From Porpoise Detectors to ‘Hawkeyes’, How Technology Empowers Ecology


On a warm winter afternoon as I unpacked my equipment onto a small wooden boat, one of my curious assistants approached me asking what was the red torch that I was holding. ”It’s not a torch,” I said hastily, checking if my survey sheet was in place. “It is a depth meter… umm… Depth dekhar jonno… (to look at the depth).”

Perhaps overwhelmed by my sense of urgency he moved back and let me continue my work. Soon, I jumped onto the boat, and was on my first survey of the River Ganga, at Farakka in West Bengal. Farakka, a small town in central Bengal, sits besides NH34, bustling with heavy movement of traffic and people all day long. It is perhaps the last place a layman would imagine a wildlife researcher to be in. Yet there I was, on a motored wooden boat in the middle of the vast Ganga, constantly dipping my depth meter in the water, recording its reading and looking for Ganges river dolphins at the same time.

‘What are you writing?’ asked the curious guy again as our boat – barely big enough for five people – rocked on crashing waves.

“Depth. Goirahi.” I told him.

“Hmm… goirahi ki kore deikhen?” he asked and immediately I had realised the subtleties of speaking a non-native language. He wanted to know how I was ‘looking’ at the depth.

I slowly explained to him that it is not light that the device uses, but sound. Sound – too high in frequency for us to hear – is emitted by one end of the depth meter and its reflection from the bottom of the river is received by an acoustic sensor on the same end. Since the speed of sound in water is known, the time elapsed between emitting this sound and sensing its reflection is translated into the distance travelled or depth – goirahi.

hawkeye imran samad depth sensor

A Hawkeye handheld depth meter used to measure the water level
Photo Credit: Imran Samad

He looked confused by the details, but refrained from asking any following questions.

As a student of curiosity, I love its other disciples. Therefore, on our journey ahead, I took to explaining him something a little simpler – a handheld GPS device. A device fitting in my palm, housing a dull coloured 2.2-inch TFT screen alongside a tiny joystick to navigate its menu.

It is a fairly common device used by all kinds of people all over the world to record their positions, navigate landscapes and so much more. It works just like the GPS on a smartphone used by applications like Google Maps, but is designed to work in harsher and more rugged environments, also offering plenty of battery backup. After I had explained it to my assistant, he would often look at the odometer at display on it, and scream atop the engine noise about the distance that we had travelled so far. His friends at the rear end of the boat were equally happy to receive the news. Perhaps it was a new way of looking at the river — that they had grown up around — that filled them with fascination.

At the survey’s end, as we stood on the dock discussing future plans, my assistants were calm and happy. They by now could better visualise the river in a third dimension, quite accurately.

A few days after some consecutive surveys, I had become good friends with my assistants. I told them to be ready at the Ghaat on a cold December morning; I was bringing the CPOD with me.
Surveys are important to know where dolphins are at a point in time, but it is impossible to know how they move all throughout the day. Do they stay in close proximity to one spot? Or do they move a lot? To know this, one would have to sit on a still boat for the whole day, and record dolphins as they surface to breathe. This of course would be a tiring task! But this is exactly what the CPOD does, with minimal complications and biases.

CPOD VLIZ dolphin detector

A CPOD deployed underwater
Photo Credit: VLIZ

A Cetacean – POrpoise Detector records the parameters of the vocal signal of a dolphin.
Just as we speak in sentences made up of words, river dolphins communicate in long trains made up of clicks, which have certain properties like frequency, SPL (loudness) and so on. A CPOD records these parameters along with time. Therefore, in effect it becomes like a watchman who is always on alert for dolphins. Since it is a passive logger, it does not affect the animals.

Just like this, much of what researchers do is simple conceptually. It is the translation of their concepts into reality that is complex. How exactly do you employ a watchman underwater? In fact, the quality of research one does is contingent on the quality of this translation, the equipment employed and the methods used. Growing technology and steady access to it is gradually transforming the way we look at our surroundings. 

In fact, there are many interesting devices that researchers use to observe and understand the world. One such device that excited my assistants more than ever was the Chart-plotter. It works on the same principle as the depth meter and is used to ‘see’ underwater, just like how a paediatrician ‘sees’ and assesses a foetus inside a womb. With this, river qualities like its shape, presence of fish and so on can be better understood.

Improving technologies are heavily empowering research, yet one must always remember that any gadget used is only as good as its user. With proper logic and motivation, you can find new ways to look at the same old things. So always stay curious; your observations may someday change the world.

Imran Samad is an engineer turned wildlife biologist who is fascinated by the nature of nature. He is currently enrolled in the M.Sc. in Wildlife Biology and Conservation at NCBS, Bangalore, where he is studying cetaceans. He also loves to write poetry on his blog.

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