Do lightning strikes on the ocean kill fish?

Chris Smith put John's question to marine biologist Danielle Green...

Danielle - When lightening strikes the sea it spreads out horizontally rather than vertically so it would spread out along the surface. And because most fish and marine organisms tend to live at deeper depths they’re likely to avoid being struck by lightning but it doesn’t mean that they can’t be. There have been cases where people have observed lightning strikes and then seen dead fish floating on the surface. So I think they can be but it’s not something that is a huge problem because it’s not like it’s going to radiate across the whole earth.

Chris S - Because it’s spreading out and, as it spreads, it’s going to weaken quite considerably isn’t it? So the electric field to which the fish is going to be exposed is going to diminish really quite rapidly.

Danielle - Yeah. And in terms of marine mammals as well, there’s been some observations, sort of fisherman’s tales - I’m not exactly sure if it’s true or not - witnessing a whale being struck by lightning and things like that. If a human gets struck by lightning they don’t always die - I think it's 20 percent or something like that. It’s not a good thing. You wouldn’t go out of your way to get it but they’re not always going to die from it anyway. So I think it is something that’s possible but it’s not a huge problem because they’re usually deeper.

Chris S - Tim?

Tim - One of the first things I ever did for the Naked Scientists was piece about a person who’d been struck by lightning and wanted to know about it. The thing I most remember about this is we interviewed someone in the US who was all about lightning safety and he came up with this great phrase that I will remember till the day I die which is “when thunder roars, stay indoors.”

Chris S - Good quote. Farmers, Chris say they sometimes find animals that have died in fields. They sometimes argue that lightning hits the ground or something and then travels across the ground and if you put a long animal like a horse or a cow, it could go up the front legs, along the body killing the animal enroute, and then out the back legs. Do you think that’s true?

Chris B - Yeah. I definitely think it’s possible. Imagine the setting… you’ve got a nice open field with livestock - it seems like a good recipe for lightning strikes. I often wonder are giraffes particularly sensitive to this problem? They tend to hang out in open spaces.

Chris S - But they’ve also got an inbuilt lightning conducter, haven’t they?

Chris B - Exactly.

Chris S - And is that the case because you get some pretty vicious thunderstorms over the areas of Africa where these animals live

Chris B - Again, you hear lots of stories of people saying they’ve witnessed lightning strikes in giraffes. Yeah, I don’t know.