Fish naturally live in water and breathe through gills. Is there any way to drown them?

Drowning a fish sounds like a joke, but it is very practical in reality.

Generally speaking, only creatures that can't breathe in water will be drowned, while fish themselves live in water and can breathe freely in it. How did you drown? Of course, not all aquatic creatures can breathe in water, and as far as fish are concerned, not all fish have the ability to breathe in water.

For example, a fierce African lungfish breathes with its lungs. But when we say drowning a fish, we don't mean drowning these fish that can't breathe in water. The fish we are talking about is the fish that can breathe in water with gills. How can a fish be drowned? In fact, most people don't know how fish breathe. If you like raising fish or watching fish, you must have seen such a situation. In hot summer, when the dissolved oxygen in the water is insufficient, the fish will swim to the surface with their mouths closed.

What is the fish doing with its mouth open and its mouth closed on the water? Breathing, of course.

But fish breathe in water with gills, so what's the use of swimming to the surface? In fact, fish can't get oxygen in water. Let's see how the fish's respiratory system works. The respiratory organs of fish are called gills, which are located on both sides of the fish pharynx. The gills of fish are composed of gills, each of which is supported by a gill arch, and the gills are composed of gills, which are protein filaments on the gills of fish.

This design greatly increases the surface area of the fish gills, allowing more oxygen to contact the fish gills, and the fish completes breathing in this process. The reason why fish gills have a huge surface area is that the dissolved oxygen in water can't be compared with that in air. Generally speaking, the oxygen content in air is about 20%, while the oxygen content in water is much lower.

There are many factors that affect dissolved oxygen in water. Generally speaking, at standard atmospheric pressure, the oxygen content of a liter of water is about 4 to 9 mg.

The dissolved oxygen in water is very low, and the surface area of fish gills is the guarantee for fish to breathe smoothly. In water, fish should always keep enough water through their gills in order to get enough oxygen. Due to the existence of gill cover, bony fish can keep enough water through gills by swallowing water.

However, the temperature and air pressure of water body will affect the dissolved oxygen in water. In hot summer, the water temperature rises, the air pressure decreases, and the dissolved oxygen in the water is greatly reduced. In order to let more oxygen pass through gills, fish will float to the surface to breathe. In fact, fish can get oxygen not only from the water, but also directly from the air, but there are conditions, and the condition is that fish must stay in the water.

The density of water can ensure that fish gills don't stick to each other. When a fish leaves the water, its gills will stick together, so the fish can't breathe and naturally suffocate.

So fish can get oxygen directly from the air, but they must stay in the water. To drown a fish, it is enough to reduce the dissolved oxygen in the water. Increasing the temperature or decreasing the air pressure will lead to the decrease of dissolved oxygen. Considering that mom often tells us that children like to raise fish? There are bacteria in the water. Do you want to boil it and drink it when it's cold? So I tried to raise fish with cold boiled water several times, and the fish soon died.

I wonder if anyone has had the same experience as me. This is because the oxygen content in the water is greatly reduced after boiling, and the fish can't get enough oxygen to survive no matter how hard they try. Compared with bony fish, cartilaginous fish are more likely to drown, and sharks are typical cartilaginous fish.

Sharks don't have gill covers, so they can't keep swallowing water to make it flow through their gills.

The only way for sharks to breathe smoothly is to keep swimming. Only by constantly swimming can sharks ensure that there is enough water passing through their gills to complete their normal breathing. So once the shark is entangled in the fishing net, it will soon die, unable to move, and can only be drowned by water. Shark fin is very popular, but shark meat is not, so many sharks are caught, cut off their fins and thrown back into the sea, and then slowly drowned in the water. Seeing this, you will feel that the shark that looks terrible at ordinary times is actually very pitiful.

Since sharks suffocate so easily, how can sharks be caught to watch their breeding? There is something called a water pump. After the shark is caught, people will quickly insert a water pump into the shark's mouth to let the water flow through the shark's gills to ensure the shark's normal breathing.