How Can Humans Protect Endangered Dolphins? | Changing Seas

The shallow, gin-clear waters of the Bahamas are a tropical paradise, a favorite spot for sport fishermen and scuba divers alike. These waters are also one of the few areas in the world where humans can regularly spend time with dolphins underwater. This is where we get the information about what the life of a wild dolphin is really about. The Wild Dolphin Project's research director and founder, Dr. Denise Hersey, has dedicated her career to immersing herself in the dolphin's world. In the wild, we deal with all sorts of challenges. Number one is weather. If we can't get to where they live, we can't see them. Number two is finding them because they might move 20-30 miles in a day, and it's a big ocean. And then spending regular time with individuals if you really want to get a sense of their society. That's also challenging. We're definitely at the mercy of the dolphins. They've got interesting lives without us. They don't really need to be around us or interact with us. So when they allow us in the water to spend a little time with them, it's always a great privilege. Through decades of patient observation and meticulous photo identification, Denise has documented the lives and behaviors of multiple generations of Atlantic Spotted Dolphins. The group is small. We're dealing with 100 animals, so you can get repeatability in different observations. I wanted to understand their society, how they communicate with each other individually and as a group. We tend to think of higher intelligence involving things like thinking about the future, planning, problem-solving, abstract concepts. Probably the one last thing on the list is language. Dolphins have shown that they can comprehend in an artificial language things like word order and understanding. That doesn't mean they have it in their own system. That still has to be shown if it exists. This is a story about scientific exploration, but it's also a story about friendship. Dolphins are like my kids, except I don't have to send them to college. It's cheaper that way. What can mankind learn from wild dolphins? Can we bridge the gap of understanding between us? A typical summer day on the research vessel Stinella begins early in the morning, with researchers taking turns searching for dolphins throughout the day. It's an expensive operation to spend four months at sea with 12 people. Finding the dolphins can be a challenge, but when they appear, the excitement is tangible. The researchers take photographs of the animals for identification purposes, and when the conditions are right, they enter the water to observe and film the dolphins' sounds and behavior. Denise started her research on the Little Bahama Bank in 1985, after having seen footage of the Atlantic spotted dolphins that live there. And I thought, wow, I could plant myself here for 20 years and try to observe these animals underwater. I had seen the primate work, and it seemed to take about 20 years to get a sense of development issues, to watch multiple generations, and I really wanted to get a sense of the society and the culture. For the first five years, we anchored the boat pretty much in an area where the dolphins went through, and we let them come investigate us. And we'd slip in the water, take identification shots with our cameras, try to get a sense of their dolphin etiquette. Then once they got comfortable with us, we started moving the boat around and following them into areas where they were feeding or fighting. So we started seeing a lot more behavior once we moved the boat, but we really wanted to invest in their trust of us. Denise's patience and non-invasive approach paid off. By interacting with the animals in their world and on their terms, the dolphins got comfortable enough around the researchers to display their natural behaviors. We take video in the water with sound to correlate sound and behavior. We track individuals with their spot patterns and typical nicks and cuts on their body. So every season, it's really important to try to get a picture of each individual. Spotted dolphins are actually nice to study, it turns out, because they get spots with age. Spotted dolphins are born without spots, and we call that coloration two-tone, because they're kind of gray on the top, white on the bottom. Then they get all sorts of dark spots on their belly, and we call them speckled. So now they're about four years old. Then at about age nine, they start getting white spots on the top, in addition to more black spots. We call that mottled, so that's a young adult phase. That's about the age the females get pregnant, so they can start having their first calf at about 10. The males develop later. At about 15, they'll become sexually mature. Now they're really black and white spotted. The spots coalesce. We call them fused. They reach physical maturity about 25. But we've had a few individuals that have lived into their 50s, so that's probably the top end of their lifespan. It's neat to see their whole history and their relationships over the decades. In the mid-1990s, the researchers also began collecting fecal samples to better understand how different animals are related, which is essential in understanding dolphin society. We can extract DNA, and that's the only way we can really get paternity. Sound and video recordings of the in-water encounters with the dolphins give researchers an opportunity to put their noises and behaviors into context. The dolphins make basically three types of sounds. For example, dolphins make frequency-modulated whistles. Sometimes they're unique to an individual, and we call those signature whistles. They're like names. But they make little chirps and other little kinds of up-sweeps and down-sweeps that probably mean different things to them, and they are not unique to individuals. Then clicks, those are basically their sonar. Burst pulses are clumps of clicks. Those are very social sounds, very unstudied, very broadband, so there's a lot of high-frequency information. Humans are unable to hear the high-frequency sounds, but modern underwater microphones, known as hydrophones, can record and display them as waveforms on a computer. Each evening on the boat, the science team logs footage from the day, identifying individual animals and documenting their behavior. One of the big challenges the scientists face when analyzing sound and behavior is figuring out which animal made what noise, since humans have difficulty telling the direction of where sound is coming from underwater. When you're recording dolphins, you're just getting the sounds from a group of dolphins behaving. You cannot always tell who's making a sound. But to get the real data about how dolphins are sending signals to each other, you need a localization device. This is where Dr. Matthias Hofmann-Kunt from the Acoustic Research Laboratory of the Tropical Marine Science Institute at the University of Singapore comes in. Together with colleagues, he developed a special high-frequency video and audio recorder called an Acoustic Source Position Overlay device. What we were trying to do is to build a device that allows us to have synchronized high-frequency audio recording with video and then overlay that so that afterwards we could tell this animal was vocalizing, this dolphin was just clicking or whistling, then this one responded, which is something that for behavioral studies would be very, very important. There's a lot of different behavioral situations where you might want to ask the question, does the mother make a whistle to get the calf back over to her, or does the calf make a whistle and the mother comes over? I mean, there's a thousand questions you could ask with that level of data. And up to now, that wasn't really possible. And so we came up with this device. And normally it sits in a pressurized housing, so you can take that snorkeling. We've got three underwater microphones here. They're high frequency. They're very, very sensitive. Then we have also a camera in here. Having three hydrophones instead of just one allows a specialized software to triangulate the source of the sound in post-processing. The camera and hydrophones are connected to a computer that can capture all the data and save it on an external hard drive for easy download later. During dolphin encounters, Matthias joins Denise in the water with a device to record synchronized video and sound that can later be compared to her recordings. What the program does is for clicks, it makes red squares. And for whistles, it makes yellow stars. When the animal clicks and whistles, it puts dots on that particular animal. So we know that this animal was whistling. That's clear there. So you could go through and score. The same way. You know, animal A made this whistle. Animal B, that would be the data analysis. I mean, that's a tool I wanted 30 years ago, but nobody could build it. And it wasn't possible. Really, now it's possible. From the beginning, Denise had been studying three groups of dolphins on the Little Bahama Bank each year. These are specific clusters that were related genetically. So we had a northern, a central and a southern cluster. But in 2013, something strange happened. We went out to our field site in May and we noticed that 50% of our animals were just not around. Now, I'd been out there for 28 years and the same individuals were resident in this area. So after about a month of looking, we finally went to the closest adjacent sandbank and there they were, all together. It's like, what are you guys doing down here? That's like a hundred miles away. The animals had crossed over 30 miles of potentially dangerous deep water to resettle on the Great Bahama Bank near the island of Bimini. So we had most of the central groups and a few individuals from the north and south moved. And we had kind of anecdotally noticed that the fish and the squid were kind of not around a lot anymore. So after thinking about it, we finally got some oceanographic data. And sure enough, after looking at temperature, wind and chlorophyll, which is a proxy for plankton production, in these different areas, we saw a pretty statistically significant drop in chlorophyll production on Little Bahama Bank where the dolphins were, which amounts to probably a big change in nutrition in the whole cycle of fish. Nowhere else did it drop, just right there. So our best guess is they moved because the fish had crashed. Now, whether it'll change back or not, I don't know. In 2016, we saw four animals came back and we were all excited. It was like, oh, maybe they'll come back if the food comes back. That hasn't panned out yet, but we're monitoring it and we'll monitor the oceanographic data too and be interesting predictor of if the system comes back. This is our southern group. You guys been studying your IDs? Anybody recognize it? Denise has been interested in exploring the non-human mind since childhood. When I was about 12 years old, I used to page through the Encyclopedia Britannica and I would always stop at the dolphin and whale page and wonder what was going on in their minds. As time progressed, she was curious about taking her communication research from passive observation to a more interactive approach. So in the late 90s, I got pretty interested in attempting some two-way work with the dolphins, primarily because the dolphins were showing us signs that they kind of wanted to go further. They would mimic our behavior. They'd try to mimic our sounds in the water. And I thought, wow, wouldn't it be interesting to give them a tool to see where it could go? But, you know, I was pretty cautious. It's a pretty wacky thing to a lot of people, I think. I queried a lot of colleagues to see could we do it. And all except one of them said, well, you've got a situation where they're curious about you in the wild. You know, you could potentially develop something. So I actually recruited Adam Pack, who came out from one of the premier cognitive labs for dolphins, because he had really great ideas and his lab had done a lot of neat experiments. In 1997, I was the associate director of the Kewalo Basin Marine Mammal Laboratory in Honolulu. And there we were studying dolphin intelligence, dolphin cognition, and all of its facets. And one of the things that we were able to show is that dolphins could appreciate the core attributes of any animal.