Earthworms don’t live in water, so why do fish like to eat them?

Author: Su Chengyu

The article comes from the Science Academy official account (ID: kexuedayuan)

——

Earthworms, a creature that lives underground all year round and only risks its life to come to the surface during heavy rains, are a common bait used by humans for fishing.

One lives in water, the other lives underground. Fish and earthworms seem to have nothing in common. So, do fish really like to eat earthworms? Why?

Earthworms (Photo source: Farmers weekly)

The love between earthworm and fish, is it just an accident?

The reason why earthworms like to come to the ground on rainy days is that they breathe through their skin. The microvessels on the skin of earthworms can breathe directly through gas exchange, so they should always be kept moist. In order to keep the skin moist, the dorsal pores of earthworms secrete mucus, so touching earthworms will feel sticky.

After the rain, the gaps in the soil are filled with water, and the air is squeezed out. Without air, the earthworms can't breathe underground and will suffocate to death, so they run to the surface. Although there are great risks in doing so, such as being stepped on to death by you, but in order to survive, the earthworms have to leave the water-soaked underground.

So earthworms can't actually survive underwater. If you put an earthworm in water, it will just drown. Except when strong winds and heavy rains may wash some earthworms into a fish pond, or when fishermen use earthworms as bait, fish cannot see earthworms under natural conditions.

The strips move again, eat it!

Since fish cannot see earthworms under normal circumstances, why do many people use earthworms as bait?

Earthworm bait (Image source: newscientist)

A simple explanation is that while most fish will never encounter earthworms in their lifetime, they will encounter things that look like earthworms, such as insect larvae or leeches. Fish are rarely picky eaters, and these long creatures are their food. Because earthworms look like the food they usually eat, fish also like to eat earthworms.

In addition, fish also like to eat moving food. Because insects struggle, they are particularly interested in insects that fall into the water. Earthworms, as bait, will also twist and struggle underwater due to suffocation and the pain of being pierced by hooks.

So, is it because fish like to eat worm-like and moving foods that humans use earthworms as bait?

As long as the shape is right, I will pick you?

The speculation still needs to be confirmed by experiments. In an experiment conducted by the Berkeley Fish Research Center, researchers prepared some perch that had never seen worm-like food since birth and put them in a special fish tank, and then hung some plastic fragments and worm-like plastics (hereinafter referred to as worm plastics) in the fish tank.

Worm-like plastic (Image source: some.yearib.xyz)

As a result, the bass had no interest in the plastic fragments, but reacted strongly to the plastic worms. Even if they couldn't eat them, the bass would frequently attack the worm-like plastics with their mouths. Interestingly, the researchers did not shake the plastic worms, which means that the plastic worms were stationary in the water, but the bass still liked to attack them. The data showed that the bass attacked the plastic worms about 10 times more than the plastic fragments.

As for why bass like these colorless, odorless, and motionless plastic worms, the researchers did not give an explanation, perhaps because the fish like these worm-like things in their genes.

Because the researchers discovered this secret, a new bait appeared in the fishing world in order to trick fish into taking the bait: plastic worm bait. In order to make it easier for fish to take the bait, people also add salt or other seasonings to the bait.

Plastic fishing bait (Image source: amzon.com)

This kind of bait can not only catch fish, but also can be recycled many times. As a fishing bait, it is indeed much more affordable than live earthworms.

Fish caught with plastic bait (Image source: union sprtsmens alicance)

The method of fishing with this plastic bait is called Lure fishing (Lure is the transliteration of the English word Lure), also known as bionic fish fishing, which is a popular fishing method in the European and American fishing circles. Generally speaking, Lure fishing is used to catch some big fish, such as the big bass mentioned above.

The plastic baits used in lure fishing are not only worm-shaped, but also small fish-shaped, or other underwater creatures-shaped. These shapes are determined according to the food that the fish you want to catch likes to eat.

A plastic fishing bait (Source: Wikipedia)

So, we concluded that the reason why fish like to eat earthworms is mainly because fish are interested in those strips, even if the thing is plastic, the movement is just a bonus. Do you remember?

References:

http://www.berkley-fishing.com/Berkley-ae-why-do-bass-eat-plastic-worms.html

https://en.wikipedia.org/wiki/Fishing_lure