During their long lives at sea, fishermen have discovered that whenever they light a lamp or light a fire on their boat at night, many fish swim towards the light, and some even jump out of the boat. water. In order to study this fish habit, people turned on electric lights on the surface of sea water for closer observation. Under the lights, people have discovered that different fish respond differently to the lights. Some small fish in the middle and upper layers move in their own postures. Small herring are gathered on the outskirts of the zooplankton, one after another, one layer after another, swimming clockwise around the light. Like a huge whirlwind, if the lights go out suddenly, the little herrings will tangle and rush when the lights come on, they will quickly gather together and start again.will have their orderly gyrations. There are no specific rules for fish. Sometimes they swim calmly under the light, sometimes they come up from the depths in groups, rise to the surface and suddenly disperse. Sometimes they form a wide band in the bright area, like a turbulent stream. Water moves counterclockwise. In areas with low light, some fierce carnivorous fish often appear. Their response to light is quick and short, like hairtail fish. They initially stay quietly at the edge of the light zone, and when they find a bright spot in front of them, they fish and move. the shrimps gather together, they pounce on them, rush through the bright area, devour the small fish and shrimps, then quickly retreat into the darkness once they are satisfied.
There are different explanations as to whyphototaxis of fish, and among them there are many hypotheses. At present, everyone knows that the phototaxis of marine fish is mainly affected by the following factors: firstly, the change of light intensity itself, secondly, the change of light color, and thirdly, developmental stage or physiological state. of the fish itself. As for the deeper reasons, they remain to be explored in more depth and detail. Research on fish phototaxis can help people improve fishing efficiency in fish production practices, so this topic is very attractive to fisheries scientists.