The first day of the ONR (Office of Naval Research) conference was absolutely chock full, 7am till 11pm at night. About 20 of us scientists, plus the 3 Navy guys who run the marine mammal program (and also a curious NOAA person sitting in a corner "spying", as he put it). The bulk of the day was a series of 20-minute talks. Basically, everybody at the workshop got up and summarized what they've been working on recently, one at a time. (My own talk was on right whales and also on my recent sea turtle stress research, which uses some techniques applicable to marine mammals.) Since the 20 people in the room are basically everybody who's studying stress in marine mammals, worldwide, what the Navy guys were getting - and what they wanted - was a great summary of the state of the art in marine mammal stress research.
Despite a severe case of jet lag and sleep deprivation, I can safely say that this was the single most interesting day of scientific talks that I can ever remember attending. (At most scientific conferences I start to space out about halfway through the day. But today I was riveted, right to the last talk.)
So, next I'll post a few summaries of the ongoing research projects that people were describing. First up: Dorian Houser's dolphin experiment
******
Talk #1 - Stress indicators in dolphins
Of all the experiments described today, this one was the one that will most directly answer the question of: Does sonar atually stress ut a dolphin? Dorian, the fellow giving this talk, has what some (including me) would consider to be a dream job: working with the 70 tame, trained bottlenose dolphins kept by Navy dolphin trainers at their facility in San Diego. "We've got known life histories, they're trained, they'll wear harnesses, we can get voluntary blood samples." he said. For a physiologist, that is a dream situation. (The blood samples are taken from the tail - the dolphins know they will get a fish if they turn upside down and put their tails in the trainer's hands).
Yes, the Navy has 70 bottlenose dolphins. They also have about 30 sea lions. They used to have pilot whales and killer whales and belugas. They've had marine mammals for a long time, originally to study their swimming mechanics and streamlining (for torpedo design). Then later they realized dolphins could "assist the Navy with various activities", as Dorian rather mysteriously put it. I've read a few books about this, including one written by a former Navy dolphin trainer and the "activities" are just what you would guess: dolphins can find things on the ocean bottom, and can scope things out. (They don't use dolphins for offensive warfare - because dolphins can't distinguish friend from foe! They're just trained to find and tag things.) Mostly they are trained to search for ocean mines and swimmers (downed friendlies, enemy spies). My general impression from reading the books is that the Navy seems to treat their animals well. If they didn't, the animals would just take off, since many of the animals work in open ocean, in completely free situations and could leave at any time.
The dolphin training at the Navy, like dolphin training anywhere, works entirely by positive reinforcement. A dolphin will do just about anything for a fish. Dorian got onto an interesting tangent at one point about how many fish a dolphin needs per day, and how many fish he is allowed to use to "pay" the dolphins to participate in the sonar experiment. The classic dolphin-training approach is to use a small percentage of the dolphin's daily fish needs for that day's training activities - but only a small percentage, meaning, the animal won't starve if it choose not to participate. Typically, if the dolphin doesn't choose to participate in the activity, they get all of their remaining allotment of fish anyway at the end of the day.
Dorian said that you can gauge how much a dolphin likes or dislikes a certain activity by how many fish it demands to do the activity. (or, to put it more precisely, what % of the animal's baseline food intake comes from training.) Some activities just cost a lot of fish. Apparently dolphins have a finely calibrated sense of economics, and fish is the currency of choice!
Interestingly, sonar does not "cost" much to dolphins - most dolphins are willing to sit and listen to a sonar ping for relatively few fish, and don't have to be very hungry to be willing to take part in a sonar experiment.
So here's Dorian's study design. He hasn't done the experiment yet - it's all designed and ready to go. As you're reading this, think about: What do you think of the study design? Could anything be improved? Are there any flaws?
He's got 30 dolphins and 15 sea lions lined up for this experiment. Every animal is already trained on an "ABA task", which means that they know that they are supposed to start at a certain position in the pool (position A), swim to position B and touch a paddle, and then swim back to A.
In the middle of this task, Dorian is going to play a very brief, fraction-of-a-second, very loud, sonar sound at them. PING! He's testing several different decibel levels, ranging from loud to louder to extremely loud. Each animal will hear just 1 of the decibel levels. And then he'll watch, basically, for signs of distraction and annoyance. Stress, in other words..
So how is he planning to measure that ever-so-amorphous concept of "stress,", in dolphins and sea lions? Here's what he's planning to look at:
1. Distractability. Do they complete the ABA task in the normal amount of time? Might they abandon the task entirely?
2. Do they change their behavior in any other way? "We'll especially be looking for chuffing and tail slaps," Dorian said. Apparently that's what a dolphin does when it's annoyed or agitated. (I wanted to ask what "chuffing" is, but didn't get a chance.) Dorian's got cameras mounted all around and above the pool, plus a microphone running above water - there will be dolphin trainers will be stationed around the pool, calling out verbally when the dolphins dive or do any behaviors that the cameras might miss. There will also be underwater microphones (hydrophones) to pick up any vocalizations the dolphins make themselves. I was impressed at the pool set-up (he showed us photos) and I was also grateful that I am not going to be the person who has to go through all the recordings!
3. Heart rate. There will be ECG heart rate monitors strapped right on to the dolphins! (just like we use in physiology lab at UP - except the 3 electrodes are stuck on with suction cups.). When you are stressed or scared, of course, your heart rate speeds up. The same thing happens in any mammal. It's the hormone epinephrine - also known as adrenalin- that's doing that. BUT, there's a big complication in marine mammals: heart rate plummets when they dive. It can drop to shockingly low levels in deep divers on a long dive, as low as five beats per minute in certain species. Then it speeds up to above normal when they first surface. Dolphins are only "surface divers," meaning that they don't go deep, but, even so, their heart rate definitely drops a bit. So, Dorian's going to have watch when the animals are diving, how long they've been under, whether or not they've just surfaced, and he'll have to factor all that in to the analysis of the heart rate data.
4. Stress hormones. He's planning to take blood samples (every sample paid for with a fish or two, of course) at several times: several days prior to the event (to establish that animal's baseline), immediately after the event, and one week later. He'll assay these samples for epinephrine, glucocorticoids, and several other measures too.
What do you think? What would you do differently? A bigger sample size would always be nice, of course, but thirty dolphins is the best sample size I've ever heard of for a controlled experiment with captive marine mammals.
I love this study. It's perfect. It's exactly what we need! The rest of us can just go home! In fact, I want to go to San Diego to watch! Trained dolphins and sea lions... That he can get blood samples from... I couldn't get over it. I kept muttering to myself "Thirty trained dolphins wearing harnesses." (It's the contrast to the impossibility of getting a blood sample from a baleen whale that was so entrancing. I work on baleen whale physiology, which is pretty much an exercise in frustration from start to finish. It's like trying to study Martians. You can't capture them, you can't even see them, and sometimes you wonder if they even exist at all. And a baleen whale is the only type of animal, on the entire planet, that cannot be captured alive.)
I can see one thing that could be added to the experiment, though, which is to grab fecal samples too! In many marine mammals, such as the baleen whales, we can only get fecals, never blood. (And sometimes small changes in stress hormones show up only in the feces and are not detectable in blood.) If we're going to want to extrapolate the results of this dolphin experiment to other species... well, it would be great this experiment included fecal hormone!
So later that evening, when we're all at dinner and the wine is flowing freely, I lean over to Dorian and say "You must get poops! You have to get poops. Please get poops from your dolphins!" We get into a discussion about feasibility: what consistency are the dolphin poops, anyway? What do they look like? How "scoopable" are they? I'm shouting all this across Sam Wasser, who is sitting between us (Sam being the guy who invented the poop hormone assay technique, and also the guy who found a way to get DNA out of elephant ivory, but that's another story.) So Sam chimes in with a great design for a poop-scooping Pepsi bottle device that he's been using with free-swimming killer whales in Puget Sound. That's it. That'll work great.
Dorian then says to Sam & me, "Hey, you want to do anything with these dolphins? We've got 70. They wear harnesses and everything. Whatever you want to do. Let me know." SEVENTY TRAINED DOLPHINS! Are you kidding? We could test all our fecal hormones - see if they correlate to blood - test the new thyroid hormone assay - do an ACTH challenge - I've immediately got a dozen ideas. Here's hoping.
I'm muttering "Seventy trained dolphins wearing harnesses," under my breath for the rest of the evening.
Saturday, November 7, 2009
Thursday, November 5, 2009
Navy sonar: Background
Imagine that you're a dolphin peacefully swimming through the sea, with all of your buddies, happily hunting fish. You're squeaking and whistling to your friends, communicating all sorts of information to them, and they're squeaking and whistling right back. You're also echolocating to find the fish - you're making constant little "clicks", and all around you, you can hear echoes of the clicks coming back from the fish that you're trying to catch. You're also keeping an ear open for killer whales.
In a nutshell, you're exquisitely sensitive to every sound in the sea.
So you're swimming along, and all of a sudden:
BONG!!!!!!!!!!!!!!!!!
... the loudest sound that you have ever heard in your life blasts out from a U.S. Navy ship a mile away. You're so dazed afterwards that you can't seem to hear right.
What happens next?
Nobody knows!
---------------------------------------------------------------------------------------
The U.S. Navy periodically uses a type of sonar that is so loud that there has been a concern that the sonar might affect, or even kill, marine mammals that are near the ships. It's called "low frequency active sonar", and its purpose is primarily to detect quiet submarines. Navy ships emit these sonar pings at astonishingly high decibel levels - up to 180 dB and higher, sometimes over 200 dB. If you were sitting in the water next to one of this ships, the sound level would be the equivalent of standing next to a NASA rocket at takeoff. But just for a fraction of a second, which is how long the "ping" lasts.
When the Navy started using this kind of sonar, there occurred some "mass strandings," events in which whole groups of whales (usually a type called beaked whales) suddenly piled up on beaches - and died. This happens occasionally all over the world; there are always some mysterious mass strandings that happen for unknown reasons. It's always been a puzzle what causes mass strandings. But in a couple of cases, the strandings occurred directly after a Navy sonar exercise nearby. So the Navy started to come under increasing public pressure to demonstrate that they were not harming marine mammals.
In conservation biology terms, the Navy is creating a unique type of habitat degradation - acoustic disturbance. It's not a contaminant, it's not pollution, it's not a fishing net. It's just noise. But it's VERY LOUD noise, and it's not natural for that environment. What might it be doing to the animals?
The first suspicious strandings were noticed in the early 1990s, and since then the Navy's been focusing on this issue more and more. They now have several people working full-time, year-round, on "the marine mammal problem", as they call it, looking for a "solution" - by which they mean, a clear answer, about exactly what volume of sonar causes exactly which problems in marine mammals, at exactly which distance, and exactly how that affects the animals' health, welfare, reproduction and survival afterwards. They need a clear answer in order to know how much they need to quiet down their sonar pings, and under what conditions they shouldn't use sonar at all.
Yesterday I talked to the guy who is in charge of the entire Navy marine mammal program. He told me "You wouldn't believe how far the Navy's come about awareness of this issue. I've been working on this since maybe the mid 90's, and I talk to everyone in the Navy, from the top down. I talk to the secretary and all the generals. At this point, every single four-star general in the Navy, every single one of them, knows all about the "mammal issue". When I walk through the Navy offices, people all know who I am and what I'm working on - they're always calling out 'Hey, it's the mammal guy! Hi mammal guy! Mammal guy, have you solved the problem yet?' "
He added, "And I always say 'Not yet.' "
He went on, "They started off giving me a budget of $700,000 a year to fund research on this problem. That was ten years ago. Now it's $10,000,000 a year."
Actually this coming year it will be $12,500,000. They keep doing more and more research, because the "clear answer" they're seeking gets more and more murky.
Interestingly, the Navy's already solved the major problem: Stopping the strandings. Quoting again from my new Navy friend (paraphrasing, actually - I didn't have a tape recorder so this is from memory): "There's no doubt those couple of early strandings in the 90's were caused by us. We caused those strandings. That was our fault. Clearly. So I studied everything about those events and I made up a list of the conditions that had contributed to the strandings. And now we use that list to decide when not to use sonar."
I asked about the "conditions" and he started reeling off descriptions of exactly which stranding, where, in which year, was related to sonar, and every single detail about each of those strandings - from the number of animals to the species to the weather that day. It became apparent that he knew, by heart, the details every single marine-mammal stranding event in the world in the last 20 years (so did most other people nearby, who were chiming in details like, "Tell her about the Canary Islands!" "Tell her about the melon-headed whales!").
He concluded with: "Here's my list: A deep, narrow channel with no egress. Whales in the channel, especially beaked whales. A shallow ramp out of the channel that goes up to a sloping beach. Three Navy ships cruising back and forth at the other end of the channel. Multiple ships all doing the sonar at once." That'll cause a stranding, he said.
I asked, what's Navy policy now?
He said: "What has happened is, I got them to use my list, and today it is FORBIDDEN in the US Navy, it is absolutely VERBOTEN [you could hear the capital letters in his tone of voice], to do a sonar exercise when those conditions are in place. The conditions of my list. We absolutely never use the sonar in that situation. And we have not had a single mass stranding in ten years caused by the U.S. Navy. That is, not counting those events where a mass stranding occurs for some other reason and the media all says "Oh, there was a Navy ship here doing sonar exercises only a month ago, a thousand miles away, so it must be due to that!" That is the most frustrating thing.... Yes, there have been mass strandings caused by navies recently, but it's not the US Navy. It's the European navies! Because the European navies don't use my list. Actually they don't really have any tough sonar regulations in place. They don't have a clearly defined set of criteria of exactly when they must not use sonar."
He added one more detail: "Oh, and, if we're doing a sonar exercise in any other location, if there's any marine mammal sighted, the sonar is turned down, and if it swims closer to a certain level it's turned down further, and further."
So I asked if a dolphin could "turn off" a Navy ship entirely just by swimming right up to it, and he said "Yes, sure, that happens sometimes." (And I wondered whether some dolphins might actually learn to do that on purpose.)
So here is my impression of where it stands right now: The mass-strandings are not happening any more (not with our navy, anyway), and the Navy's got a pretty good policy of not using sonar, or turning it down, when marine mammals are known to be nearby. It's also become apparent, after an immense amount of testing, that the sonar doesn't kill the animals outright and (at the levels and distances typical in the sea) does not physically damage them. Or as he put it "The sonar's not a Death Ray. It's really not."
But - even if they're not dying, even if they're not stranding, couldn't the sonar still be affecting the animals somehow? Basically: does it STRESS the animals, in some way that might affect their health or survival later?
For example, consider these three possibiltiies:
- Hearing. Loud sonar has been shown (by Navy-funded research) to make a dolphin's hearing less sensitive temporarily. It's called a "Temporary Threshold Shift" - a temporary shift in the threshold of hearing. It's the same effect experienced by a person who spends all night in a loud dance club, walks out on the street later, and realizes that he's shouting at his friends. Because everything sounds muffled. For the human, no big problem. But for an echolocating dolphin - could this ruin its ability to find food, temporarily? Or to communicate with its social group?
- Driving animals away. The most prominent behavioral reaction by beaked whales to sonar is simply that they stop foraging and leave the area for a few days. They just "go quiet, dive deep and leave" as one scientist put it. A couple days later, they come back, and they seem fine. But suppose the consequence was that they went hungry for a few days because of having to leave their feeding grounds. If this happens over and over, would they lose weight? Would they start starving, or not breed as often? Or - is it no problem? How can we tell if it is a problem for a beaked whale to move away for a couple days?
- Chronic stress. The most subtle effect is that loud sonar may simply cause an incresae in stress hormones. In other words, it might just "stress out" the dolphin (or sea lion, beaked whale, etc.), even though the animal might actually be physically just fine. The potential problem here is that long-term chronic stress is well-documented to interfere with health, reproduction, and the immune system.
So it has come down to this: How "stressed out" does a marine mammal feel after it's heard a loud sonar ping? And how often can a marine mammal get "stressed out" before its health, reproduction, and general quality of life really start to suffer?
At this point the Navy is groping for what to do next. They've pretty much stopped the mass strandings, they've shown the sonar doesn't actually kill the animals, but they know the public will not be satisfied with that. So they know they have to somehow tackle this vague, intractable question of: what makes a dolphin feel "too stressed out"?
So what they did was: they have invited all the top stress physiologists and all the marine mammal physiologists from around the world to come to D.C. for a two-day conference, to tell them the state of research in stress physiology, and to advise them what their research priorities should be. They sent out the call worldwide - they got pretty much every marine mammal researcher worldwide who has ever studied any aspect of stress, and they also invited most of the world's experts in general stress physiology. (I apparently got on the list because of a study I did some years ago on measuring stress hormones in North Atlantic Right Whales.) They flew us all here to Washington, D.C., paid our plane tickets, our hotel, our taxis and food and just asked us to talk to them for two days. They're going to use our advice to decide what to do with the $12,500,000 per year that they currently receive for research.
What I think they are only just realizing is that they have strayed into a research minefield. "What stresses a dolphin?" might seem like an easy question, but it's got to be one of the most difficult field biology questions possible. Because it's bedeviled by two of the most complicated and impossible questions of field biology:
(1) How can we study ANYTHING about marine mammal physiology - animals that we can't catch, can't take a blood sample from, and can't even see most of the time?
(2) How can we measure stress? What is stress anyway? What does "stress" even mean?
Poor Navy. I wonder if they know what they've gotten into! These are two of the thorniest problems in biology, and the best minds in the field have not solved either of them in over a century of trying. I once swore I would never get involved in stress research, becuase it's so difficult, so impossible to study, so impossible to get a clear answer; and I also once swore I would never get involved in marine mammals, because they are so difficult, so impossible to study, so impossible to get a clear answer.... So of course here I am at the Office of Naval Research's Workshop on Assessing Acoustic Stress in Marine Mammals.
Well, that's the background. And here we all are in DC!
posts coming next (to be written more slowly):
- summaries of some of the really exciting research projects that I am learning about
- a Navy lament, told to me over several glasses of beer at the Wednesday night social
- the Pie-in-the-Sky list: if you could have all the money you wanted to invent any new research technology to study marine mammals - if you could invent any crazy little robotic gizmo or sequence any genome, what would you do?
- What happens next?
In a nutshell, you're exquisitely sensitive to every sound in the sea.
So you're swimming along, and all of a sudden:
BONG!!!!!!!!!!!!!!!!!
... the loudest sound that you have ever heard in your life blasts out from a U.S. Navy ship a mile away. You're so dazed afterwards that you can't seem to hear right.
What happens next?
Nobody knows!
---------------------------------------------------------------------------------------
The U.S. Navy periodically uses a type of sonar that is so loud that there has been a concern that the sonar might affect, or even kill, marine mammals that are near the ships. It's called "low frequency active sonar", and its purpose is primarily to detect quiet submarines. Navy ships emit these sonar pings at astonishingly high decibel levels - up to 180 dB and higher, sometimes over 200 dB. If you were sitting in the water next to one of this ships, the sound level would be the equivalent of standing next to a NASA rocket at takeoff. But just for a fraction of a second, which is how long the "ping" lasts.
When the Navy started using this kind of sonar, there occurred some "mass strandings," events in which whole groups of whales (usually a type called beaked whales) suddenly piled up on beaches - and died. This happens occasionally all over the world; there are always some mysterious mass strandings that happen for unknown reasons. It's always been a puzzle what causes mass strandings. But in a couple of cases, the strandings occurred directly after a Navy sonar exercise nearby. So the Navy started to come under increasing public pressure to demonstrate that they were not harming marine mammals.
In conservation biology terms, the Navy is creating a unique type of habitat degradation - acoustic disturbance. It's not a contaminant, it's not pollution, it's not a fishing net. It's just noise. But it's VERY LOUD noise, and it's not natural for that environment. What might it be doing to the animals?
The first suspicious strandings were noticed in the early 1990s, and since then the Navy's been focusing on this issue more and more. They now have several people working full-time, year-round, on "the marine mammal problem", as they call it, looking for a "solution" - by which they mean, a clear answer, about exactly what volume of sonar causes exactly which problems in marine mammals, at exactly which distance, and exactly how that affects the animals' health, welfare, reproduction and survival afterwards. They need a clear answer in order to know how much they need to quiet down their sonar pings, and under what conditions they shouldn't use sonar at all.
Yesterday I talked to the guy who is in charge of the entire Navy marine mammal program. He told me "You wouldn't believe how far the Navy's come about awareness of this issue. I've been working on this since maybe the mid 90's, and I talk to everyone in the Navy, from the top down. I talk to the secretary and all the generals. At this point, every single four-star general in the Navy, every single one of them, knows all about the "mammal issue". When I walk through the Navy offices, people all know who I am and what I'm working on - they're always calling out 'Hey, it's the mammal guy! Hi mammal guy! Mammal guy, have you solved the problem yet?' "
He added, "And I always say 'Not yet.' "
He went on, "They started off giving me a budget of $700,000 a year to fund research on this problem. That was ten years ago. Now it's $10,000,000 a year."
Actually this coming year it will be $12,500,000. They keep doing more and more research, because the "clear answer" they're seeking gets more and more murky.
Interestingly, the Navy's already solved the major problem: Stopping the strandings. Quoting again from my new Navy friend (paraphrasing, actually - I didn't have a tape recorder so this is from memory): "There's no doubt those couple of early strandings in the 90's were caused by us. We caused those strandings. That was our fault. Clearly. So I studied everything about those events and I made up a list of the conditions that had contributed to the strandings. And now we use that list to decide when not to use sonar."
I asked about the "conditions" and he started reeling off descriptions of exactly which stranding, where, in which year, was related to sonar, and every single detail about each of those strandings - from the number of animals to the species to the weather that day. It became apparent that he knew, by heart, the details every single marine-mammal stranding event in the world in the last 20 years (so did most other people nearby, who were chiming in details like, "Tell her about the Canary Islands!" "Tell her about the melon-headed whales!").
He concluded with: "Here's my list: A deep, narrow channel with no egress. Whales in the channel, especially beaked whales. A shallow ramp out of the channel that goes up to a sloping beach. Three Navy ships cruising back and forth at the other end of the channel. Multiple ships all doing the sonar at once." That'll cause a stranding, he said.
I asked, what's Navy policy now?
He said: "What has happened is, I got them to use my list, and today it is FORBIDDEN in the US Navy, it is absolutely VERBOTEN [you could hear the capital letters in his tone of voice], to do a sonar exercise when those conditions are in place. The conditions of my list. We absolutely never use the sonar in that situation. And we have not had a single mass stranding in ten years caused by the U.S. Navy. That is, not counting those events where a mass stranding occurs for some other reason and the media all says "Oh, there was a Navy ship here doing sonar exercises only a month ago, a thousand miles away, so it must be due to that!" That is the most frustrating thing.... Yes, there have been mass strandings caused by navies recently, but it's not the US Navy. It's the European navies! Because the European navies don't use my list. Actually they don't really have any tough sonar regulations in place. They don't have a clearly defined set of criteria of exactly when they must not use sonar."
He added one more detail: "Oh, and, if we're doing a sonar exercise in any other location, if there's any marine mammal sighted, the sonar is turned down, and if it swims closer to a certain level it's turned down further, and further."
So I asked if a dolphin could "turn off" a Navy ship entirely just by swimming right up to it, and he said "Yes, sure, that happens sometimes." (And I wondered whether some dolphins might actually learn to do that on purpose.)
So here is my impression of where it stands right now: The mass-strandings are not happening any more (not with our navy, anyway), and the Navy's got a pretty good policy of not using sonar, or turning it down, when marine mammals are known to be nearby. It's also become apparent, after an immense amount of testing, that the sonar doesn't kill the animals outright and (at the levels and distances typical in the sea) does not physically damage them. Or as he put it "The sonar's not a Death Ray. It's really not."
But - even if they're not dying, even if they're not stranding, couldn't the sonar still be affecting the animals somehow? Basically: does it STRESS the animals, in some way that might affect their health or survival later?
For example, consider these three possibiltiies:
- Hearing. Loud sonar has been shown (by Navy-funded research) to make a dolphin's hearing less sensitive temporarily. It's called a "Temporary Threshold Shift" - a temporary shift in the threshold of hearing. It's the same effect experienced by a person who spends all night in a loud dance club, walks out on the street later, and realizes that he's shouting at his friends. Because everything sounds muffled. For the human, no big problem. But for an echolocating dolphin - could this ruin its ability to find food, temporarily? Or to communicate with its social group?
- Driving animals away. The most prominent behavioral reaction by beaked whales to sonar is simply that they stop foraging and leave the area for a few days. They just "go quiet, dive deep and leave" as one scientist put it. A couple days later, they come back, and they seem fine. But suppose the consequence was that they went hungry for a few days because of having to leave their feeding grounds. If this happens over and over, would they lose weight? Would they start starving, or not breed as often? Or - is it no problem? How can we tell if it is a problem for a beaked whale to move away for a couple days?
- Chronic stress. The most subtle effect is that loud sonar may simply cause an incresae in stress hormones. In other words, it might just "stress out" the dolphin (or sea lion, beaked whale, etc.), even though the animal might actually be physically just fine. The potential problem here is that long-term chronic stress is well-documented to interfere with health, reproduction, and the immune system.
So it has come down to this: How "stressed out" does a marine mammal feel after it's heard a loud sonar ping? And how often can a marine mammal get "stressed out" before its health, reproduction, and general quality of life really start to suffer?
At this point the Navy is groping for what to do next. They've pretty much stopped the mass strandings, they've shown the sonar doesn't actually kill the animals, but they know the public will not be satisfied with that. So they know they have to somehow tackle this vague, intractable question of: what makes a dolphin feel "too stressed out"?
So what they did was: they have invited all the top stress physiologists and all the marine mammal physiologists from around the world to come to D.C. for a two-day conference, to tell them the state of research in stress physiology, and to advise them what their research priorities should be. They sent out the call worldwide - they got pretty much every marine mammal researcher worldwide who has ever studied any aspect of stress, and they also invited most of the world's experts in general stress physiology. (I apparently got on the list because of a study I did some years ago on measuring stress hormones in North Atlantic Right Whales.) They flew us all here to Washington, D.C., paid our plane tickets, our hotel, our taxis and food and just asked us to talk to them for two days. They're going to use our advice to decide what to do with the $12,500,000 per year that they currently receive for research.
What I think they are only just realizing is that they have strayed into a research minefield. "What stresses a dolphin?" might seem like an easy question, but it's got to be one of the most difficult field biology questions possible. Because it's bedeviled by two of the most complicated and impossible questions of field biology:
(1) How can we study ANYTHING about marine mammal physiology - animals that we can't catch, can't take a blood sample from, and can't even see most of the time?
(2) How can we measure stress? What is stress anyway? What does "stress" even mean?
Poor Navy. I wonder if they know what they've gotten into! These are two of the thorniest problems in biology, and the best minds in the field have not solved either of them in over a century of trying. I once swore I would never get involved in stress research, becuase it's so difficult, so impossible to study, so impossible to get a clear answer; and I also once swore I would never get involved in marine mammals, because they are so difficult, so impossible to study, so impossible to get a clear answer.... So of course here I am at the Office of Naval Research's Workshop on Assessing Acoustic Stress in Marine Mammals.
Well, that's the background. And here we all are in DC!
posts coming next (to be written more slowly):
- summaries of some of the really exciting research projects that I am learning about
- a Navy lament, told to me over several glasses of beer at the Wednesday night social
- the Pie-in-the-Sky list: if you could have all the money you wanted to invent any new research technology to study marine mammals - if you could invent any crazy little robotic gizmo or sequence any genome, what would you do?
- What happens next?
Subscribe to:
Posts (Atom)