Heidel is here with Ted talks daily. Ted is on vacation this week, so here's something a little different. Ted Short's a podcast that shares a quick new idea each day. Did you know that baby fish and other ocean animals like clams, oysters and crabs use sound to select their best habitats? It's all about listening to the soundscapes of the ocean here, all about it in this episode. And if you like what you hear. Check out Ted Schwartz wherever you're listening to this.

The reef is alive with noise and that noise has patterns, and we've explored this by combining recordings with underwater surveys and with our underwater surveys, we realize that we can hear whether there are coral there.

We can hear which species live there. We realize that the fish at sea are doing much. What we would do if we were moving to a new city, we'd perhaps get on the Internet and do some research into different suburbs that we might want to live in. We think fish can do the same thing by listening to their environment and choosing where they want to live. We now know that all sound different. They have signature sound baby fish can select the best habitat for their kind by using sound.

And amazingly, it turns out so many other animals and coral reefs, crabs, lobsters, clams, oysters, even corals themselves. Now, I'm going to take you to a few places that we've worked, this is Balochistan, which is a marine protected area in the Philippines. You can see it's full of life, it's highly protected. There's no fishing.

And as a result, when we listen to it, it's a wonderful soundscape. You can hear the fish communicating. You can hear the snapping shrimp.

Now, sadly, if we go three days around the corner to Belang Berlanga and we find a more typical Filipino reef, this is a reef that's been heavily overfished. So there are no herbivores to graze away at the algae which now smothers the reef. You can even see craters from dynamite fishing.

And when we listen to it. You can just about hear it, so a tiny fish would have to pretty much swim into this reef before it found that the next generation are not coming home.

We are changing the soundtrack of the ocean through overfishing and poor environmental protection.

Let's go somewhere better. Let's go to the Great Barrier Reef. This is from marine biologists, the benchmark.

This is where we go to see what coral reefs once were like, what coral reefs can be like with really effective management, highly protected marine reserves, long distances away from cities, from pollution, and as a result, beautiful, bustling underwater cities full of life.

You can hear the Great Barrier Reef. It's a wonderful thing. And we've studied this for 15 years to make reference to the reefs around the world. At least we have until three years ago when tragedy struck with painful predictability, we saw the water temperatures starting to rise. Oceanographic conditions meant the water was staying in one location and for three weeks, the Great Barrier Reef cooked. We saw the reef in front of our eyes dying, and when we go back to the Great Barrier Reef now, the snapping shrimp have gone.

The complexity, the diversity of the sound is missing, it's become an acoustic desert, and so we realized with climate change we are changing the soundtrack of the ocean. Now, these, in some ways, a gradual change is overfishing, poor quality, poor management, climate change.

But we also realize when we take our recording's on every day to day basis, we change the soundtrack of the ocean by driving motorboats around millions of motor boats every day, drive around coral reef environments with engines that rattle with propellers, that capitate creating bubbles which screech in the water as they burst. And we've realized that their sound causes stress to all of the animals that experience it. And with stress comes poor decisions. The fish are no longer able to respond to predators, to be able to find food, to be able to court, to be able to successfully reproduce this motorboat.

Noise is a form of noise pollution that makes us realize we are changing the soundtrack of the ocean. Now, if this was the end of the talk, it would be a sorry tale, but as a scientist, I asked myself, what is my role? What is my why am I trying to do? The science that I am doing is my duty simply to monitor, to measure, to assess how the world is changing and to report that, well, can we take that knowledge and can we actually turn it into practical solutions?

So here's the spiny Christmas. Wonderful fish lives on the Great Barrier Reef in monogamous pairs, a male and female living together.

They lay their eggs in the reef and their eggs hatch. And unusually, they bring their young through those first few weeks on the reef. They protect them. And you can see their baby fish out here, the larvae of the spiny chromosome. Now, if we monitor how well they do need boating channels, we realize that that motorboat noise means that the adults don't feed as well. They don't defend the larvae against predators in the same way. So is that a real tragic story of how with noise pollution, we're affecting reproduction?

Well, could it be that actually, if we turn it on its head, we realize our comparison is what happens if the boats aren't there? Could we be talking here about a story of an acoustic protection? If we go to the Great Barrier Reef and we play those sad recordings of the current state of the Great Barrier Reef, the fish no longer arrive in the numbers that we would hope for.

If we play the recordings of the Great Barrier Reef, as it used to be, the fish still come. So here are we talking about a story of the loss of a sensory cue that's essential to close the loop of the life cycle, or could this be a story about the potential value of acoustic enrichment? This is something that my group now are actively pursuing around the world. And we're hugely excited that there are tools with acoustics that we're realizing might be part of the solution.

So we realize it's our gift to change the soundtrack of the ocean in this generation, but to change it for the better, not the worse. With technology, we can improve the sound outputs of boat engines. Modern engines are far quieter. With environmental protection, we can keep boats away from breeding grounds, from nursery grounds.

We can give quiet nights to allow the fish to come in and settle. And with acoustic enrichment, we can potentially accelerate the recovery of habitats that have been worst hit. PR ex.