Fairhope High School, Fairhope, Alabama
May 21, 2009
Chasing Ellie and Student Questions Answered by the Experts
Whale #8 or "Ellie" had been tagged and we were continuing to track her throughout the night. Everyone was assigned two-hour shifts to stay on the bridge and listen for the "beeps" each time she surfaced and record data. Roland had a four-hour shift, and I told him that I would come up and give him a break from 1-2 a.m., as I did not have an assigned shift. I came up at 1 a.m. and there was not a chance for a "break" for Roland or Reny. Ellie was being a trickster to follow. She had gone out of the confines of Lester Cove and Andvord Bay and was heading out towards the Gerlache Strait or Errera Channel. We were at the fork in the road and had to decide which way to direct the mate to steer the ship. Roland decided we needed to call in for support - go wake up Alison for assistance. She came up to the bridge and confirmed that we should head towards the Errera Channel and then spin to get a better reading on the transmission of the radio signal. The Errera Channel is a narrow channel that required waking the Captain to give the "OK." Boy, this whale was waking up everyone! Captain Joe came to the bridge and gave the okay. Ellie was obviously on the move because she was coming up for two to three "beeps" and then going under for about nine minutes, but we were following the right path. Going through the channel was beautiful with the moonlight out on the snow of the cliffs that shot up on either side. At 2 a.m., Pat came up to relieve Reny and was brought up to speed with Ellie's antics. None of us wanted to leave the bridge, though without knowing what was going to transpire. You do not want to ever lose the animal on your watch (reference "Dave Johnston's stages of whale tracking" on the Duke blog - www.nicholas.duke.edu/antarctica). We continued to track her through the Errera and at 4 a.m. Dave and Elliott came to the bridge for their shift. By that time we had a strong signal on her and passed the torch. Phew! Back to bed I went!
At 8 a.m. I went back to the bridge and learned that Ellie kept it interesting through the morning hours by going out of the Errera and into the wide open Gerlache Strait. The tag was set to release at 9 a.m. (usually takes an hour) and we could pick it up at about 10 a.m. We still had the beeps, but did not have a visual as the sun started to rise between the clouds. At 9:20, we started to get the continuous beeps that indicate it has been released and is off the animal. With the wind whipping over the water, we all began to look through the binoculars for the needle in the haystack. Although in this case, the needle was a small white plastic container and the haystack was the vast Gerlache Strait! Doug went outside with the antenna and the headphones and narrowed down the direction for which to look. Finally we had a confirmation from the back deck and it was fairly close to the starboard side of the ship. Chief Mate, Rick was steering and got us right up on the tag, so the MTs could scoop it up in a net. It was an impressive production with a successful end! Yeah! Now the lengthy process of downloading the data from the tag started.
Meanwhile, I got questions from my students at home for the scientists to answer about the whale tagging. Great information with which to finish out their last day of school!
Q: How are you tracking and tagging the whales? Are you estimating according to migration routes? (Lydia Miller)
A: We are using a tag that records sounds, dive depths, dive times. It is attached to the whale with suction cups near the dorsal fin. Each time the whale surfaces and the tag is out of the water it emits a "beep" or "chirp" that is transmitted via radio waves to a receiver set to the channel of the tag. Based on the strength of the sound and adjusting the gain on the receiver, and whether it is coming more into the left or right (we have two on the bridge [top control room] of the ship, one on either side - port and starboard) to be able to narrow down the exact location of the whale.
As far as your question of the "estimating according to migration routes," these scientists were very concerned on our way down to Antarctica that they would not even get to SEE a whale because they were under the impression from other scientists that the whales had moved out of this area for the winter season. They were astounded when on their first trip out they discovered hundreds of sightings in Wilhelmenia Bay and were able to tag and track six whales in the first 12 days. It was a huge discovery!
Q: What do you enjoy more, whale tagging or studying icefish? (Jill Strachan and Alex Fultz)
A: They are truly equally amazing and totally different learning experiences! Pulling the fish pots out of the water on the back of the ship in the 40 knot winds in the middle of the night was super exhilarating and working in the lab doing the dissections and tissue collection was such a great experience for me. Knowing that these fish are the ONLY adult species of vertebrates that do not have hemoglobin on the planet is incredible. On the other hand, getting out into the Zodiac boats to be within feet of the normally elusive minke whales, penguins and seals is awesome. Not to mention getting to tag and track humpback whales in all their enormity is a once in a lifetime as well. Both experiences have been more than I could have ever dreamed they would be and make me appreciate the essence of science research all the more! Trying to absorb all the information from these scientists that I can is definitely a goal while I am here. Every day in Antarctica has brought new surprises and learning opportunities for me.
Q: What are you hoping to learn by tagging the whales? (Fletcher Pittman)
Answered by Doug Nowacek of Duke University and chief scientist of this project.
A: Fletcher, glad you asked because it gives me a chance to talk about one of my favorite subjects...the behavioral ecology of cetaceans. First, behavioral ecology is an area of research that is focused on studying and understanding the behavior of an animal within the context of its life and environment. For example, to study the foraging ecology of whales, we need to know what they are doing while underwater and just how that behavior relates to the prey they are trying to catch. A humpback whale feeds primarily on krill and small fish. To do this, the whale takes large gulps of water filled with prey, and then it uses its baleen plates to strain the prey out of the water. So, this is where the tag comes in. The tag, using accelerometers that sense the movement of the whale, records the movement or behavior of the whale as it tries to catch the krill. So, when we get the tag (and the data it carries!) back, we can analyze those movements and know when the whale was feeding! Then, we put those data together with our measurements of the krill and we will try to assemble a picture of the foraging ecology of the humpbacks!
Q: How do you track the whales you tag? How often do the tags fall off? (Robert Baugh)
Answered by Alison Stempert of University of Hawaii Institute of Marine Biology.
A: Hi Robert, tracking the whales can be very challenging, but is a really important part of the process! During the day, we try to stay with the tagged whale in a small boat -- far enough away that we don't affect what it's doing (usually a few hundred meters), but close enough to record its behavior and location. We pay attention to how long it is diving and what its behavior is like at the surface, and based on our experience following other whales, we try to predict where and when it will come to the surface between dives. Whales are not always predictable, however, so we have another method of tracking -- the tags have a tiny transmitter in them that emits a radio frequency. We have receivers that pick up this signal and play a "beep" every time the whale is at the surface and within range, just like a marine radio you might use on a boat. The beep is louder if your antenna is pointed directly at it, so we can figure out the direction the tag is from us. This is also how we find the tag once it has come off the whale and is floating at the surface.
The tags come off the whale every time we put them on -- we actually have to get the tag back in order to get any of our data! Then we can re-use that same tag. Usually we program them to come off at a certain time (the tags have a system where the salt water corrodes a tiny piece of wire, which allows air into the suction cups so they let go of the whale's back). However the tags can also get rubbed off by other whales, or they might fall off if the whale swims really fast or jumps out of the water. Thanks for your questions!
Q: What is the average population of whales in the Antarctic waters? (Dana Dowell)
Answered by Dr. Dave Johnston of Duke University.
A: Hi Dana, that is a good question, and one that our group - and many other researchers - are trying to answer with trips like this one.
In our case, we are studying primarily humpback whales and counting them from the ship as move from place to place here in the Western Antarctic Peninsula. From the preliminary analysis so far, it seems like the density of humpbacks in our study area is really high. Overall, the average density of whales in our area is just under five whales per square mile. However, we've been to one bay - Wilhelmina Bay - that has over 13 humpback whales per square mile in it! However, we have a lot more work to do to figure out how many humpbacks there are across all of Antarctica.
Q: What is the cause of the humpback whale being endangered? Is it the killer whale or fishermen? (Marcus Alford)
Answered by Andy Read of Duke University.
A: Humpbacks, like many of the great whales, are not endangered due to any modern cause. Instead, their decline was caused by uncontrolled hunting early in the 20th century. Humpbacks were one of the first species to be hunted in the Antarctic, starting around 1910. More than 200,000 humpback whales were killed in the Southern Ocean in the 20th century, mostly for their blubber, which was rendered into oil and used in all kinds of products, including margarine. At least 40,000 humpbacks were also taken illegally by Soviet whalers in the 1960s. The good news is that these whales are now protected and recovering from these past hunts. The humpbacks we see here along the Antarctic Peninsula probably breed either in Ecuador or Brazil - both of these populations are now growing, although they are still much smaller than their original size. I would like to be able to travel back in time to see what our study area looked like before so many whales were removed...
Q: Are killer whales really dolphins? If so, why are they called whales? (Ashton Johnson)
Answered by Reny Tyson of Duke University.
A: Hey Ashton, great question! Yes, killer whales are actually dolphins even though their common name is killer "whale." You see, all whales and dolphins are in the order Cetacea, which is divided into two main suborders: Mysticetes and Odontocetes. Mysticetes include all cetaceans that have
baleen instead of teeth. Baleen is an elaborate filtration system in a whale's mouth that serves to filter prey from large volumes of seawater. Baleen consists of several hundred individual plates of dense hair that hang down from the upper jaw and serves as a strainer for food. Mysticetes include blue whales, fin whales, minke whales, bowhead whales, right whales and more.
Odontocetes on the other hand, include all toothed cetaceans and is further divided into the dolphins and porpoises. Dolphins and porpoises are differentiated by several means including the shape of their teeth, the animal's size, and the shape on the animal's beak. Killer whales, and all other dolphins, have undifferentiated conical shaped teeth, are generally larger in size, and have a protruding beak. So yes, I agree it can often be confusing that killer whales are called whales when they are indeed "dolphins," but this is a common occurrence with the common names of many cetaceans. For instance sperm whales also actually have teeth and are considered members of the suborder odontoceti. Even pilot whales, false killer whales, beaked whales, and many others belong to the odontocetes. Thus having the term "whale" in one's common name does not
mean it is actually a Mysticete. It's best just to think of all cetaceans, therefore, as those that have teeth and those that do not.
Thanks for the question!
Q: How do you identify the types of whales? (Tripp Drummond)
Answered by Lindsey Peavey of Duke University.
A: Here is a long and rambling answer to the question assigned to me:
Hi Tripp, good question! It's hard to identify marine mammals at sea, especially whales and dolphins, because most of the time we only see a proportionally small part of their bodies each time they come to the surface to breathe. Also, sometimes we are several hundreds of meters away from the animal, so we have to focus on the few body parts we can see in order to make a positive identification. For whales and dolphins, generally we see either the blow or the backs of the animal just at the surface. We can use both of those things to ID the animal. For example, humpback whales have tall (2-3 meters high), V-shaped blows that are very distinct from the other whales we see in this area: Minke whales rarely have visible blows, Arnoux's beaked whales have smaller, bushier and forward projecting blows; and killer whales have low, vertical bushy blows. Also, we can use the shape, placement and coloration of the dorsal fin for ID. Humpbacks have thick, nubby dorsal fins that sit on or just posterior to a hump on the animal's backbone. These dorsal fins vary in size and shape, and can have distinctive scars, nicks, and barnacles present that we can actually use to ID individual whales. The dorsal fin of a humpback whale is very distinctive, as is the very gray color of its back, and how far back the dorsal fin sits from its blow hole on top of its head. Humpbacks also have very white, long flippers that can be seen underwater. Sometimes Southern Right whales can look similar to humpbacks at the surface, but their body color is slightly darker and Southern Right whales don't have any dorsal fin at all, so that makes it easy for us to tell the difference, even if we only see the animal's back. If we get closer, there are even more distinctive features such as the arched shape of its mouth and conspicuous whitish/yellowish callosite clusters on it's head and chin. Killer whales have very triangular-shaped dorsal fins that are very apparent and rigid as the animal surfaces. There are 3 types of killer whales found in the Antarctic (Types A, B & C), and both their body coloration and size helps us distinguish which type they are. Minke whales (which your teacher got to see up close and personal on the small boat!) have a more petite and very falcate (trigger-shaped) dorsal fin that sits farther back on its back than a humpback's, and they clearly lack the 'hump' that humpbacks have. Minke's are also a more blue-gray color on top with a whitish belly, and their skin is very smooth looking. A secondary feature we can look for are the flukes, or tail, of whales. Humpbacks usually arch their backs and show their flukes when diving, however minke whales rarely show their flukes while diving. Humpback whales have highly variable and individualized ventral (underside) flukes- scientists use these unique patterns to identify individual whales.
These are only a few of the distinct features of some of the whales and ocean dolphins we see, but generally we look specifically at dorsal fins, blows, and body coloration for species identification. It's important to 'do your homework' before surveying an area by reading any literature that has been published on the range of animals, so you know what you can expect to see before beginning to look, and how to identify them. If the animal is very far away, or if we only get a brief glimpse at the animal through our binoculars, we may be unable to ID the animal, and in that case we record it as an unidentified whale or dolphin. Taking pictures whenever we can get close enough to the animal allows us to go back and take a more careful look at the animal to confirm species identification, as well as study the individual features. For whales that can be identified to the individual (i.e. humpbacks, killer whales), catalogs exist for each region with the equivalent of 'mug shots' of each whale, so different scientists can compare photographs and try to match the whales they've seen with ones seen before. This provides a spatial and temporal 'stamp' that is very useful to make inferences about their behavior. We can learn a lot about a whale's movements, migrations and behavioral ecology by observing what is called 'mark and recapture' (seeing the same animal twice or more over time and recording its location, etc.) and social behavior (What other whales is it with? Where is it going? Is it staying with the same group of animals or moving between groups?).
Being able to identify a marine mammal correctly is very important. We know so little about whales that often times even the literature is unclear about their geographical ranges, so each sighting can be critical. For example, in many of the Antarctic guide books, it does not show the Antarctic Peninsula (where we currently are) as being part of the Southern Right whale range, but we've already seen three S. Right whales! Also, very little is known about Arnoux's beaked whale range and distribution, and we saw a very rare sighting of a group of about 60!
Q: What is the largest whale you have tagged?
Eletta Revelli, a whale scientist from Lake Como, Italy, answered this.
A: I have tagged the fin whale in the Ligurian Sea, which is the second biggest animal of the world. In the Mediterranean it can reach a length of 20m (60 feet) while in the rest of the world it can be longer, up to 25m (75 feet). That was my master thesis and we were not putting D-tags but v-TDR.
Q: What is the pattern of migration for the whales or do they stay there all the time? (Evan East)
Answered by Ari Friedlaendar of Duke University.
A: Evan, this is a great question, and one that we are trying to better understand ourselves. As far as we know, the humpback whales that spend the summer months feeding around the Antarctic Peninsula migrate to breeding and calving grounds on both sides of South America.
There has also been at least one record of an animal from this area found on the breeding grounds of American Samoa (very far to the north and west!). However, the majority of the whales probably migrate to the tropics on the west side of South America, and to Brazil on the east side of the continent.
Q: Do you tag only adult whales? (KC Miller)
Answered by Ari Friedlaendar of Duke University.
A: Hi KC, this is also a very good question. We do try to tag adult whales only. Humpback whale calves stay with their mothers for about one year, and are much smaller, so they are fairly easy to notice. We do see a fair number of juvenile animals that are not yet fully grown. There are several reasons then why we tag adults only (and only adults without a small calf). We are interested in understanding how the whales feed and go about finding food, and whales that are too young to feed on their own, or mothers that have a small calf with them, probably spend most of their time and energy with each other, and may not be the best examples of how other whales are feeding. As well, while the tag is harmless to the animal, it may cause a small amount of stress when it is put on. Since the whale does not know it is going to be tagged, sometimes they get startled, and we have decided that young whales need not experience this.