Question of the Week: Dolphins and Whales on the High Seas

Every week during the HICEAS research mission, our scientists answered one question from students and the public. Thanks to all everyone who submitted questions!

Bottlenose dolphins

Bottlenose dolphins (Photo: NOAA Fisheries/Adam Ü)

Question: Why are large scale surveys like HICEAS so rare when they seem to be quite important and interesting? — Jessica (Honolulu, HI)

Answer: HICEAS 2017 was the first survey of its kind in Hawaii since 2010. These surveys are rare because our study area is huge (1.8 million square nautical miles) and planning, funding, and conducting a survey of that scale takes a great amount of effort, coordination, and ship time. We need around 180 days at sea for HICEAS, but have only one ship equipped to conduct marine mammal surveys at our NOAA Fisheries lab in Hawaii (the Pacific Islands Fisheries Science Center), and that ship is also needed for other important at-sea fisheries research. We must also conduct the survey at the same time each year (summer and fall) so the data are comparable. To pull it off, we partnered with our sister lab in San Diego (the Southwest Fisheries Science Center). We also partnered with the U.S. Navy and the Bureau of Ocean Energy Management (BOEM) to fund the survey. NOAA, the Navy, and BOEM need HICEAS data to update abundance estimates in order to sustainably manage cetacean populations in Hawaii and mitigate impacts from human activities. Thanks to everyone who came together to complete HICEAS 2017! — Erin Oleson, Cetacean Research Program Lead

Q: Why do you only research the Pacific Islands? — Elyse (Honolulu, HI)

A: NOAA Fisheries is responsible for conducting research throughout all marine waters of the United States. This research is conducted by various NOAA Fisheries Science Centers around the country, each with their own geographic area of focus. The Northeast and Southeast Fisheries Science Centers on the East Coast conduct research in the U.S. Atlantic Ocean, Gulf of Mexico, and Caribbean Sea. Here at the Pacific Islands Fisheries Science Center, we primarily work in—you guessed it—U.S. waters of the Pacific Islands. Next year, the Southwest Fisheries Science Center (based in California) is conducting a survey off the U.S. West Coast that's similar to HICEAS, called California Current Cetacean and Ecosystem Assessment Survey. — Jeff Moore, California Current Marine Mammal Assessment Program Lead

Q: Do any of the people participating in HICEAS have sea sickness but still participate in this program? — Jessica (Honolulu, HI)

A: Yes, sea sickness in some form is actually more common than you might think, even among cetacean researchers and others who may spend a lot of time on the water. Sea sickness doesn't always mean "feeding the fishes" (vomiting)—it can also take the form of fatigue, dizziness, or mild nausea. We get sea sick when there is a disagreement between the motion we are seeing and the motion that our vestibular (or balance) system is sensing. Our susceptibility to sea sickness can depend on many factors, including our health and behavior and the surrounding conditions of the sea. While some people are certainly more susceptible to sea sickness than others, most people will experience it in extreme conditions. Personally, I have found that, as I've gotten older, I get sea sick more often, especially on small boats, but also occasionally on the ship. Fortunately, there are many natural and medicinal remedies we can take to treat sea sickness, and there are a variety of actions that we can take to help; for example, taking a nap or looking ahead on the horizon. Fortunately, over a few continuous days at sea, our bodies generally adjust to the motion, allowing us to feel normal again... unless the seas suddenly take a turn for the worse! — Amanda Bradford, Research Ecologist

Q: What is CTD that is used to collect the oceanic information? — Brigette (Honolulu, HI)

A: CTD stands for conductivity, temperature, and depth. A CTD is a set of electronic instruments that we lower into the water from the ship in order to measure the salinity, temperature, depth, and concentration of particles in the water column. Using these measurements we can study how the physical characteristics of the ocean relate to the distribution of cetaceans. The CTD is usually attached to a cylindrical metal frame that also has a set of water bottles (called a "rosette") which collects water samples at different depths. During HICEAS, researchers collected water samples at Cross Seamount for an eDNA (environmental DNA) study of beaked whales. — Marie Hill, Senior Cetacean Specialist

Q: What is one of the main birds that you study? — Miranda (Honolulu, HI)

A: Thank you for your bird question. In this large-scale ecosystem-based study, we're focusing on all seabirds. Contrary to what many people may think, there are many different kinds of seabirds that spend their lives on the open ocean. They are highly specialized birds, able to drink seawater, and capable of extraordinary energy-efficient gliding flight, taking advantage of the constant wind blowing across the sea. We've seen at least 40 different kinds of seabirds; some familiar, such as albatrosses, and others more obscure, such as various kinds of petrels, shearwaters, and storm-petrels. We know where most of these birds go to lay eggs and raise their chicks, but once they leave for the big blue sea, their destination and routes are a mystery. Surveys such as this help to fill in the gaps about what we know and don't know about these enigmatic and endearing birds of the sea. — Michael Force, Seabird Observer

Q: Do animals migrate from one island to another island? — Lauren (Honolulu, HI)

A: Photo-identification and satellite tag data have shown that many of the cetacean species that live in Hawaiian waters travel between the islands. Because their prey are mobile and will shift locations to more productive waters, whales and dolphins must move around to feed. As well, whales and dolphins must sometimes travel between locations to find mates. Some species, like humpback whales, even travel over 1,000 miles between Alaska (where they feed in the summertime) and Hawaiʻi (where they mate and calve in the winter time). — Marie Hill, Senior Cetacean Specialist

Q: What inspired you to do this job and what was the process of getting to this point? — Melissa (Honolulu, HI)

A: It's funny—I had really enjoyed my first field work on cetaceans, working with humpbacks off Silver Bank, Dominican Republic. And I told myself that when I didn't find that next cetacean job, when all the opportunities to work out in the field didn't appear, I would find another line of work. But somehow I always did find that next job, that next field project, that next opportunity. I think in a lot of ways I was lucky in that I met people in charge of projects who happened to need help in the field. But also the cetacean community is very close-knit. So if you work hard, get along with the other people on your team, learn as much as you can and be helpful and useful AND have a bit of luck, opportunities will arise. It's up to you to decide if you are going to make the most of your chances. It involves a lot of hard work, some smarts and again, a bit of luck.  Suzanne Yin, Marine Mammal Observer

Q: If you don't have much knowledge about climate change, how can you still contribute in making Earth better? — Meenakshi (Honolulu, HI)

A: One of the biggest problems involved with climate change is the amount of carbon dioxide (CO2) in the environment. You can reduce how much CO2 you contribute, or your "carbon footprint," by doing things like growing your own fruits and vegetables in a garden, or even in a couple of pots on your lanai. Or buy food from a local farmer's market. The more food grown in Hawaiʻi, the less would have to be shipped here using fuel, which when burned releases CO2 into the air. You can also walk or ride your bike places instead of taking a car, which also burns fuel. Recycle as much as possible—buy food in recyclable packaging. Recycle your cans, plastics, and bottles. Turn off the lights when you're not in the room, and unplug your chargers when you're not using them. These may all seem like little things, but they can all add up to help save energy (which reduces the amount of fuel burned) over time! — Andrea Bendlin, Marine Mammal Observer

Q: Can different species of dolphins have offspring together? Has it ever happened before? — Claire (Honolulu, HI)

A: Yes they can! But as far as we know, it is rare. Normally animals from different species do not interbreed, but if they do, their offspring is infertile. However, there are a few interesting cases of interbreeding in marine mammals. Keikaimalu is the daughter of a bottlenose dolphin and a false killer whale; she lives at Sea Life Park and has given birth to three calves. Also the Clymene dolphin seems like it may be a hybrid between striped and spinner dolphins. There are also cases of hybrids in baleen whales. — Siri Hakala, Protected Species Biologist

Q: What would a middle school student need to study to become an oceanographer? — Puanani (Waiʻanae, HI)

A: Great question! There are several areas of study within the broad topic of oceanography or marine science. True oceanographers study the physics, geology, and chemistry of the ocean itself. Marine biologists study the life within the oceans. Fisheries scientists focus even more specifically on fishes or other ocean species important as food and commercial resources for humans. The specialized study required for becoming a professional marine scientist usually comes in college. However, as a middle school and high school student, you can start preparing for a marine science pathway by studying hard in your general science (biology, chemistry, physics), math, and computer classes. Also, if you can, spend some time getting acquainted with the ocean — visit aquariums, or if you live near the coast, wander around the tide pools and beaches. Go snorkeling. Maybe even learn to SCUBA dive. All this will help you to become familiar with some of the ocean’s wonders, which will pique your interest and passion in the subject and maybe even help you get your first job. It doesn’t hurt to start learning your way around a boat, too! — Jeff Moore, California Current Marine Mammal Assessment Program Lead

Q: With the acoustic team able to make more positive identifications through the use of hydrophones, how can the team know for sure which sound bite belongs to which animal? — Wilson (Mukilteo, WA)

A: NOAA and other researchers around the world have published information about the sounds cetaceans produce. Based on the scientific literature, we have set up our acoustic recording and tracking systems to help identify the species we encounter. When we acoustically detect cetaceans, we often visually confirm which species we've found. We can then compare those records with unknown acoustic recordings, such as those recorded at night. — Jennifer Keating, Passive Acoustic Technician

Q: What's a typical day like for you? What are the most enjoyable, and the most challenging, parts of each day? — Meredith (San Diego, CA)

A: During a typical day, we stand multiple-hour shifts on the highest deck of the ship looking through very high-powered binoculars (or "big eyes," as the scientists lovingly call them). We search and scan the waters for any signs of marine mammals (a dorsal fin, a part of an animal's back, etc.). If we catch a glimpse of a whale or dolphin, we document the species, direction they are traveling, and number of individuals that are present (including calves and newborns)! If we are very lucky and weather permits, we will launch a smaller boat to approach the group to gain a more up close and personal perspective, in order to obtain photos of the animals. The most enjoyable part of the day is getting to witness the sunrise and sunset over the rolling seas. It is a beautiful sight to watch the sun emerge each morning and then sink back into the waves again at night. Each one is different, and breathtakingly gorgeous in its own way! — Heather Colley, Marine Mammal Observer

Q: Do whales sleep? Do different species hang out together? — Star (Haleʻiwa, HI)

A: Whales and dolphins do sleep, but they do so in a way that is very different from most other mammals, including humans. Instead of the extremely low levels of muscular activity, voluntary behavior, and consciousness that most mammals experience when they go to sleep, whales and dolphins maintain the ability to swim, breathe, and remain aware in their ocean environment. They do this by only sleeping with one hemisphere (side) of their brain at a time. This state is called unihemispheric sleep and means that they can actually sleep with one eye open!

Different species of whales and dolphins regularly hang out together, which may provide increased foraging and social opportunities, as well as protection from predators, for one or both of the associating species. Whales and dolphins that are commonly found in the company of other species include short-finned pilot whales, rough-toothed dolphins, and bottlenose dolphins.  Amanda Bradford, Research Ecologist

Q: Can you provide a technical explanation for how you localize underwater critters based on sound? I would expect the acoustic sensors on the towed line to roll around thus causing their orientations to change over time. How precisely can you localize the sea life? — Jeff (Bellevue, WA)

A: We are able to localize sounds heard on a towed hydrophone array using the time the sound arrives at each of the individual hydrophones. Within the array, the hydrophones are fixed in position so that their distance from one another can be accurately measured, and while the array itself may roll, the hydrophones are omni-directional—they sense sound with the same amplitude from all directions. When a sound is detected, the time of that sound's initial arrival at each individual hydrophone is measured, and the differences between those arrival times together provide a bearing to the sound source. For example, if the sound is ahead of the ship, the sound will arrive first at the hydrophone closest to the ship, then sequentially at those further away. As the ship moves forward towing the array, and more sounds from the same source are heard, the angle to the sound will change, eventually overlapping at the source's location. — Erin Oleson, Cetacean Research Program Lead

Q: Do the whales have names? Who gets to pick the whale names and how are they chosen? — Gideon (Seattle, WA)

A: Well, that depends a bit on the species of whale. But in general, there are too many whales for researchers to give them all names. Occasionally, when we see the same whale repeatedly over many years, we will give them a name. Usually, the researchers who study that whale will choose the name based on a distinctive feature on their body. For many whales, this is a color pattern on the side of their body or underside of their tail, but in the case of "Spike," a humpback whale regularly seen in the waters off Maui, his name comes from the unique spike-like protrusion just forward of his dorsal fin. — Andrea Bendlin, Marine Mammal Observer

Q: How can you possibly count ALL of the dolphins when they are mostly underwater? — Brie (Mānoa, HI)

A: For each group of dolphins we encounter, accounting for all individuals is mostly a matter of counting, counting, and re-counting animals when they surface to breathe, paying attention to where they are in relation to each other and how much time passes between surfacings. In larger groups, dolphins often cluster into smaller sub-groups, which are easier to count and then add together to get a full group size estimate. After watching multiple surfacings and making several separate counts, we start to get a good sense of how many animals are present. Then we express our multiple counts as a range—from the minimum to the maximum number of animals we're certain are present in the group—in addition to a best count. — Allan Ligon, Marine Mammal Observer

Q: How many people are on the ship, and what are their roles? — Brandon (Ballard, WA)

A: For each HICEAS leg, each NOAA ship has approximately 35-40 people aboard, including 20-25 ship's personnel and 13-15 scientists. The ship's personnel consist of 5-6 NOAA Corps officers, who oversee operations and drive the ship, and 15 or more crew members with specific roles: deckhands, engineers, cooks, a medical officer, and specialized technicians. The science party includes a cruise leader, who works with the ship's officers to keep the project on track, six marine mammal observers, two seabird observers, three acousticians, and one to three visiting scientists. While collecting scientific data is the main function of the ship, everyone on board plays an important role in making sure that happens safely and effectively. — Kym Yano, HICEAS Coordinator

Q: What do killer whales eat? — Jack (Waipiʻo, HI)

A: Just like humans around the world, different populations of killer whales eat different things. Some groups are extremely picky eaters, while others are more opportunistic. Along the west coast of North America, there are separate groups of killer whales that specialize on either salmon, marine mammals (seals, sea lions, porpoises, and even large whales), or sharks. In the North Atlantic, some killer whales specialize on herring or mackerel, but some also eat seals or tuna depending on location and time of year. In Antarctica, there are separate groups that specialize on minke whales, seals, penguins, or fish. Not much is known about the diet of killer whales that occur in Hawaiian waters, but they have been observed eating marine mammals, cephalopods (squid and octopus), and sharks. — Adam Ü, Cetacean Observer

Q: How many calves can a momma whale have in her lifetime? Do momma whales have twins? — Jen (Waipiʻo, HI)

A: The number of calves a female whale or dolphin will have in her lifetime varies by species and depends on the age she starts having calves, how often she has them, and the age she stops having them. For example, baleen whales like the humpback whale may start having calves between the ages of five and 10, and may have a calf as often as every other year throughout their lives, which may span 60-80 years or more. On the other hand, small dolphins like the pantropical spotted dolphin may not start having calves until around 10 years of age, may go two or more years between calves, and only live about 40 years. Some dolphin species, like the killer whale and other 'blackfish,' will go five or more years between calves and stop having calves around age 40, even though they can live much longer (similar to female humans). What is common to all whale and dolphin females is that they almost always give birth to one calf at a time. While there is rare evidence that whales and dolphins can be pregnant with twins, it is unlikely that more than one calf would survive after birth. — Amanda Bradford, Research Ecologist

Q: What are the most common marine mammals you see around the Hawaiian Islands? Are they more abundant in any particular area? — Amber (Pearl City, HI)

A: The most common marine mammals seen around the Hawaiian Islands are cetaceans (whales and dolphins). There are 25 species known to occur within Hawaiian waters. While rough-toothed, striped, and other small dolphins are the most abundant species farther from shore, some cetacean species are seen more frequently than others because of their close proximity to land. Spinner dolphins are often found close to shore around the main islands, where they come to rest during the day after feeding at night in deeper waters. Thousands of humpback whales come to Hawaiian waters each winter to mate and give birth to their calves. They prefer shallow water when they are in the wintering area, so they are often seen relatively close to shore off the Hawaiian Islands. A large number of these whales are found around the islands of Maui, Lānaʻi, and Molokaʻi. — Marie Hill, Senior Cetacean Specialist

Q: Why are the HICEAS conducted every 8 years? Why aren't they done more often? — Clark (San Francisco, CA)

A: Significant resources are required to adequately survey the HICEAS study area, which—at 1.8 million square nautical miles—is larger than the combined areas of Alaska and Texas, the two largest U.S. states. Specifically, HICEAS needs two NOAA ships, almost 200 days at sea, and a large team of skilled scientists, and that's just for the cruise itself. We put a lot of time into planning the survey prior to setting sail and then estimating species abundance and conducting other analyses after the cruise is over. We have to balance the requirements of HICEAS with the resources we have available, as well as other research priorities in Hawaiian waters and other parts of the Pacific Islands Region. However, we do consider abundance estimates to be outdated after eight years, so at a minimum, HICEAS will be conducted every eight years. So far, there has been a HICEAS in 2002, 2010, and now 2017. — Amanda Bradford, Research Ecologist

Q: Why are big ships needed to look for whales and dolphins? Why can't we use helicopters? — Tammy (Haleʻiwa, HI)

A: The answer is range. The goal of a 'population assessment' survey like HICEAS is to estimate how many whales and dolphins there are of each species in the United States' jurisdictional waters around all of the Hawaiian Islands. The survey area extends to 200 nautical miles offshore, from east of the Big Island all the way west to 200 nautical miles beyond Kure Atoll. A big ship can reach all of those places, but a helicopter cannot. — Paula Olson, Marine Mammal Biologist

Q: Why is it important to estimate the abundance of cetaceans? — Rachel (Sacramento, CA)

A: All marine mammals in the United States are protected by the Marine Mammal Protection Act, which was written to prevent marine mammal populations from becoming too small to recover from human and other impacts. To support this goal, we must gather information, like where the population is distributed and how much it is affected by humans, so that we can determine how it is doing. An important piece of information is population size, or how many animals are in the population. If we do not know how many whales or dolphins there are, we will not know how to help keep their populations healthy and sustainable. — Amanda Bradford, Research Ecologist

Q: How can you hear the dolphins underwater? — Lucy (Honolulu, HI)

A: In order to hear dolphins underwater we use special underwater microphones called "hydrophones." These hydrophones allow scientists to hear the sounds that dolphins use to communicate. There are three possible types of sounds to hear from a dolphin: clicks, burst pulses, and whistles. Clicks sound like the noise you make when you snap your fingers. Burst pulses can sound like a "raspberry"; the noise you make when you press your lips on your arm and blow air. Whistles sound just like you and me trying to whistle! — Jennifer Keating, Passive Acoustic Technician

Last updated by Pacific Islands Fisheries Science Center on August 27, 2018