Does Lightning Kill Marine Animals?

The 1st century CE Roman naturalist, Pliny the Elder, mentioned that in an event of a thunderstorm, it is most advisable to slip into a tent made of a sea calf's skin, as only this marine animal is never affected by lightning.

Lightning can be nature's most beautiful and most disastrous phenomenon, both at the same time. A single bolt of lightning reportedly carries up to one billion volts of electricity―more than enough to destroy whatever it hits. Moreover, it can also reach a temperature of about 31,000ºC.

The burning of numerous trees, vehicles, and even humans, when lightning strikes them is, therefore, not surprising at all. From elevated landforms to deep valleys and immense expanses of water, lightning occurs everywhere, and while from a distance it seems to be one of nature's greatest shows, one can only experience fear as he/she gets closer.

The question, however, is how frequently does lightning strike the sea. A study conducted in 2001 by NASA revealed that lightning does not strike the sea as much as it strikes the land. In fact, most oceans of the world receive less than two strikes per year. However, the regions near the coasts are more susceptible to lightning strikes.

Even though lightning does not seem to strike the oceans much, one needs to note that such is not always the case. There are certain regions in the oceans, which can be termed as 'lightning hotspots.' These areas seem to attract more lightning than the others, and hence, they are obviously affected more.

Saltwater is an excellent conductor of electricity. So, the moment lightning comes in contact with the water of the sea, the electric current that it carries, spreads horizontally across the surface of the ocean. According to NOAA's National Severe Storms Laboratory, saltwater, being a good conductor of electricity, holds lightning on the surface of the sea.

The current that lightning generates, therefore, rarely tends to penetrate it. So, it is the surface of the sea which is most vulnerable to lightning. Owing to this, all things that lay on or in its vicinity are most likely to suffer due to lightning.

Different life forms dwell at different levels of the ocean―some on the surface, some others near the seabed, etc. Owing to this, lightning tends to affect all of them differently; in fact, it does not affect some of them at all.

Considering the fact that lightning hardly penetrates the surface of the ocean, fish and other organisms that swim within the depths of the sea are very rarely affected, except if they are somewhere near a hotspot.

Otherwise, only the organisms swimming on the surface of the water are killed when they come in contact with the electricity, which lightning tends to generate. Therefore, even humans are prone to electrocution while swimming on the surface during a thunderstorm.

Martin A. Uman of the University of Florida's Camp Blanding International Center for Lightning Research and Testing has analyzed that whenever lightning strikes the sea, if it does happen to penetrate the surface of water, its effect goes on diminishing as it goes downwards. So, the danger zone for marine creatures is only about 10 to 20 feet.

But again, such instances are not common. So, the answer to whether lightning can actually kill fish and other marine life, is pretty simple―yes, it does, but not often.