The Pink Neighbors of the Pearl River

I. A Pink Face in Murky Water

My name is Ming, I am a Chinese white dolphin, that is what humans call us. But I am not white, I actually born in dark gray. As I grow, my skin turns lighter, some of us become speckled, some become pink. As I'm a adult now, I am pink with some grey speckled on my back. That pink color comes from blood vessels near the surface of our skin, helping us cool off in warm water. It is not a disease or a mutation. It is just how we are built.

You can find me in the western of Hong Kong water, near Lantau Island, around the Pearl River Delta. This is where the river meets the sea, where fresh water and salt water mix. The visibility is poor, the water is brown and cloudy from sediment. But I do not need to see far. I use sound, just like a sonar, to navigate, find fish and talk to my family.

We have lived here for a very long time. Long before the airport. Long before the container terminals. Long before humans decided that this estuary was a good place to build a city.

I have lived here my whole life. And for almost as long, I have had a best friend.

II. My Best Friend, Tai

This is Tai, he is a finless porpoise. We look similar, but you can tell us apart easily if you pay attention. I have a dorsal fin, the fin on my back that cuts through the water when I surface. He does not. His back is smooth, like a pebble show up on surface of the sea. That is why humans call him "finless."

He is smaller than me, rounder in the body, with a face that always looks like he is smiling. We met when we were both young, chasing the same school of fish near Sha Chau. Most dolphins stay with their own kind, porpoises do too. But Tai and I became friends, and we have stayed friends ever since.

We do not hunt together, we hunt in different ways. I am faster and more flexible, he is more patient, an ambush hunter. But we always see each other, as we share the same feeding grounds, the same sheltered bays, the same routes through the shallow water. When I surface for a breath, he is often nearby, surfacing a moment later. When he finds a good spot to rest, I will always be nearby.

We keep an eye on each other. Not because of strategy, just because of familiarity. He is the face I see most often in these waters except my families. Over the years, I have learned to recognize his smooth back and his quiet way of moving. I think he also recognizes my pink skin and my sound of clicks.

We are not the same species. But we share the same home. And lately, we share the same troubles

III. The Shrinking Neighborhood

Our home is being cut into pieces.

The problem is reclamation. Humans take the shallow waters near the shore, pump sand and rock into them, and turn sea into land, they have been doing this in Hong Kong for decades. The old Kai Tak airport was built on reclaimed land, and now the new Chek Lap Kok airport sits on a giant platform of fill. The projects takes a bite out of our habitat.

Dolphins do not need deep water. We prefer to live in shallow bays and estuaries where the fish are abundant and the waves are calm. Those are exactly the places humans want to fill in. Every time they reclaim a stretch of coastline, they remove our feeding grounds, nursery areas, and transition corridors. The remaining habitat gets smaller and more fragmented.

It is like having a neighborhood with roads that keep getting blocked off. You can still get from one place to another, but the detours are longer, and some parts become unreachable after it's filled.

We have learned to adapt. We avoid the loudest construction sites, we find fish elsewhere. But there is a limit. When you take away too much of the shallow water, there is nowhere left to go.

V. The Roar from Above and Below

Then there is the noise.

The airport at Chek Lap Kok sits right in the middle of our range. Hundreds to thosands of planes take off and land every day. The sound of jet engines rumbles through the air and transmit into the water. You might think sound does not travel well between air and sea, but you would be wrong. Low-frequency noise penetrates the surface easily, we heard it, and can even feel it in our bones.

And that is just the noise from above. The noise from below is even worse.

The waters around Hong Kong are some of the busiest in the world. Container ships, high-speed ferries, fishing boats, speedboats they all make noise when they travel though. Propellers churn, engines hum and sonar pings. All of these sounds travel for kilometers underwater.

We use sound to survive. Our clicks bounce off fish and rocks, creating a sonic image of the world around us, and our whistles carry messages to other dolphins. When the ocean gets noisy, we cannot hear each other to communicate, we cannot hear our prey, and we cannot hear danger approaching.

Some dolphins have been observed changing the frequency of their clicks to avoid overlapping with the noise of ships. Others just move away from the busiest areas, although there is not much quiet water left. The noisy zones keep expanding, and the quiet zones keep shrinking.

Tai feels it more than I do. Porpoises are more sensitive to noise than dolphins. Their hearing is tuned to higher frequencies, and the rumble of engines and propellers overlaps with the sounds they use to find food. Sometimes when the noise gets louder, I notice him surfacing more often, breathing harder, looking confused.

IV. The Long Journey to the Fishing Grounds

One of the biggest changes has been the way we move.

We used to travel freely between the waters west of Lantau, around the Soko Islands, and up into Deep Bay. That corridor is now interrupted by the heavy marine traffic. Construction barges block passages. The coastline has been reshaped by reclamation. We have to take longer routes, swim through louder channels, or simply stay put and make do with less.

I know a female in my pod who used to take her calf to a specific cove near the airport. At that cove, the water was calm and the fish were plentiful. The cove is still there, but the noise from the airport and the passing ships never stops. She stopped going there two years ago. She found a smaller, quieter spot further south, but the fishing is not as much as the old cove. Her calf is thinner than it should be.

We are resilient animals, we adapt, but adaptation has a cost. Less food means less energy for reproduction. More stress means weaker immune systems. Smaller habitat means more competition among dolphins for the same fish, and so does Tai.

VI. The Ways We Cope

Despite everything, we are still here. We have not given up, and neither have some of the humans.

Marine protected areas have been established. North Lantau Marine Park, Sha Chau and Lung Kwu Chau Marine Park and The Brothers Marine Park for example, restricts certain types of boat traffic and construction activities. It is not perfect, but it gives us a area of quieter water where we can rest and feed.

Speed limits have been introduced for vessels in some dolphin hotspots. Slower boats make less noise and are less likely to strike us. It makes a difference, especially for the mothers with young calves.

Monitoring and research have improved. Scientists track our movements with photo-identification, using the unique patterns of spots and notches on our dorsal fins to tell us apart. They know where we go, when we breed, how many of us are left. That data helps decide where to put new protected areas and how to manage ship traffic.

Mitigation measures for new developments now include acoustic monitoring and construction shutdowns if dolphins are spotted nearby. It is not always enforced, but the rules exist.

And we have learned a few things ourselves. We avoid the noisiest times of day, we feed at night when the boat traffic is less. We have found new foraging grounds in areas that humans have not yet developed. We are not thriving, but we are surviving.

VII. The Pink Neighbors

I do not know how many of us are left. The scientists say the number has dropped over the past twenty years. It is somewhere around two thousand individuals across the Pearl River Delta region. That sounds like a lot, but it is not. Not for a population that used to be much larger.

I still see other dolphins when I surface. We still travel together, hunt together, raise our young together, and I see Tai and his family. The water is still warm, fish are still here, though not as many as before. The airport still roars, the ships still rumble and the reclamation continues in some places.

But I have also noticed something else. More humans are paying attention, they watch us from speedboat, photograph us from the boat and shore, report our sightings to researchers. Some of them have never seen a pink dolphin before, and the look on their faces is wonder.

I do not know if that wonder will translate into action. I do not know if the protected areas will expand, if the noise will quiet down, if the reclamation will stop. What I know is that, we have survived typhoons, changes in the river's flow, and centuries of fishing pressure. We have learned to live alongside this city. We are still learning.

And as long as there is water to swim in and fish to eat, we will keep trying.