by Diana Reiss
***
At the Operation Humphrey meeting later that night, all hell broke loose. Dave was clearly agitated. He opened the meeting with an accusing look in my direction. He asked who was responsible for getting someone in the government to turn off the low-frequency coastal monitoring system—a system used to detect enemy vessels—on the theory that the sounds were attracting Humphrey! At the first meeting at Operation Humphrey headquarters, I had heard some rumblings from local residents who believed that Humphrey might have somehow been attracted to or influenced by the coastal acoustic monitoring system. I hadn't taken this concern seriously and therefore was quite shocked to hear that the system had indeed been turned off for a brief interval that morning while we were trying to get Humphrey under the bridge. Apparently, a rumor was circulating that a few members of the rescue team had somehow convinced the powers that be to turn it off. I was surprised to hear that the system had been turned off and also a bit angry; had we known about it, we might have been able to monitor the whale's behavior more closely. But frankly, I never understood why anyone would think that sounds on the coast would affect the whale's behavior inland. I didn't even know where these sounds were being broadcast from. I made it very clear to Dave that I had no involvement whatsoever. Ironically, this event foreshadowed the current concern that midrange sonar may be damaging to marine mammals. In fact, it is quite possible that the navy's sonar monitoring system harms whales, but at the time, the idea seemed far-fetched.
***
Back on the water, our sonorous fleet continued to herd Humphrey seaward through a succession of increasingly larger and more formidable bridges and possible barriers. With each bridge we faced new challenges. The next hurdle on our southward route was the Rio Vista Bridge, a much larger—half a mile long—steel expansion bridge that spanned the Sacramento River at the small town of Rio Vista. Before I'd joined the rescue operation, rescuers had tried and failed to move Humphrey back southward under it.
It was late afternoon when we approached the bridge. Two small roads flanked the river, and as we drew closer to the bridge, our arced fleet gripped tightly around Humphrey, I noticed a line of cars and trucks stopped on each side. It looked like people were waiting at the finish line of a great race; children were sitting on their parents' shoulders, and people were standing on the roofs of their vehicles, cheering Humphrey on.
And then it happened. Humphrey stopped within feet of the bridge and refused to move any farther. Ours was still the lead boat, and we gingerly maneuvered the Bootlegger and the other small boats around the whale and gently but firmly tried to nudge and encourage him under the bridge, but Humphrey held his ground.
And then Dave took control. He called us on our shipboard radio and told us he was coming aboard. He quickly approached the Bootlegger in a small Coast Guard skiff and boarded, carrying a small case. Without any discussion, he opened the case, pulled out a dark roundish object, pulled a pin from it, and hurled it toward Humphrey. I watched in disbelief as the object flew through the air as if in slow motion. It was a seal bomb, an explosive device that's often used in construction sites to clear the waters of unwanted marine mammals. It hit about ten feet behind the whale, sank, and detonated.
Within seconds, Humphrey began twisting his huge body; he made a sudden turn away from the bridge and swam right past us, going north, then promptly beached himself in two feet of water. So now we had a beached whale sixty miles inland!
Our rescue group from the CMMC couldn't believe what had occurred. Some key members of our team exploded in anger and quit the rescue immediately. Peigin and I were equally astonished and angry, but we felt we could not quit. We had a forty-ton whale stranded on the riverbank, and if we didn't do something fast, the physical forces acting on him would soon result in irreversible physiological damage that could kill him. This is a real danger when large-bodied whales become stranded or beached. They often have to be euthanized if they are out of the water too long.
We needed to help Humphrey survive the few hours remaining until high tide would set him afloat again. We had to find a way to keep Humphrey's entire body wet, or his skin would dry out and become damaged. I called the local fire department and asked if they could get fireboats on the river and keep the whale under a fine spray of water. Miraculously, they arrived in minutes. I watched from the bridge, and what a surreal image it was: a whale on the riverbank, with arcs of water over him, rather than arcs of boats surrounding him, saving his life.
Many of the CMMC staff were with Humphrey on the riverbank, some trying to calm him, others digging away the earth beneath him to try to get him afloat. I walked quickly along the small roadway past all the stopped vehicles and through the crowds to get to Humphrey. I was amazed at his size and presence out of the water. His forty-five-foot-long body dwarfed mine. I pressed my hand gently against his skin. It was warm and soft, like the skin of the dolphins I was so familiar with at my lab. I walked farther along and looked into his eye. I had never been this close to a humpback and certainly had never had the opportunity to look one in the eye. But now, despite our two species' ninety-five million years of divergent evolution, I felt a familiarity I hadn't expected, a pattern that connected me to him. His eye was warm and dark purplish brown, rimmed in white like ours, and he followed my movements as I walked near him. I wanted to find some way to let him know we were trying to save him—if only we had some means of communicating. But all I could do was be there with him.
I tried once again to imagine being this whale, to see the situation from his point of view. The noise levels under the Liberty Bridge were quite low, but the noise under the Rio Vista Bridge was another story. I had examined sonograms—sound pictures—of the noise levels in the waters both north and south of the bridge. It was clear there was a dreadful din just under this bridge, probably created by the traffic passing over it and somehow magnified by the metal bridge itself acting as a resonator and projecting the sound into the water. Much of the sound was low in frequency—right in the sensitive hearing range of humpbacks. It hit me: the noise from the bridge was stopping him.
Perhaps when the whale had swum under the bridge before there was less traffic and thus less noise. But now it was close to 5:00 P.M. and the bridge was packed with heavy two-way traffic. My idea was simple: To move Humphrey forward, we had to remove that wall of sound in front of him. We had to stop the traffic.
I shared my idea with Peigin, who immediately agreed that we should talk to Dave and get him to shut down the bridge for thirty minutes at the height of rush hour. Dave listened politely but then quickly vetoed the idea. It was approaching five o'clock on a weekday. There was no way he would consider creating a massive traffic jam. End of conversation.
Peigin and I were not about to give up that easily. We noticed that Senator Garamendi was standing nearby, so again we pleaded our case to him. We showed the sonograms of the bridge noise and explained how both acoustic and physical objects could be perceived as barriers by whales. He said, "I get it." He'd once been a cattle rancher, and cattle were the same way—they didn't like barriers and didn't like to pass through narrow openings. "Let's try it," he said. "I will close down the bridge."
And from that moment on, it all worked. The senator ordered the bridge closed at high tide, and Humphrey squirmed and pushed himself off the riverbank. Our flotilla surrounded him from behind, banged our pipes, and then watched as Humphrey swam right under the bridge.
***
Over the following days we continued to move Humphrey southward into larger bodies of connected waterways and into the wider and deeper expanses of the Sacramento River. Many bays dwarfed our small flotilla. It became all too clear that our arc of boats was too small. We needed more boats and we needed bigger boats.
The government sent us several more military river-patrol boats, thirty-foot-long rigid-sided vessels that we referred to as Vietnam riverboats because they'd been used to patrol rivers in the Vietnam War in the late 1960s. These versatile b
oats had fiberglass hulls and water-jet drive, enabling them to pivot sharply, reverse direction, come to a complete stop from full speed in just a few boat lengths, and operate in shallow, weed-choked rivers. They had been perfect for Vietnam, and they were now perfect for us.
The Coast Guard sent in a very large Coast Guard vessel that occasionally served as our mobile headquarters during the weeklong rescue. Our flotilla had grown into a strange constellation on the water. But even with these larger ships, we were unable to keep Humphrey from slipping through our lines. Each night we strategically positioned the military boats to block the openings of the many connecting waterways and sloughs that led back north in hopes of not losing ground and keeping Humphrey locked in position until we could commence rescue operations again in the early morning. Yet he had the uncanny ability to just disappear, vanish from sight, leaving no trace of his blows or watery footprints. We needed an even larger boat with sophisticated side-scan sonar to track our disappearing Houdini.
I called my professional colleague and friend Terry Kelly, then head of a division of the U.S. Geological Survey (USGS) in Redwood City, California. Terry had kindly provided assistance when I was building my lab, lending or giving me surplus hydrophones and other equipment that I couldn't have afforded otherwise. Like most of the San Francisco Bay area residents, he had been following the story of Humphrey. Terry knew what was coming when I called. I remember hearing him say to his staff, while he was still on the phone with me, "Okay, you guys, who wants to go help save a whale?" The next day, a massive USGS ship equipped with high-tech side-scan sonar and manned by an enthusiastic crew moved into position. I looked back at our flotilla from the deck of the Bootlegger and saw what appeared to be a moving city on the sea.
On the USGS ship was a room jammed with equipment for underwater surveying, including large screens that displayed changing images of the waters and terrain we were moving through. I was usually on the Bootlegger during the rescue operation, but occasionally I went aboard the USGS ship and watched on the side-scan sonar screen as a fluorescent green phantom Humphrey moved ahead of us. I wondered if this image was at all similar to what dolphins and other toothed whales perceived with their biological sonar as they swam through turgid and murky waters.
But even this advanced technology failed us when we tried to track Humphrey through the night. As before, every evening he would somehow ditch us, disappear off the sonar screens, and we'd have to wait for the aerial survey of the morning to locate him again. But even with our enlarged flotilla and advanced technological prowess, we could not control Humphrey's movements in these larger waters. We needed another plan. Senator Garamendi arranged a meeting in the state capitol building in Sacramento.
I arrived at the capitol building that morning and sat down at a very large conference table in what I can only describe as a war-room setting. Senator Garamendi was officiating. With us were Peigin Barrett; Laurie Gage, our veterinarian; other staff members from the CMMC; Bernie Krause, a musician and bioacoustician who had assisted in the rescue; Dave and a few NMFS staffers; and people from NOAA. Present via teleconference were several internationally known marine mammal scientists and colleagues. Among them were Dr. Ken Norris; Karen Pryor, a respected dolphin behaviorist now known for her groundbreaking clicker method for training dogs and other animals; and Dr. Louis Herman, a cognitive psychologist at the University of Hawaii and director of the Kewalo Basin Marine Mammal Laboratory.
At first we were all stumped about how best to proceed. Then Lou Herman made the brilliant suggestion of trying to attract Humphrey to the boats by broadcasting, or playing back, sounds of humpback whales. Previous attempts to attract whales using playback had met with little success. However, after a brief discussion of past failures, we realized we had a unique situation with an isolated whale, so we decided to try it. Lou said he would give us his lab's recordings of humpback whales feeding in Alaskan waters. The government would send a special transport plane to Hawaii to get the tapes and then deliver them to us in California the next morning.
Then, before I even had time to think about it, I was put in charge of doing the playback. I had never done a playback experiment; I hadn't even had much experience with humpbacks before Humphrey. I was flying blind, somewhat terrified, but I agreed to do it since I was the only acoustician and behavioral scientist on the team who worked directly with marine mammals. None of my colleagues had any helpful suggestions about how to conduct the playback, so I was pretty much on my own.
***
The technical arrangements were made easily enough. That wasn't the issue. Acoustics experts at the Naval Postgraduate School in Monterey, California, sent a few of their grad students with a special underwater speaker we would use to broadcast the whale calls from the Bootlegger. But I puzzled over what method to use—how exactly to do the playback.
I went to my lab and sat by the dolphin pools to ponder it all. I watched Circe and her calf Delphi and Terry and her calf Pan as they interacted, listening to their vocalizations over my headset. In my years of watching dolphins in my lab, I'd been struck by how quiet dolphins were when they were close together. At times, the pools would be filled with a diversity of whistles, squawks, echolocation clicks, and other sounds that humans have yet to decode, but there were often long stretches of complete silence when the dolphins were interacting or in mother-calf pairs swimming closely together. As I continued to watch the dolphins, I kept thinking about the playback. Wouldn't Humphrey just check out the sounds, recognize their falsity, and leave? Would he ignore or just get bored with the sounds? How could we use the sounds to keep him with us?
And then, the dolphins inspired an idea. I had observed it so often; it was so simple. Dolphins often produce contact calls when they are separated from each other, and then one or the other re-approaches, and they come together. I had seen it used among larger groups of adult dolphins, between Circe and her calf Delphi, and between Terry and her calf Pan day in and day out. That was it! I would use the playback calls like contact calls; I'd broadcast them to Humphrey when he wasn't near us, and stop broadcasting them when he was with us. It was a hunch, and frankly, it was the only idea I had at the time.
At six in the morning on November 3, I arrived at the dock where the NMFS officials and the CMMC staff were assembling for the event. The Bootlegger and a few smaller Coast Guard Zodiacs were already there. The students from the Naval Postgraduate School were making the final adjustments to the speaker system they had installed the day before. The other boats were out of sight, waiting upriver. I had requested that the rest of the flotilla be at least five hundred to a thousand yards behind the Bootlegger in order to give us and Humphrey a little personal space. Humphrey's location was unknown, despite the aerial searches to find him.
***
I motored upriver in a Zodiac with my monitoring equipment to test and adjust the broadcast level of the sounds to be used in the playback. After dropping my hydrophone in the water, I radioed the okay back to the Bootlegger to broadcast the test sounds. As I heard the haunting whoops and deep hurumph signals of the feeding humpbacks, I noticed a whoosh of water and movement. Humphrey had appeared out of nowhere and was making a beeline toward the Bootlegger! We raced past him in the Zodiac, got to the Bootlegger, and jumped aboard. Operation Playback had begun.
I stood at the stern of the boat, my eyes fixed on Humphrey as we moved slowly away from the dock and into the deeper waters of San Pablo Bay. Humphrey followed us like a lost puppy. When he was with us, he stayed within five to twenty feet of the boat. I watched his subtle movements, reading his body language, looking for any cues that might indicate that he was about to depart. If it seemed like he was staying, I would signal to stop the broadcasting. If Humphrey began to drift away, we would broadcast again, and he would re-approach the boat. I was thrilled: this was actually working! From the upper deck of the Bootlegger we recorded how long we played the sounds before the whale approached the boat and how long he stayed with u
s once we stopped broadcasting. Humphrey's behavior changed noticeably—he went from a whale swimming around aimlessly to one who had a focus. It was as if he had met a long-lost friend.
We moved the whale about forty miles in four hours, and all was going well. Then a brief episode of tension occurred when Dave radioed from one of the boats in the flotilla and asked us to stop and take a short break. His request made no sense at all to any of us on the Bootlegger; given our success with the playback and the whale's momentum south, we wanted to keep up the pace. But Dave was in charge, and I was ordered to take a break.
The Bootlegger slowed down and stopped, and so did Humphrey. It was then that Dave's real intent became clear. Dave approached in a Zodiac holding a stick with the same barbed radio tag we'd seen earlier. He planned to radio-tag Humphrey now that the whale was trapped between Dave's boat and ours. I called out and told Dave to stop or I would leave the Bootlegger and not continue the playback.
Suddenly we were in a standoff. I held my ground and stated that in my opinion, the whale saw the boat and heard the sounds we were playing as a positive stimulus—our playback was working. Sneaking up on Humphrey and attempting to radio-tag him with a device that we'd all agreed was not well developed and might only stress him more would jeopardize the operation, the whale, and the people aboard the Bootlegger.
It was very tense out there on the water for several minutes, but fortunately the NMFS officials back at Operation Humphrey headquarters radioed us to say that they thought we should not risk losing Humphrey's trust and that we should continue with the original plan.
Finally, Dave agreed to proceed with the playback. He seemed to relax, and he said he wanted to join us. He jumped aboard the Bootlegger, and we continued to move the boat southward, Humphrey following us closely. Between that day and the next, we traveled sixty miles, heading toward the final gateway to the open ocean, the Golden Gate Bridge.