (from the dashi), salt and soy sauce.

Paddlefish Caviar

An inexpensive alternative to the sturgeon caviar, Paddlefish Caviar is also called “spoonbill” caviar as the fish has a bill similar to that of the duck.

The paddlefish caviar is harvested from the freshwater sturgeon in the United States and is considered as good caviar to start when you’re a beginner to the sushi and caviar avenue.

Whitefish Caviar

Whitefish is only found in the Great Lakes of North America, its eggs have a golden hue, are very small, have no trace of fish flavor and are mild to the taste.

The fish eggs are also crunchy to the bite and are quite popular in Scandinavia, the people call it Sirkom in the Dano-Norwegian language.

The whitefish caviar is a versatile food raw material that goes well with a multitude of recipes – including soups and sauces.

Bowfin Caviar

The bowfin caviar also is known as Cajun Caviar and with its local Cajun name “Choupique,” has been popular in Louisiana since the 15th century AD.

The bowfin is a freshwater fish native to North America and although it doesn’t belong to the sturgeon species, it is known to have high quality yet affordable roe.

Bowfin caviar is a great garnish for sushi and sashimi recipes, but they’re also used to make baked goods and the fish roe turns red when cooked.

Black Lumpfish Caviar

An inexpensive yet very delicious entry-level caviar that’s great for gourmet meal recipes – the black lumpfish caviar would be the best choice when you’ve just started out in the caviar world.

Enjoy eating it from the jar, on canapes or sushi.

It has a strong salty fish flavor, crunchy to the bite and the black lumpfish roe is smaller than regular fish roe.

Trout Caviar

Although there are wild European Rainbow Trout some are bred in aqua farms and those are raised strictly following all Animal Welfare laws.

Its eggs give off a bright orange color and it has a smokey sweet flavor.

The trout caviar is great for the canapé, fish, shellfish, and eggs. This is one of the most versatile caviar and it works well with almost any dish.

Tuna Bottarga

Bottarga is a delicacy of salted, cured fish roe that comes from bluefin tuna or the grey mullet dried egg sack.

The bottarga has different names across different countries where it is produced and is prepared in different ways as well.

For instance, the Japanese call it “karasumi” (softer than the Mediterranean version) and the Koreans call their bottarga, “eoran” (made from freshwater drum or mullet);.

However, the Mediterranean version of bottarga is known to be the best of all the types of bottarga dried and cured fish roe.

Uni (sea urchins roe)

Uni is what the Japanese call the edible part of the sea urchin roe.

Although often called roe (eggs), uni is actually the animal’s reproductive organ, which produces the eggs or milt.

The color of uni ranges from rich gold to light yellow, and the milt produces a creamy liquid that may put off some people and may make others enjoy it.

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However, the demand for this type of roe is so high that it cost $110 – 150 per tray in US fish markets alone.

Check out my post on all of the different types of American and Japanese sushi for more on the differences between the two.

Joost Nusselder, the founder of Bite My Bun is a content marketer, dad and loves trying out new food with Japanese food at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.