"I Counted the Vaquita by Sound"
Dr. Ana María García has spent 22 years studying the acoustic signatures of the vaquita porpoise, deploying underwater microphones across the Gulf of California to track the last remaining individuals. Her monitoring network is the only system that provides continuous data on the species' population trajectory.
People ask me if I love the vaquita. The honest answer is that I don't think about it in those terms. You don't spend 22 years listening to an animal out of love, exactly. You do it because the vaquita is the only thing in my professional life that has never let me stop caring. When you listen to it long enough, it becomes impossible to walk away.
Every species has its own sound. The ocean is not silent—it is full of clicks and whistles and groans, and each species has a click that is as distinctive as a fingerprint. The vaquita's click is very high frequency, much higher than most dolphins. It sounds almost electronic when you first hear it, like a staccato pulse on an old synthesizer. The way I describe it to people who have never heard it is: imagine someone tapping on a glass rod underwater, very fast, with increasing urgency. That is the vaquita's echolocation click, the sound it uses to navigate and find prey in the murky water of the Gulf.
In 2015, when we deployed our expanded monitoring network, we were hearing the vaquita constantly. Every station, in every direction, was picking up clicks. We could estimate how many individuals were in an area by the density of the clicks, by the overlap between different acoustic signatures. We thought we were close to understanding the species well enough to save it. We had 59 individuals. It was terrifying, but it also felt like we had something to work with.
By 2018, we were down to 19. I remember the exact moment I realized how bad it was. I was in my lab in Ensenada, reviewing data from our acoustic stations, and I noticed that one of our most reliable stations, in an area where vaquitas had been regularly detected for years, had gone silent. Not broken—the hydrophone was working fine. The vaquitas had simply stopped going there. I spent a week rechecking the equipment, the algorithms, the analysis. Then I realized the truth: the vaquitas were gone from that area. Not migrating. Gone.
That is how this species disappears. Not in a dramatic mass stranding, not in a catastrophic event. It just gets quieter. The clicks become less frequent. The silences between them grow longer. Until one day, you review the data and realize that the last click was recorded three months ago, and you cannot be sure if it was one animal or two, if it was healthy or sick, if it was the last one.
We now have four acoustic stations that still detect vaquita clicks with any regularity. In the past year, we have recorded 11 confirmed vaquita detections across all four stations combined. Eleven detections. That could be 11 individuals, or it could be the same individual detected 11 times, or any combination in between. The honest answer is that we do not know exactly how many vaquitas are left. The number we use—10—is our best estimate based on all available data. It might be 8. It might be 12. What I can tell you is that the acoustic signature of the vaquita is growing fainter across all stations, and that is not a good sign.
The proposed plan to capture the remaining vaquitas and place them in a protected sea pen is, I believe, our last chance. It is an extraordinary intervention, and I understand why people are hesitant. Every previous attempt to capture a vaquita ended in the animal's death. But every previous attempt was done under emergency conditions, with inadequate equipment and insufficient planning. What is being proposed now is different. It would be the most carefully planned wildlife capture in history, led by experts who have spent years preparing for it. The vaquita is too valuable to lose because we were too afraid to try something difficult.
I have a recording from 2019 of a female vaquita and what we believe was her calf. The calf's clicks are higher, faster, slightly chaotic—the sound of a young animal learning to echolocate. I play it sometimes when I am alone in the lab. It reminds me why I do this work. It reminds me that there is something worth saving in that click, something that has been making that sound in this particular corner of the ocean for millions of years, and that if we let it go silent, we will have failed at something fundamental.
The vaquita is counting on us. I wish I could say I was confident we would come through. But I can tell you this: the moment we stop listening is the moment the ocean goes silent.