Why do fish have to have spines? Will the fish be pricked by the spines?

Fish is a common dish on the Chinese New Year table because it sounds like "年年有余" (meaning "abundance every year") or "富贵有余" (meaning "abundance of wealth"). Braised, steamed, grilled, or served in hot pot... there are so many ways to eat a fish that it's hard to list them all.

However, although fish is delicious, its bones are dangerous, especially the small bones hidden in the fish meat, which are difficult to remove, making people afraid to eat them. During the Chinese New Year, there are always cases of people suffering from fish bones stuck in the throat in the hospital, and in severe cases, they are life-threatening.

What is fish bone? Why does such a delicious fish have bones?

01

Why do some fish have more bones and some have fewer?

In addition to a spine, many of the fish we commonly eat have intramuscular spines .

The mainstream view is that these intermuscular spines play a role in fixation and assisting muscle movement.

Lower bony fish have more bones . For example, in the more primitive Cyprinidae in evolution, the main economic fish in China's Cyprinidae, such as black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idellus), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), etc., all have more intermuscular spines.

The dark black part is the intermuscular spine. Image source: Patterson C, Johnson G D. The intermuscular bones and ligaments of teleostean fishes[J]. Smithsonian Contribution to Zoology, 1995, 559:1-85.

However, scientists have found that as fish evolved, their intermuscular spines went from few to many, then back to few, and finally disappeared . To some extent, it can be said that "these fish with small spines are not very advanced."

02

Freshwater fish have more bones and saltwater fish have fewer bones?

When eating fish, many people will say: "Freshwater fish have more bones, while saltwater fish have fewer bones." But in fact, this is mainly because the common sea fish we see have fewer bones, while river fish have more bones.

Some freshwater fish have fewer bones, such as snakehead fish, sea bass, etc.

Sea bass. Copyrighted image, unauthorized reproduction

Saltwater fish have relatively fewer spines, probably because the pressure of survival in the sea is high, and they need to swim very fast to avoid pursuit and predation ; while in freshwater, the pressure of survival is low, and they do not need such strong muscles, so intermuscular spines and loose muscles are enough.

Advanced fish, such as tuna, have strong muscles and do not need intermuscular spines, so they can swim very fast, reaching 50 km/h, while freshwater fish can only swim at 20 km/h. This makes the meat of marine fish more firm and elastic.

03

Will fish bones prick the fish itself?

Generally speaking, no, fish bones are actually fish bones just like our human bones .

It’s just that fish “bones” are smaller and lighter than the bones of us land animals, and are less combined with calcium to form minerals, and the collagen in them is not as tough.

In addition to the spine and ribs, the small spines of some fish may mainly play a role in supporting connective tissue and guiding muscle force [1].

The movement of fish will not be that violent, and the fish bones are wrapped by connective tissue, so even if they are sharp, they generally will not hurt the fish itself.

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04

Which fish have fewer bones?

If you are not good at picking fish bones, you can take a look at the following fish with fewer bones:

Golden pomfret, sea bass, mandarin fish, grouper, tilapia, yellow croaker, flounder, rainbow trout, etc.

Nowadays, artificially raised non-toxic pufferfish are also individually packaged and can be taken home and cooked and eaten. It is very interesting.

Many people now eat monkfish , known as the "ugly fish of the deep sea". The meat is chewy when cooked and tastes a bit like chicken legs, so it is also called "sea chicken legs".

Monkfish. Copyrighted image, unauthorized reproduction

Here are some fish cooking tips for you:

1. Thaw slowly

It is not recommended to take frozen fish out of the refrigerator and leave it in room temperature to thaw, as this can easily breed bacteria and cause loss of nutrients.

It is recommended to put frozen food in a refrigerator at 0°C-5°C the night before to thaw slowly. This will help reduce juice loss and prevent bacteria from multiplying rapidly, thus ensuring food quality and hygiene relatively well.

2. To steam fish, boil water first, then put the fish in. If you put the fish in cold water, it will smell fishy.

The fishy smell mainly comes from the volatile molecules produced by the reaction of free fatty acid fragments with trimethylamine oxide.

Scientists have found that aromatic plants such as green tea, onions, laurel, sage, cloves, cinnamon, and ginger can effectively reduce the fishy smell.

3. Change the knife before cooking the fish

Fish is generally streamlined and thick in the middle. You can change the knife and cut it in the thick part, and make a slanting cut every 1-2 cm in the thickest part to facilitate even heating and consistent doneness.

4. Simmer the fish over low heat and don’t cook it for too long

Fish muscles have a layered structure, with layers stacked up to form a "W" shape, and have a low connective tissue content, so they cannot maintain their shape well, which makes the fish meat relatively fragile.

Moreover, when heated to 50℃-55℃, the collagen in the connective tissue of the fish will begin to decompose, causing the muscles of the fish to begin to separate into sections. If you cook it for too long, the fish will "fall apart".

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05

Fish meat isn’t just white!

After talking about fish bones, there is also some knowledge about fish meat~

Have you ever wondered why the fish we often eat on the table are basically white?

This is because fish live in water, and the density of water is higher than that of air. As long as fish store some oil and air that are lighter than water in their bodies, they can easily float in the water. Unlike us terrestrial animals, they are not affected by gravity. Therefore, fish do not need bulky skeletons and strong connective tissues . This makes the fish skeleton small and light, the connective tissue is weak, and the muscles are white and soft.

But not all fish are so thin. There are also some muscular guys, such as tuna, which look red because their meat is rich in myoglobin.

Tuna flesh is red. This image is copyrighted and cannot be reproduced without permission.

In fact, fish meat has many colors, red, orange, and even blue , because it contains different color-rendering ingredients. It’s just that these colorful fish don’t often appear on the table, so their presence seems a bit low.

After learning so much knowledge, will you enjoy eating fish during the Chinese New Year more? Share it with your relatives and friends during family gatherings, and you will definitely become the most handsome guy on the table~

However, I still want to remind you again: Be careful when eating fish. If a fish bone gets stuck in your throat accidentally, it is recommended to seek medical attention in time. Traditional remedies are really not advisable!

Author: Yuzi Food Science Master

Reviewer: Chen Shengjun, Associate Researcher, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences

References:

[1] Harold Mackey. Food and Cooking, Milk, Eggs, Meat, Fish[M]. Beijing Fine Arts Photography Publishing House, 2013.

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