This is TED Talks Daily. I'm your host, Elise Hugh. Here's something I never thought about before.

Fish sex. It turns out the way fish have sex is wild. But we humans are interrupting intimate mating in the deep sea, which affects the entire food chain.

In marine biologist Mara J. Hart's 2019 talk from TEDx Mile High,

not only will she crack you up and keep you engaged, learning about crazy, kinky courtship

of marine life, she challenges us to do things differently so we can stop wreaking havoc on the fish.

Right now, beneath a shimmering blue sea, millions of fish are having sex.

And the way they're doing it and strategies they're using

looks nothing like what we see on land.

Take parrotfish.

In this species, all fish are born female.

Then later in life, she can transition into a male.

But it's not just a spectacular wardrobe change.

Her body can reabsorb her ovaries

and grow testes in their place.

In just a few weeks,

she'll go from making eggs to producing sperm.

It's pretty impressive.

And in the ocean, it's also pretty common. In fact, I bet nearly

all of you have at some point had a seafood dish made up of an individual that started life as one

sex and transitioned to another. Oysters, grouper, shrimp, seeing some heads, nodding, yeah.

But not all fish that change sex start as females.

Those clownfish we know from finding Nemo, they're all born male.

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