The sight and smell of the red sea bream

I always emphasize in my writing that to enjoy fishing more, it’s important to understand the currents, learn how to judge the seabed topography based on changes in the sea, and learn the ecology and habits of the fish you want to catch, rather than just choosing the right gear.

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Among them, understanding the ecology and habits of fish is closely related to fishing. Today, we will learn about the sight and color vision of the black sea bream, as well as its sense of smell, so that we can understand how to catch the black sea bream.

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To do so, it is recommended that you first read the articles linked below to learn about the general ecology of fish.

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Now, let’s examine the sight and smell of the black sea bream. If, after reading this article, you understand what kind of tackle and bait (groundbait) you should use to target black sea bream, then I will consider it worthwhile.

The perspective of a sea bream

According to research conducted by scholars by collecting retinal cells from the black sea bream, the black sea bream’s visual acuity is known to be around 0.14.

So, can a visual acuity of 0.14 be used to identify a leash? For example, if a size 2 nylon leash is used, the line diameter would be 0.235mm, meaning a black sea bream would have to approach within 12cm to identify the leash. If a size 1 leash is used, the line diameter would be 0.165mm, meaning a leash would have to approach within 8cm to identify the leash.

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You might be wondering, what effect would a 4cm difference have? However, the thinner the leader, the less wary the fish are and the harder it is to detect, which has a big impact on the catch. In addition, if you use a colored leader, it can also have a negative effect on the catch. This  has already been confirmed in the article linked above titled “Do the thickness and color of the leader really affect the catch?”

Color vision of the red sea bream

Color vision refers to the “ability to distinguish and recognize colors,” and the fact that red sea bream can distinguish colors was discovered through genetic analysis.

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It is said that the red sea bream has five “opsin genes” as shown below, which allow it to detect light and dark, red, green, and ultraviolet light.

· Rh1 opsin, which distinguishes between light and dark

· LWS opsin that distinguishes red

· Rh2A opsin and Rh2B opsin that distinguish green

· SWS1 opsin, which detects ultraviolet light

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Scientists say that the fact that the red sea bream possesses two opsin genes that distinguish green indicates its ability to distinguish yellow, a color intermediate between green and red. Therefore, the fact that red sea bream respond to corn and that products containing a lot of yellow are marketed as bait to catch red sea bream seem plausible.

It is also said that the black color of the black sea bream is related to the black sea bream’s ability to detect ultraviolet rays. When the black sea bream detects ultraviolet rays, it produces melanin pigment and its skin turns black to protect itself from ultraviolet rays.

The sense of smell of the red sea bream

As for the sense of smell of the black sea bream, as we learned in “Red sea bream with an excellent sense of smell,” the black sea bream has 55 dorsal plates. However, the black sea bream has slightly more dorsal plates, around 55 to 60, so we can see that the black sea bream also has an excellent sense of smell. 

In particular, it is said that the sense of smell of the red sea bream can detect very small amounts of amino acids, and the four amino acids that the red sea bream is known to particularly like are alanine, arginine, glycine, and proline.

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Taking advantage of this habit of the red sea bream, commercially available powder for red sea bream contains various amino acids. Incidentally, red sea bream reportedly prefers monosodium glutamate, commonly known as MSG.