Things to watch out for when preparing mackerel sashimi and its fishy smell

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There are many people who enjoy mackerel fishing, but not many people eat mackerel sashimi. The reason for this may be that they don’t know how to prepare sashimi, but I think it’s more because they’re worried about histamine food poisoning, which mainly occurs from anisakis or blue-backed fish.

However, some people are reluctant to take home mackerel they caught while fishing and cook it because of the strong fishy smell. Recently, a rumor has been spreading on the Internet that removing the skin of the mackerel will eliminate the fishy smell. However, not only is it difficult to peel the skin of the mackerel, but it is not entirely true that removing the skin will eliminate the fishy smell.

Mackerel skin is often removed, especially when preparing sashimi. This is often done to remove the scales (which many people don’t know about) found on mackerel, or to accommodate those who dislike the texture of the skin. However, mackerel skin is also used to prepare special dishes.

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People who fish catch fish and cut their nerves or drain their blood, but housewives usually catch fish in large quantities using nets when cooking at home, so they cannot drain the blood individually, and the fish die because they cannot breathe.

Especially when a quick-tempered fish like mackerel suffocates to death, ATP (adenosine triphosphate) is rapidly depleted, leading to immediate rigor mortis. This  rapid progression of rigor mortis can cause the skin to lose its luster, and the fish’s body temperature can rise, causing discoloration.

Also, since fish blood contains various enzymes, if these remain in the body, they can break down or change proteins. In particular, in blue-backed fish such as mackerel, the risk of causing histamine food poisoning increases as the bacteria called Morganella morganii acts as an enzyme on histidine, one of the 20 or so amino acids that make up the protein contained in the food, converting histidine into  histamine .

In addition, red-fleshed fish with sarcomeres, which are dark red muscles distributed along the sides of the fish’s body, are mostly migratory fish that have to swim continuously, and as their freshness decreases, their color turns black.

 

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Therefore, when purchasing fish fillets, it is best to choose ones with a clearer color of blood. And  the biggest cause of the fishy smell in mackerel is that the blood remains in the blood of mackerel that was caught with a net and not drained. When cooking at home, the fishy smell of the small bones in the blood area is strong, so removing them before cooking is actually more effective in removing the fishy smell.

Therefore,  it would be good to remember that the main cause of the fishy smell in red-fleshed fish such as mackerel is that the blood that has gathered in the blood-clotting area is not properly removed .

Not only that, the fish skin is rich in protein including collagen, and it is also rich in vitamins A and B₂. In particular, 10% of the vitamin B₂ contained in the whole fish is distributed in the skin. DHA and EPA, which come to mind when thinking of blue fish, are also abundant on the back of the skin, so unless you avoid it because it gives a bad texture, it is not a very desirable thing to remove it when cooking, and that can be said to be the same as peeling and eating an apple.

So, finally, let’s look at what you need to be careful about when preparing mackerel sashimi and finish.

When cutting mackerel sashimi, it is usually done by cutting it into three parts as shown below. However, if you do not remove the small bones in the belly area, the texture will not be good and it may even have a fishy taste, so it is better to cut it like the second picture.

 

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Lastly, when you have time to prepare sashimi at home, it is a good idea to remove all the bones in the blood-stained meat mentioned above. However, since it is inconvenient to remove them one by one using tongs, it is better to cut off the boney part and then prepare the sashimi.

 

If you let go of a fish that has swallowed a fishhook, will it survive?

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When fishing, it’s common for fish to swallow the hook so deeply that it’s difficult to remove. In such cases, anglers generally accept the idea that simply cutting the leader and releasing the fish will save them. However, the National Fisheries Research Center of Japan recently published experimental results confirming that simply cutting the leader and releasing the fish is the right thing to do.

The experimental method announced by the Aquaculture Research Institute of the Fisheries Research Center of Japan involved cutting the necks of trout (Japanese salmon) caught by fishing and releasing them after they had swallowed a hook, attaching tags to them.

 

The results of the experiment showed that the needles remaining in the body of the maggot corrode, break off, and are excreted.

Additionally, it was found that 72 of the 77 released fish, or 93.5%, survived, and 53 of them, or 68.8%, were caught again by fishing.

When releasing a caught fish, it is best to release it in a healthy state if possible, but if the fish has swallowed a needle, it is better to cut the leash short and release it rather than forcibly removing the needle.

 

Until now, it was unclear how to properly dispose of the animal, but I hope that in the future, when it is difficult to remove the needle, many people will realize that they can survive by simply cutting the leash and releasing it.

I would also like to point out that catch-and-release, which is practiced with good intentions, can take the lives of fish, contrary to one’s intentions.

As I discussed in the article “Catch and Release Practice Begins with the Selection of Hooks” a long time ago, in countries like the United States where fishing is a sport, even the hooks used to increase the survival rate of fish are regulated in detail, even when the fish are released. It is true that research support from the government and companies plays a big role in making such regulations possible.

However, in contrast, in our country, there is a government move to impose a surcharge on anglers based on an absurd research report that the average catch of anglers is 6.5 kg. Therefore, we cannot help but criticize the convenient and desk-bound administration that sticks to a complacent policy of one-sided regulation.

As mentioned above, the United States has detailed regulations on even the hooks used for fishing, and numerous research reports provide the basis for this. I think that the research results announced by the University of California in 2018 are something that our anglers should think about and put into practice at least once, so I will summarize them.

It is something that can often be seen at fishing spots, but when fish are pulled out to release their catch, they often injure their mouths and sometimes even damage their organs.

If you are not used to removing the hook and you think it might cause damage to the fish’s mouth or body, rather than forcing it out, cut the line and release it to increase the chances of survival.

Researchers at the University of California caught 10 shiner perch with nets and 10 with hooks near Canada’s Bamfield Marine Sciences Centre, and then used high-speed cameras to observe how the feeding behavior of the hook-caught fish was affected by injuries around the mouth.

 

As a result, it was discovered that fish with injuries around their mouths due to fishing hooks ate less quickly, and the way fish with injuries around their mouths inhale food is said to be similar to how we drink beverages through a straw with a hole in it.

The researchers say more detailed research is needed to determine how the decline in the fish’s ability to forage affects their long-term survival. Information about the research team can be found on their website (Higham Lab) .