TEDxMileHigh 2019

Read The Script:

Right now, beneath a shimmering blue sea, millions of fish are having sex. And the way they do it looks nothing like what we see on land.

Consider parrotfish. Every individual in this species is born female and looks like this. Then, later in life, when she’s big enough and the conditions are right, she can transition into a male. But not just an external transformation. Her body reabsorbs her ovaries and grows testes in their place. In a few weeks, she goes from making eggs to producing sperm.  It’s a complete sex change. 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, eaten a seafood dish made up of sea creatures that started life as one sex and then transitioned to the other.  Oysters. Grouper.  Shrimp. I see some heads nodding.

But not all sex-changing fish start as females. Those clownfish we saw in Finding Nemo are all born male, and then some transition to female. So, …in real life, after Nemo’s mom died, Nemo’s dad Marlin would have transitioned into Marlene, and Nemo would have mated with his father-turned-mother… you can see why Pixar took some creative license with the plotline.

In the ocean, sex change can go both directions and, sometimes, even back and forth.  And that is just one of the many amazing strategies animals use to reproduce in the ocean.  And, trust me when I say, it’s one of the least bizarre.

Sex in the sea is really fascinating, AND it’s really important.

It matters– not just for Marine Biologists like me who are obsessed with understanding these salty affairs. It matters for all of us.

Today, we depend on wild fish to help feed over two billion people; we rely on millions of corals and oysters to build reefs to protect our shorelines from storms; and we need medicines found in marine animals to fight cancer and other diseases. And for many of us, we turn to the diversity and beauty of oceans for recreation, restoration, and cultural heritage.

The only way we can keep benefiting from this abundance is if the fish and shrimp and corals today make fish and shrimp and corals for tomorrow. To do that, they need to have lots and lots of sex.   

Until recently, we really didn’t know very much about how sex happens in the sea—it’s not easy to study— but thanks to new science and technology, we know a whole lot more than we did just a few years ago. These new discoveries reveal two things: first, sex in the sea is really funky. Second, our actions are wreaking havoc with the sex lives of everything from salmon to shrimp.

It is hard to believe. So, today, I’m going to share some details about how animals do it in the deep, how we’re disrupting these intimate acts, and what we can do to change that.

Remember those sex-changing fish?

Well, in many places, fishing rules set a minimum catch size. Fishers can’t catch tiny fish, which means baby fish can grow and reproduce before they are caught. That’s good. So fishers go after the bigger fish. But for sex-changing species, such as parrotfish, targeting the biggest fish means targeting all the males. That makes it hard for females to find a mate. Or it forces them to change sex sooner, at a smaller size. Both impacts result in fewer fish babies in the future.

To responsibly care for these species, we need to know whether they change sex, and when, and how.

Only then can we set up rules to support their mating strategy. For example, by setting maximum size limits in addition to minimum ones. The problem isn’t that we can’t think of sex-friendly solutions;  it’s knowing which solutions to apply -because even species we know well, surprise us when it comes to their sex lives.

Maine Lobster are a case in point.

They don’t look all that romantic. And certainly not kinky. But, they’re both.

During mating season, female lobsters want to mate with the biggest, baddest males; yet, these guys are really aggressive, threatening male or female lobsters that approach. Meanwhile, the best time for her to mate is right after she’s molted, which means she has no hard shell for protection. So, she’s got to approach a surly male right when she’s at her most vulnerable. What’s a girl to do?

Spray him in the face –repeatedly–with her urine.  Pee is a very powerful love potion in the sea.

Conveniently, lobsters’ bladders sit right above their brains, and they can shoot their pee forward through nozzles located under their eye stalks. The female approaches, and as the male charges out, she lets loose a stream of urine and then gets the hell out of there.

A few days of this daily dosing is all it takes for her scent to transform him from a brute to a gentle lover. by week’s end, he invites her into his den. After that, the sex is easy.

So, how are we impacting this kinky courtship?

Well, her urine carries a critical chemical signal that works because it can be passed through seawater and lobsters have smell receptors that can receive the message. Climate change is making oceans more acidic—the result of too much carbon dioxide entering the sea—which could scramble the message. It could also damage the smell receptors. Pollution from land can have similar impacts.  Just imagine the consequence for that female should her love potion fail… this is the kind of subtle yet significant impact we are having on the love lives of marine life.

And lobsters are a species we know well. They live nearshore in the shallows. Dive deeper, and sex looks even stranger.

The fanfin anglerfish, live in black waters three thousand feet down, and the males are born without the ability to feed. To survive, they have to find a female, fast.  Meanwhile, the female, who’s ten times bigger than the male, releases a strong pheromone to attract a mate. The tiny male smells his way to her through the darkness, and when he finds her he gives her a love bite.  And that’s when things get weird.

The bite triggers a chain reaction where his jawbone disintegrates, his face melts into her flesh, and his body begins to fuse with hers. Their circulatory systems entwine, and his internal organs begin to dissolve…except for his testes. Those mature just fine. He basically becomes a permanently attached, on-demand sperm factory for the female.

It’s efficient, but not the kind of mating you see on a farm, right? It’s so weird! But if we don’t know that these strategies exist, or how they work, then we don’t know what kinds of unintended impacts we might have.  Even in the deep.

Just three years ago, we discovered a new species of deep-sea Octopus that broods its eggs on sponges attached to rocks on the seafloor at nearly 2.5 miles down. These rocks contain rare earth minerals, and right now, enormous bulldozers are being built to mine the deep sea floor for those rocks. Those bulldozers would scrape up all sponges, and egg, too. 

Knowingly and, in many cases, unknowingly, we act in ways that prevent successful sex in the sea.

Let’s be honest, we all know that dating and mating are hard enough without someone constantly coming in and killing the mood, right?

So, while I hope that you’ll leave today with some fantastic bar trivia about fish sex, I also ask that you remember this:

We are all far more intimately connected with the oceans than we realize. And this level of intimacy demands a different kind of relationship with the ocean.  One that recognizes and respects the enormous diversity of life in the sea – and its limitations.  We can no longer view our oceans as something “out there”- because we depend on the sea every day for our own food security, our health and wellness, and every other breath that we take.

And, it’s a two-way relationship, so the oceans can only continue to provide for us, if we in turn, safeguard that fundamental force of life—successful sex in the sea.

Like any relationship, we’ve got to embrace some change in order for the partnership to work.

This doesn’t mean giving up all seafood. Many species reproduce like crazy, and with the right management, they can handle a bit of fishing pressure. So for your next seafood meal, select local and sustainably caught or farmed species that are low on the food chain. Oysters, clams, mussels, small fish like sardines, or mackerel.

We can also rethink what we use to wash our bodies, clean our homes, and care for our lawns—all those chemicals wash out to sea and disrupt the ocean’s natural chemistry.

Industry must take a precautionary approach – protecting sexual activity where we understand it and preventing actions that might harm these animals in situations where we just don’t know enough…like the deep sea. 

And, in the communities where we live, the places where we work, and in the country in which we vote, we must take bold action on climate change.  Never has it been more important, nor more possible, to fight for the solutions we know exist—but time is running out…for lobster seduction, coral sex parties, and so many other species that depend on the right temperature and chemistry for peak sexual performance.

The challenge may seem as big as the ocean, but nature is on our side.  Animals want to reproduce.  We’ve even discovered some female sharks and rays that can reproduce without any males at all! We’re talking real-life virgin birth. The technique won’t save a population over the long term—sex between males and females is needed for that genetic diversity—but, it can help buy a population time. 

The drive to reproduce is truly a force of nature, and ocean animals are doing their part.  Imagine, if we did ours, working with this force, rather than against it!  We can help set the mood, and then step back to allow today’s, tomorrow’s, and future generations of fish the freedom to do what they do best… get their spawn on.

Thank you.

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