Why don't lightning strikes in the sea kill the fish?

Although lightning strikes do so mostly on land, a valid question is why it does not kill fish in the sea when it falls there. The explanation lies in the behaviour of electricity on the first levels of the ocean.

Lightning falling into the sea
Lightning falling into the sea off the coast of Spain.

A person who is swimming on the sea in the middle of a thunderstorm is a perfect target for lightning that can fall to the surface. Now, the question is, why then don't the fish suffer damage when a storm projects lightning on the water? First, you have to review the statistics to confirm that the rays that fall on the sea are a minority.

The dispersion of electricity in the sea is related to the salinity of the water that helps the dispersion to a wider area. But the lightning does not manage to penetrate very deeply.

Although the seas cover three-quarters of the planet, most of the rays fall on areas of land. So the probability of lightning falling on you while you bathe in the sea is low. But the cast that probability is low doesn't mean it can't happen. So it's better to avoid the situation. The truth is that it is even rarer for a fish to die from the impact of lightning.

The explanation is related to how electricity is distributed by the water that receives it. Although sea salt helps its dispersion in the water, it does not manage to penetrate much in depth, while it does so mostly on the surface. And for this reason, only those who swim near the surface will be able to receive any damage. And there the greatest candidate is the swimmer of our example, because most fish swim at a depth that gives them security.

The best advice is to avoid the situation

That is why when there is electrical activity it is best to leave the bathroom. And keep in mind that on the beach, the probability of receiving lightning discharge increases exponentially with respect to the sea. The best advice is that when we hear thunder, we must understand that the storm is close enough to project lightning. So, when there is electrical activity and we are on the beach, the safest thing is to abandon it, the same as if we are swimming in the sea.

Knowing then this behaviour of the electricity of a lightning bolt when reaching the sea, we understand how the vast majority of animals that live in the sea are rarely affected by lightning. A study carried out by the Bialystok University of Technology, in Poland, concluded that the distance that the electric current is able to travel depends on the salinity of the water.

There it can be concluded that open sea water is where electricity is most easily distributed, and to a lesser extent in the coastal area. Having minimum amounts of salt, the distribution is much lower in the rivers, and in the swimming pools. In some cases, the rays have reached the bathroom shower after traveling through the pipes of the supply networks.

The security zone

The aforementioned study also gives data on safety distances. There it is indicated that the safe distance for a person swimming in the sea with respect to the impact of lightning is about 30 meters. Now, taking into account that this discharge expands in all directions, the life-threatening area covers about 2800 square meters. Although it may seem ironic, the fish are saved by the water shield that surrounds them.

To understand the power of this phenomenon, the National Atmospheric and Oceans Administration of the United States (NOAA), has provided details. A typical lightning can discharge up to 300 million volts and 30,000 amps, enough to kill any human being. Anyway, no one would think of doing statistical calculations. It is better to get away as quickly as possible.

If it is true that the largest number of lightning strikes on beaches occur in summer due to the increase in the concentration of people. And in fact it is on weekends when that probability skyrockets. Few people effectively leave the beach despite the great risk of being there with a developing storm.