From the ground up: forming an unmanned aircraft system (UAS) program to study whales and dolphins in the Pacific Islands

By Amanda Bradford, Marie Hill, and Kym Yano
PIFSC Cetacean Research Program

Once used mostly for military purposes, unmanned aircraft systems (UASs, aka drones) are becoming increasingly popular in a wide range of civilian activities.  It’s hard to go outside these days without seeing a recreational drone in the air, especially here on the beaches of O’ahu.  An aerial view often offers a unique and useful perspective of a particular subject, which a UAS can provide with less of a financial and human investment than a manned aircraft.  The use of UAS technology to study wildlife, including cetaceans (whales and dolphins), is spreading rapidly, with the added bonus that a UAS can be less disruptive to animals than other research methods.

The PIFSC Cetacean Research Program (CRP) is tasked with providing scientific information to support the conservation of cetacean populations in the Pacific Islands.  Specifically, we estimate the sizes of these populations, determine where they spend their time, and evaluate human-caused threats that may be affecting them.  We are ultimately interested in the health of the populations and the individuals within them.  To accomplish our research goals, we use a number of methods, including photo-identification, biopsy sampling, satellite tagging, and acoustic monitoring.  Embracing the wave of UAS technology, we were very excited to add aerial photography to our toolkit because taking vertical photographs from the air gives us a way to directly investigate the health of populations and individuals.  For example, we can keep track of how many females in a population are having calves and measure the body condition of individual whales and dolphins.

However, there was only one problem.  No one in the CRP had a background in cetacean aerial photography or even knew how to fly a drone.  We were, literally, starting from ground zero.


Learning to fly a UAS over whales did not begin on the open ocean, but instead in a grassy field. Photo credit: NOAA Fisheries/Amanda Bradford

In the spring of 2017, we began the process of becoming UAS trained and certified, following through with both Federal Aviation Administration (FAA) and NOAA requirements.  We focused on working with the APH-22 hexacopter, an approved NOAA platform that has been used by other biologists to successfully collect vertical aerial photographs of cetaceans and other marine mammals.  We completed all our basic requirements and some initial training work just in time for the Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS), which took place from July to December of 2017.  We were prepared to add hexacopter operations to our suite of research activities; however, we need calm weather conditions (winds less than 10 knots) to collect usable photos from the hexacopter.  These types of weather conditions are rare in the exposed offshore waters of the Hawaiian Islands.  Given few breaks from the prevailing trade winds, we only made a total of 12 flights over cetaceans (spinner dolphins and short-finned pilot whales) on 3 days during HICEAS.


Short-finned pilot whales, including a couple of mother-calf pairs, encountered 175 nautical miles north of Kauai during HICEAS. Photo credit: NOAA Fisheries/Rory Driskell and Amanda Bradford

We were disappointed not only because we didn’t collect very much UAS data during HICEAS, but also because we didn’t have more opportunities to fly the hexacopter.  Operating a UAS from a small boat that is rocking around with the large swell of the open ocean, while trying to find the best position to hover over fast-moving animals, is not easy.  And we wanted to become good at it, so as to make the most of future opportunities to collect aerial photos of cetaceans.

We agreed that we needed to improve our UAS skills, so we organized a week-long training project off the leeward coast of O’ahu.  Leeward O’ahu generally offers protection from the prevailing winds and is regularly used by cetaceans, especially spinner dolphins and, in winter, humpback whales.  Our goal with this project was to fine-tune our UAS data collection protocols so that we could gain a better understanding of the factors that produce the highest quality images for evaluating the size and age composition of cetacean groups and the size and body condition of individuals.  For example, what are the best camera settings and permitted altitudes for certain species and situations?  When is the best time to launch the hexacopter and conserve battery life when individuals in a group are not spending much time at the surface?  We were not focused on a particular research question or species, but rather on the UAS operation itself.


Retrieving the hexacopter after a flight over a pair of humpback whales off leeward O’ahu. The unpredictable behavior of the whales at the surface made flying over them surprisingly difficult! Photo credit: NOAA Fisheries/Kym Yano


A bird’s eye view of the UAS team working off leeward O’ahu. Photo credit: NOAA Fisheries/Kym Yano and Marie Hill.

For this project, we conducted daily small-boat surveys off leeward O’ahu between January 8 and January 12, 2018, covering the coastline between Ko Olina in the south and Kaena Point in the north.  Cetaceans that we sighted were only approached (and considered “encountered”) if they were outside of restricted airspace and not in the presence of tour operators.  Overall, we encountered 12 cetacean groups of 3 species (false killer whales, humpback whales, and spinner dolphins).  We considered the potential to fly the hexacopter over each of these groups, which involved evaluating the weather conditions, the behavior of the animals, and the proximity of the group to other vessels.  In total, we made 8 flights over 5 groups of 2 species (humpback whales and spinner dolphins).


A large group of spinner dolphins encountered near Kaena Point. A series of such images as the group passes under the hexacopter will allow us to determine the size and age composition of the group. Photo credit: NOAA Fisheries/Marie Hill and Amanda Bradford

We made 5 additional flights not over cetaceans for the purposes of testing camera settings and taking calibration images, where we photograph an object of known size (a 10-foot section of PVC pipe) so that we can determine the amount of error in our cetacean size estimates. In total, 13 flights were made during the week.  These flights ranged from 4.2 to 13.8 minutes and totaled 1.9 hours in duration.  While our focus was on aerial photography, we did use our hand-held cameras to take photo-identification images during two encounters: 1) a group of false killer whales from the endangered main Hawaiian Islands population that was too spread out and moving too quickly to fly over, and 2) a group of spinner dolphins that we encountered during a period when the wind speed was too high for UAS operations.


A map showing our cetacean UAS pilot study effort and encounters off leeward O’ahu from January 8 to January 12, 2018. We made a total of 13 UAS flights, with 8 of them made over 5 cetacean groups (shown with a colored border around the map marker).

Now that our week-long UAS training project is over, are we UAS pros certain that we’ll get top-notch images every time we fly the hexacopter over cetaceans?  Unfortunately, no.  In fact, you’d laugh if you saw our humpback whale photos, which were difficult to take because the whales had long dive times and short bouts at the surface.  This effort continued to show us that each species, group, and situation is different and that we still have a lot to learn.  On a positive note, we made significant progress and are more confident that we can use UAS as a platform to collect meaningful data on cetaceans throughout the Pacific Islands.  And, for that reason, we are flying high.

All photos taken under research permit.  We’d like to acknowledge the Ko Olina Marina and Ko Olina Community Association for logistical support during the leeward O’ahu UAS training project.  Special thanks to Jenna Morris of Dolphin Excursions for alerting us to the presence of main Hawaiian Island false killer whales in the study area.

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That’s a Wrap: HICEAS 2017 is Complete!

By Karin Forney
HICEAS Cruise Leader

In our last update on the progress of the Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS), the NOAA Ship Reuben Lasker had finished three of its four survey legs. In this, our final installment of the HICEAS 2017 blog series, I report on the fourth and final survey leg of the Lasker, which marks the end of HICEAS 2017. After a six-day in-port, the Lasker departed Honolulu with 14 members in the science team. Our goal for Leg 4 was to survey as many of the remaining transect lines in the eastern portion of the study area as possible, and then complete a 10-day transit back to the home port of the Lasker in San Diego, CA (from Hawaii to San Diego at the speed of a bicycle).

Lasker Leg 4 science team just before departing Honolulu on November 15, 2017. From left to right: Bernardo Alps (Cetacean Observer), Juan Carlos Salinas (Lead Cetacean Observer), Charlotte Boyd (Cetacean Observer), Michael Richlen (Visiting Scientist), Karin Forney (Cruise Leader), Jennifer Keating (Acoustician), Heather Colley (Cetacean Observer), Jessica Crance (Acoustician), Shannon Coates (Lead Acoustician), Suzanne Yin (Lead Cetacean Observer), Michael Force (Seabird Observer), Andy Bankert (Seabird Observer), and Mark Cotter (Cetacean Observer). Photo credit: NOAA Fisheries/Amanda Bradford

Although swells and winds were challenging, we successfully conducted visual line-transect and acoustic towed array surveys of cetaceans (whales and dolphins) along almost all of the remaining transect lines north of the main Hawaiian Islands. We also continued other operations, including conductivity, temperature, and depth (CTD) sampling, sonobuoy stations, and a strip transect survey for seabirds. However, our leg was unexpectedly cut short on November 30th when, only hours from completing our final study-area transect and beginning the long transit home, the ship was instructed to return to port in Honolulu instead of San Diego.

We found ourselves back in Honolulu on December 1st, where we packed up all our gear and ended the project nine days earlier than expected. Our shortened leg was nonetheless a success, finishing nearly 890 nautical miles of transect lines and yielding 32 sightings of at least 10 cetacean species. The acoustics team detected 98 cetaceans representing at least 13 species. Minke whales, with their infamous “boing” vocalizations, were heard most frequently and became a near-daily presence (minke whale soup). The acousticians also heard sei whales for the first time during HICEAS 2017 as a result of a sonobuoy deployment. The seabird observers saw 921 seabirds representing at least 27 species during their strip transect effort and counted 2,960 seabirds of at least 15 species in 22 feeding flocks. Three of the feeding flocks were associated with cetaceans, including false killer whales, spotted dolphins, and dolphins that were not identified to species.

Daytime survey effort (white lines) and cetacean sightings (see legend) made within the Hawaiian EEZ (blue line) during HICEAS 2017 Leg 4 aboard the Reuben Lasker. The red shading is a focus area around the main Hawaiian Islands, and the green shading is the Papahānaumokuākea Marine National Monument, with darker shading where the Monument was expanded in 2016

As during previous HICEAS legs, we had multiple false killer whale detections and implemented the two-phase Pseudorca Protocol. We had four successful passes in “Phase 1” (where we localized subgroups along the transect using acoustic and visual methods, which can stretch on for many, many miles!) and one successful “Phase 2” (where we turned back and approached as many subgroups as possible to get better estimates of subgroup sizes). We were able to launch the small boat on one of the false killer whale sightings and obtain many photos and three biopsy samples.

Woo-hoo, false killer whales, our highest priority species! Photo credit: NOAA Fisheries/Charlotte Boyd

Another highlight of the leg was a group of two fin whales, which we initially detected visually. After deploying a sonobuoy near the sighting, we immediately started getting the classic 20 hertz pulses in the general direction of the whale. We dropped another sonobuoy when the visual team had a re-sighting, and were able to localize both whales­–this was the first time during HICEAS that we matched visual and acoustic detection angles in this way. The animals were traveling slowly, so we spent some time obtaining fabulous photos and making a few biopsy attempts from the Lasker.

A fin whale, a rare sight in Hawaiian waters. Photo credit: NOAA Fisheries/Mark Cotter

Our final noteworthy event was just after we broke off our final transect on November 30th to return to Honolulu. Moments later, we suddenly found ourselves in a crazy burst of activity on both the flying bridge and in the acoustics lab–­a confusing mess of sperm whales, Longman’s beaked whales, and short-finned pilot whales, with a fin whale thrown in for good measure. The acoustics team furiously recorded all the vocalization details reflected on their busy computer screens, and the visual team scrambled to sort out what-species-was-where ahead of the ship. Unfortunately, none of the animals came close enough for great photos, but it was a memorable moment for sure, illustrating that things are often “boom-or-bust” out here in the marine realm, especially in the waters far offshore of the Hawaiian Islands.

Well, after 179 days at sea, 345 sightings and 766 acoustic detections of at least 23 cetacean species (21 inside the Hawaiʻi study area), and several thousand sightings of at least 45 species of seabirds, HICEAS 2017 is complete! Considered collectively, the cetacean sightings illustrate the boom-or-bust pattern in the study area quite nicely (see map below). Some survey transects had no sightings at all, and some had many groups of different species. This result underscores the­–often hidden–­features of our ocean ecosystems that determine species distribution and abundance.

Daytime survey effort (white lines) and cetacean sightings (see legend) made within the Hawaiian EEZ (blue line) during HICEAS 2017 aboard the Oscar Elton Sette (three legs) and Reuben Lasker (four legs). The red shading is a focus area around the main Hawaiian Islands, and the green shading is the Papahānaumokuākea Marine National Monument, with darker shading where the Monument was expanded in 2016.

Now, the analysis effort begins. Over the next several months, we’ll be working to derive new abundance estimates for the cetacean species we detected. There likely won’t be another HICEAS of this scale for several years. HICEAS 2017 was a gargantuan effort, and in the end, a huge success. We sincerely thank all the amazing scientists who collected high-quality visual, acoustic, and oceanographic data, as well the officers and crew of the NOAA Ships Oscar Elton Sette and Reuben Lasker­–we could not have done it without you!

The sun may have set on HICEAS 2017, but the invaluable data and memories will shine for years to come. Photo credit: NOAA Fisheries/Bernardo Alps

All photos taken under research permit.

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HICEAS Hilite: False killer whales, they’re just going through a phase

By Erin Oleson and Amanda Bradford
HICEAS Chief Scientist and HICEAS Cruise Leader

One of the primary goals for a ship-based survey like the Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS) is to collect the data we need to estimate abundance (population size) for each cetacean (whale or dolphin) species found in Hawaiian waters. To that end, each time we sight a cetacean group, we promptly divert the ship toward the group in order to confirm what species we’ve encountered and to count the number of individuals in the group. Once we have the basic data we need for abundance estimation, we often take identification photos and collect small tissue samples to better understand the range, structure, and health of the population. We follow this protocol every day with every group of each species we find… with the exception of the false killer whale (Pseudorca crassidens), who require a different approach to data collection.

In a burst of speed, a false killer whale slices the water surface. Photo credit: NOAA Fisheries/Bernardo Alps

False killer whales are highly social and often hunt large pelagic fish (e.g., tunas, mahi-mahi, and billfishes). Research on false killer whales in the main Hawaiian Islands has revealed the tendency of these whales to associate in small coordinated subgroups that can span tens of miles. These smaller subgroups of false killer whales coordinate to search for prey across a broader area and then come together as a group to share their catch. The larger groups often consist of animals that are related or that have been associated with each other for many years–perhaps like your family and the friends in your neighborhood. However, this tendency of false killer whales to occur in small subgroups spread out over a large area meant our survey team had to change the way we work with false killer whale groups when they are encountered, so that the data we collect are better suited for estimating abundance.  Instead of treating each group as the detection unit like we do for all other species, we focus instead on the subgroups, using a very specific protocol to get the data we need in the least biased way possible. We call it the Pseudorca Protocol–a name innocuous enough on paper, but one that seems to increase the blood pressure of every person on the ship once it is uttered.  This two-phased protocol tests the will and comradery of the science team, temporarily pitting the cetacean observers and acousticians against each other, and requires patience from the ship’s personnel, who must maintain their operations against a backdrop of nerve-wracking data collection.

False killer whales evolved to use subgroups to maximize their feeding success; false killer whale researchers evolved to use the Pseudorca Protocol to maximize their data collection success. Photo credit: NOAA Fisheries/Mark Cotter

When we see a false killer whale, rather than diverting the ship to assess the group like we would for all other species, we remain on our survey transect (or trackline), recording the position of each subgroup as we pass by. We call this “Phase 1” of the Pseudorca Protocol. We learned from previous surveys that turning toward the first subgroup we see in an attempt to count all individuals in the entire group creates a bias in our data set. That is, false killer whale subgroups are generally separated by large enough distances that the group itself does not conform to the theoretical framework of line-transect sampling, the method we use to estimate abundance. The line-transect method treats aggregations of animals as if they occupy a single point (defined as the center of the grouping) off the trackline. It works by allowing us to use the sightings we made within a certain distance (in our case, three nautical miles) of the trackline as a basis for estimating the abundance of that species in the entire study area. If we venture miles from our trackline counting individuals that were not among those we initially saw, then we are essentially double-counting those animals. To counteract this bias, we remain on the trackline during Phase 1, with the visual and acoustics teams working independently to detect false killer whale subgroups. More often than not, the acoustic team hears false killer whales before the visual team sees them. This could be due to the distance of each subgroup, challenging viewing conditions, sneaky behavior of the animals, or all of the above. In these cases, the observers don’t even know that Phase 1 has begun, as the acousticians are not allowed to tell the observers because doing so would risk influencing their sighting process.

Acoustic detections of false killer whale subgroups during Phase 1 of the Pseudorca Protocol that took place on September 12, 2017, off the south side of Kauaʻi. This Phase 1 lasted two hours and spanned 19.3 nautical miles of trackline, resulting in 19 acoustic and 18 visual detections of false killer whale subgroups. Acoustic detections of successive subgroups are separated by color and shown on both sides of the ship’s trackline because we can’t differentiate left or right with our linear towed hydrophone array. Error bars at the end of each subgroup localization show the confidence in the location. The first violet and last orange locations are very uncertain, but the remaining 17 localizations are very accurate. Image prepared by Jennifer Keating.

Phase 1 of the Pseudorca Protocol ends when the ship has passed through all the false killer whale subgroups along the trackline. The ship then turns back around and is directed by the acoustics team through the highest concentration of subgroups so that the cetacean observers can get a better count of the number of individuals in as many subgroups as possible. We call this “Phase 2” of the Pseudorca protocol. The drawback of Phase 1 is that because we are in ‘passing mode,’ when the ship does not leave the trackline for sightings, we are not able to focus on getting counts of subgroup size, which is an important parameter in the abundance estimation process. Sometimes, though, we are still able to get good subgroup size counts during Phase 1; for example, when a subgroup is close to the trackline or when an observer watches a subgroup for multiple surfacings. However, having a phase dedicated to obtaining subgroup sizes without the constraint of staying on the trackline gives us an opportunity to increase our sample of counts and to better understand the behavior of the subgroups and, potentially, the group as a whole. Once both phases of the Pseudorca Protocol are complete, we then approach false killer whales as we would most other species, collecting identification photos, tissue samples, and even deploying satellite tags to track the movements of individuals.

If only false killer whales would follow the Pseudorca protocol! Photo credit: NOAA Fisheries/Charlotte Boyd

One protocol, two phases–sounds straightforward enough, right? What’s the big deal, and why all the stress? Well, first of all, when we sight false killer whales, all available hands are called to the ship’s flying bridge. In addition to the three cetacean observers on effort at any given time, the three other observers on the visual team must abruptly end their break time to serve as back-up observers, making counts of sighted subgroups during Phase 1 and helping to search for subgroups during Phase 2. The Pseudorca Protocol can go on for hours. During Phase 1, the acousticians wait in suspense for the observers to make a subgroup sighting, hoping that the visual team won’t sight another species in the meantime and ask the ship to turn, a request that must be awkwardly declined. However, Phase 2 is usually the more frustrating phase, as it often seems that once we turn around to relocate the subgroups, the whales either get playful or go quiet, behaviors that make it difficult for both teams to keep track of how many subgroups there are and how many individuals are in each. Further, call us paranoid, but we can’t help thinking that false killer whales are trying to mess with us. They always seem to show up during meals or just before sunset. They can taunt the acoustics team with their eerie whistles for miles upon miles and never show themselves at the surface. They can torment the visual team by joining and leaving subgroups or by mixing with other species. They never do the same thing twice. We are convinced that they are on to us.

Scientists aboard the NOAA Ship Oscar Elton Sette (in the background) wait anxiously while these false killer whales plot their next move. Photo credit: NOAA Fisheries/Adam Ü

Why do we put so much effort into the data collection of this challenging species? There are three populations of false killer whales in Hawaiian waters. Obtaining accurate and precise abundance estimates is necessary for the conservation and management of these populations. The main Hawaiian Islands insular population is relatively small, numbering around 200 individuals, with a range limited to within about 50–75 nautical miles of the main Hawaiian Islands. The population is listed as endangered under the U.S. Endangered Species Act because of historic declines in population size and its current small size. There is another island-associated population around the Northwestern Hawaiian Islands that we know very little about.

The Hawaiʻi pelagic population is broadly distributed throughout Hawaiian waters and beyond, likely moving across broad areas following their prey. The large pelagic fish they are after are also the targets of the Hawaiʻi-based longline fisheries. False killer whales have learned to take fish from longlines, a behavior known as depredation. In the process of stealing fish from hooks, the whales sometimes end up hooked or entangled in the gear themselves. Unfortunately, these gear interactions happen enough that NOAA Fisheries had to assemble a Take Reduction Team to develop measures to reduce the bycatch of false killer whales. One of these measures defines an area that can be closed to fishing when pelagic false killer whale bycatch exceeds a threshold determined by the current abundance estimate. An imprecise abundance estimate will lower this threshold. For each of the populations, we need an accurate abundance estimate to determine if the population is healthy and sustainable. As difficult as it is, we will persevere with the Pseudorca Protocol!

This map of the Hawaiian Islands shows all of the HICEAS 2017 survey effort (white lines), with false killer whale sightings shown as violet circles. The red shading is a focus area around the main Hawaiian Islands, and the green shading is the Papahānaumokuākea Marine National Monument, with darker shading where the Monument was expanded in 2016.

This post is the last in our HICEAS Hilite series. We hope you enjoyed these features of some of the cetacean species we are lucky enough to see in Hawaiian waters. HICEAS 2017 officially ended on December 1st, and we have one remaining blog to post on this massive, five-month effort, so stay tuned to the HICEAS website for this and other final updates!

All photos taken under research permit.

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HICEAS Hilite: [Dolphin] Dinosaurs Still Exist

By Shannon Coates and Mark Cotter
HICEAS Lead Acoustician and HICEAS Cetacean Observer

With the the Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS) of 2017 winding down, we were approached by our Cruise Leaders about writing a blog about the rough-toothed dolphin (Steno bredanensis). It’s kind of funny that we were asked to write a blog about this species, because unbeknownst to our Cruise Leaders, the rough-toothed dolphin is one of our favorite cetaceans (whales and dolphins). Not only do rough-toothed dolphins have a distinct reptilian appearance that conjures thoughts of a prehistoric animal (at least in our opinion), they also happen to be one of the smartest dolphins in the ocean. As a result, rough-toothed dolphins are one of the more easily distinguishable dolphin species and demonstrate unique and interesting behaviors.

With their gently sloping heads and large bulging eyes, we think rough-toothed dolphins look somewhat reptilian and prehistoric – a dolphin dinosaur, if you will. What do you think? Photo credit: NOAA Fisheries/Marie Hill

When you hear the name rough-toothed dolphin, you would be correct to assume that their teeth are a feature we can use to identify them. However, even though there are distinctive vertical ridges on their teeth, you would need to be very close to the open mouth of a rough-toothed dolphin to see this identifying trait! A more practical common name for these dolphins would take into account the very distinct appearance of their head. Rough-toothed dolphins have an unusual forehead, which slopes gently down from the blowhole all the way into the narrow rostrum (or beak) without any demarcation between the melon and the beak. The melon is a very specialized waxy-fatty organ positioned on top of the head in front of a toothed-whale’s eye that allows for the function of echolocation, a type of bio-sonar these animals can use to navigate and find prey. A good example with which to contrast the head of a rough-toothed dolphin is the head of a bottlenose dolphin, which has a distinct crease separating the melon from the short, stubby beak (from which bottlenose dolphins get their common name). Completing the unique look of the rough-toothed dolphin head are its large, bulging eyes and varying degrees of white on its lower jaw that typically get whiter with age.

The lower jaws of rough-toothed dolphins typically get whiter with age. Photo credit: NOAA Fisheries/Michael Force

Who are you calling a slow dinosaur? Extremely intelligent, now that’s more like it! Photo credit: NOAA Fisheries/Carrie Sinclair

Another interesting characteristic of this species is the evolution of large appendages (pectoral flippers and dorsal fin) relative to their body size. Rough-toothed dolphins have large pectoral flippers with rounded tips, which is typical of the body plan of slower-moving cetaceans. Normally, the fastest-moving dolphin species will have smaller and pointed fins that are more suitable for high speeds and quick directional changes. This is not to say that rough-toothed dolphins are slow by any means, just in comparison to other open-ocean dolphin species. In fact, slower methodical movement better explains the behaviors we generally observe among groups of rough-toothed dolphins hunting for fish around floating debris or hanging out at the periphery of tuna schools.

Rough-toothed dolphins have been described as extremely intelligent. Cetaceans, in general, are considered one of the three peaks in brain evolution history along with primates and elephants. Rough-toothed dolphins have the highest encephalization quotient among any cetacean in the world, which is a measure of their brain size (and development of that big brain) relative to their body size. These dolphins clearly demonstrate their intelligence in their environment as they are observed hunting for food in clever ways, without relying solely on speed.

Rough-toothed dolphins generally live in fluid fission-fusion societies, where members of groups can interchange frequently, but still maintain very close social bonds with each other. Group size is generally on the smaller side, ranging from just a few animals to about 100, but these individuals can be spread out over a large distance. These smaller subgroups are likely formed with the intent of stealthily hunting for prey, which is one possible reason why they can be difficult to detect during a visual survey.

A group of rough-toothed dolphins spotted about 10 nautical miles west-northwest of Kaʻena Point on Oʻahu. Photo credit: NOAA Fisheries/Andrea Bendlin

A primary goal of HICEAS is to estimate the size of cetacean populations in Hawaiian waters using a method known as line-transect sampling. Abundance estimates from the last HICEAS (in 2010) indicated that the rough-toothed dolphin was the most abundant species in the study area. This high abundance estimate was linked to a parameter in the estimation process that suggested that rough-toothed dolphins had the lowest probability of being detected on the trackline, given the sea conditions during the survey effort. Indeed, experienced observers have noted that rough-toothed dolphins are difficult to detect given their relatively small group sizes and subtle surfacing behavior, sometimes seeming to suddenly appear and oftentimes mixed with other species. However, researchers at the Cascadia Research Collective found that the sighting characteristics of rough-toothed dolphins around the main Hawaiian Islands were almost identical to those of bottlenose dolphins and that the resighting rates of individual rough-toothed dolphins were high enough to indicate that at least island-associated populations are not especially large. Are rough-toothed dolphins really the most abundant cetacean species around Hawaiʻi or is there something about their detectability or behavior that we’re not accounting for in our data collection or abundance estimation methodology?

This map of the Hawaiian Islands shows all of the HICEAS 2017 survey effort (white lines), with rough-toothed dolphin sightings shown as blue circles. The red shading is a focus area around the main Hawaiian Islands, and the green shading is the Papahānaumokuākea Marine National Monument, with darker shading where the Monument was expanded in 2016.

The answer may lie in acoustics. The acoustics team generally has a higher encounter rate than the cetacean observers, meaning that we often hear rough-toothed dolphins that they never saw, and we don’t have to worry about the effects of survey conditions and sneaky surfacing behavior. Acoustics may help us better understand the circumstances that lead to missed visual detections and refine our abundance estimates accordingly. Rough-toothed dolphins, like other delphinids, produce both whistles and echolocation clicks that are believed to aid in socializing (whistles) and finding food (echolocation clicks). Their vocalizations have the potential to be confused with the dolphins known as “blackfish” (e.g., killer whales, false killer whales, and pilot whales) because, like blackfish, rough-toothed dolphins produce short-duration whistles ranging from 2.5 to 10 kilohertz and clicks from 10 to 90 kilohertz. They seem to be one of the only non-blackfish species whose whistle and echolocation click frequencies overlap so closely with blackfish. What does make rough-toothed dolphins vocalizations unique from blackfish is that their whistles are simple in structure and usually have very characteristic “steps.” We do not know what has driven the evolution of this special whistle, but it helps us identify the species without needing a visual confirmation.

A spectrogram (or visual representation of sound) showing the “stepped” whistles of rough-toothed dolphins.

Have a look at the HICEAS website to find out what else we saw in the remaining days of HICEAS 2017!

 All photos taken under research permit.

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From two ships to one: The penultimate leg of HICEAS 2017

By Jim Carretta
HICEAS Cruise Leader

When we last checked in on the progress of the Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS), one of the two NOAA ships involved in the survey had completed its HICEAS 2017 mission.  That is, after three legs totaling 87 days at sea, the NOAA Ship Oscar Elton Sette hung up its HICEAS hat, leaving the NOAA Ship Reuben Lasker to carry the HICEAS torch for two more survey legs.  After a six-day in-port, the Lasker departed Honolulu on October 16th and spent 25 days at sea, returning to port on November 9th.  The scientists aboard the Lasker conducted visual and acoustic surveys for cetaceans (whales and dolphins) in the region between O’ahu and Midway Atoll, covering 1,529 nautical miles of daytime trackline.  We also collected cetacean biopsy samples for genetic analysis, filtered water samples for an eDNA study, deployed sonobuoys to listen for baleen whales, collected oceanographic samples with a conductivity-temperature-depth (CTD) unit, and surveyed for seabirds.

A rough-toothed dolphin surfaces close to the NOAA Ship Reuben Lasker. Photo credit: NOAA Fisheries/Bernardo Alps

We sighted 44 groups of at least 14 species of cetaceans, including the first minke whale sighting of HICEAS 2017, and collected five biopsy samples from rough-toothed dolphins.  Minke whales also stole the show for the acoustics team, when we heard their “boings” on both the towed array and sonobuoy stations for five days straight.  We also got our first acoustic detections of fin whales for HICEAS 2017.  These detections occurred when we deployed sonobuoys after sighting an unidentified baleen whale.  Overall, the acoustics team detected 103 groups of at least 11 cetacean species.

Daytime survey effort (white lines) and cetacean sightings (see legend) made within the Hawaiian EEZ (blue line) during HICEAS 2017 Leg 3 aboard the Reuben Lasker. The red shading is a focus area around the main Hawaiian Islands, and the area shaded in green is the Papahānaumokuākea Marine National Monument, with darker shading where the Monument was expanded in 2016.

A highlight of Lasker Leg 3 occurred on the morning of November 3rd, during rare Beaufort sea state 1 conditions, when the visual survey team detected a small whale at the surface approximately 970 miles west-southwest of Honolulu.  It quickly became apparent that we were looking at a rarely-seen pygmy sperm whale (Kogia breviceps).  In 25 years of searching for marine mammals, I have seen pygmy sperm whales fewer than 5 times, and each of those sightings lasted less than 15 seconds.  In his recent book on Hawaiʻi’s whales and dolphins, cetacean researcher Robin Baird notes that pygmy sperm whales represented less than 1% of all odontocete (toothed whale) sightings in Hawaiian waters during the course of his team’s research.  He also states that this deep-water species is the second most stranded odontocete in Hawaiian waters, which implies that its abundance is considerably greater than the rare visual detections at sea suggest.  Pygmy sperm whales are a small species (approximately 10 feet in length) that are cryptic due to their size and slow movements.  Individuals are often mistaken for a floating log as they rest motionless at the surface, with only a dorsal fin and part of the back exposed.  Pygmy sperm whales are most often encountered singly, although pairs are sometimes detected.  Previous research by marine mammal scientist Jay Barlow on the detectability of whales of the genus Kogia (which includes both pygmy and dwarf sperm whales) indicates that the probability of visual detection is close to zero the in sea state conditions commonly encountered during our surveys.  On the glassy morning of November 3rd, we watched and photographed an individual pygmy sperm whale rafting at the surface and performing slow, shallow dives.  The initial sighting occurred at 8:34 a.m. and our sighting database shows that it was last detected at 9:01 a.m., a sighting duration of nearly half an hour! Due to the extremely calm seas and cooperative behavior of the whale, nearly a dozen people were able to view this animal from the ship’s flying bridge, possibly the greatest number of people to ever simultaneously view this species in the pelagic environment.

Pygmy sperm whale detected on November 3, 2017, approximately 970 miles west-southwest of Honolulu. The bird flying beyond the whale is a White-Necked Petrel, which has a wingspan of approximately three feet. Photo credit: NOAA Fisheries/Mark Cotter

We saw 4,867 seabirds representing at least 36 species during our strip transect effort.  Although the average seabird diversity (13 species per day) was lower than the previous two Lasker legs, overall abundance was higher, averaging 214 seabirds per day.  Over the course of the leg, we detected a shift in species composition and abundance, as well as a slight increase in some local breeders and a decrease in others, as trans-hemispheric migrants neared the end of their passage through the study area.  The results of our feeding flock survey were similar to last leg, but with lower diversity.  We recorded 9,639 seabirds of at least 15 species in 51 feeding flocks.  The two most abundant species in the feeding flocks were, not surprisingly, the Wedge-tailed Shearwater and the Sooty Tern, together comprising 78% of the total birds seen.  We saw several noteworthy seabirds on Lasker Leg 3.  The most unexpected was an adult male Nazca Booby that visited the ship for almost two hours, 60 nautical miles north of Nihoa, representing the seventh known occurrence of this eastern Pacific Ocean endemic around the Hawaiian Islands.  The Nazca Booby was treated as a subspecies of Masked Booby until being elevated to full species status in 2000.  Another surprising sighting was of an immature dark morph Northern Fulmar that was seen about 70 nautical miles northwest of Laysan.  Less than five individuals of this species have been seen alive at sea in Hawaiian waters, all in November to March.

Finally, while our daily CTD deployments were generally a pretty routine operation, one night they got a little more interesting.  How, you ask?  You can find out by watching the video below, courtesy of HICEAS Acoustician Anne Simonis from the Scripps Institution of Oceanography, UC San Diego.  Thanks, Anne!

Folks, the end is in sight.  On November 15th, the Lasker set sail on its fourth and final leg of HICEAS 2017.  Keep your eyes on the HICEAS website for the final details of our five-month survey!

All photos taken under research permit.

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Who are you? Who, Who? Who, Who? Studying a cryptic marine mammal species by eDNA

By Lauren Jacobsen
HICEAS Visiting Scientist

Lauren is a Lab Associate with the Bioacoustics Research Program at Cornell University and practices veterinary medicine in western New York. She participated on a leg of HICEAS 2017 as a visiting scientist.

In the words of The Who, I am reminded of a catchy tune: “Who are you? Who, who, who, who?” As we search for the identity of a mysterious beaked whale, I just can’t help but find this to be the most fitting theme song for my expedition to the central Pacific Ocean. In mid-October, I had the exciting opportunity to participate in the Hawaiian Islands Cetacean Assessment and Ecosystem Survey (HICEAS) aboard the NOAA Ship Reuben Lasker. This was a special opportunity, not only because it was my first pelagic research cruise, but I also had the opportunity to participate in a project using environmental DNA (eDNA) to study a cryptic marine mammal species.

Will eDNA finally help us to identify a mysterious beaked whale that remains hidden from our view? Photo credit: NOAA Fisheries/Lauren Jacobsen

The HICEAS expedition is a huge collaborative effort to study dolphins, whales, seabirds, and the ecosystem of the Pacific Ocean around the main and Northwestern Hawaiian Islands. The entire HICEAS effort will span a total of 187 days aboard two NOAA Ships, the Oscar Elton Sette and the Reuben Lasker. Both ships made multiple trips, or ‘legs,’ to cover the entire study area; my 25-day involvement in HICEAS was on Leg 3 of 4 on the Lasker. My primary duty was to participate in a project to study the mysterious ‘Cross Seamount beaked whale.’ At Cross Seamount, which is located approximately 150 nautical miles south of O’ahu, unique beaked whale vocalizations have been consistently recorded, but they have yet to be associated with a known species. Compared to the more than 75 different whale, dolphin, and porpoise species that make click-type (or echolocation) noises, the clicks recorded from the animals at Cross Seamount have distinctive beaked whale characteristics. That is, they have a frequency sweep within the click and are very long in duration relative to the clicks produced by most dolphin species. The whale’s true identity has yet to be determined, but it has been affectionately referred to as the ‘Cross Seamount beaked whale’ because that is where it was initially recorded in 2005.  These clicks have also been recorded at other sites across the tropical waters of the central and western Pacific. The distribution of those recordings suggests that this is a beaked whale species in the genus Mesoplodon, although this project aims to resolve this mystery once and for all.

The location of Cross Seamount in the HICEAS study area, which is the entirety of the U.S. Exclusive Economic Zone around Hawaii (blue line). The red shading is a focus area around the main Hawaiian Islands, and the area shaded in green is the Papahānaumokuākea Marine National Monument, with darker shading showing where the Monument was expanded in 2016.

Since beaked whales are generally difficult to see (even in low sea states), and these unidentified vocalizations occur almost exclusively at night, previous efforts to pair acoustic detections with visual observations have had little success.  The HICEAS 2017 team wanted to explore other options for identifying this species, and collection of eDNA offers an opportunity to obtain genetic confirmation of the whale generating these calls. In an attempt to identify the cryptic Cross Seamount beaked whale to species, the team collected seawater samples at several depths in places where the acoustics team was hearing Cross Seamount beaked whale signals, and at several locations over Cross Seamount itself, in hopes of capturing a speck of tissue (like sloughed skin) the elusive whale left behind in the water. Seawater was collected at the surface and at a range of depths (0–1,000 meters deep) with a conductivity-temperature-depth (CTD) unit, which has sensors for making oceanographic measurements and bottles for collecting water samples throughout the water column. The CTD was also outfitted with an acoustic recorder to evaluate whether Cross Seamount beaked whales were heard during the time of the seawater collection.

Acousticians Shannon Coates (Lead for the Lasker) and Jenny Trickey show off the CTD equipped with an acoustic recorder and the seawater collection system for the Cross Seamount beaked whale eDNA study. Photo credit: NOAA Fisheries/Suzanne Yin

The HICEAS team conducted these enhanced CTDs on all three legs of the Lasker, collecting over 170 liters of seawater. The seawater samples were frozen following collection, awaiting my arrival on Leg 3. Once I was aboard, I defrosted and then filtered each of the samples through a polycarbonate filter, which is a special type of filter paper, to concentrate the DNA in the sample. Once the seawater was reduced on the filter paper, the paper was folded and spiraled into an ice cream cone-like shape and then placed into a microtube. A preservative called Longmire’s solution was added for storage and later transport back to the lab. After docking, the samples will be sent to Dr. Scott Baker and his team at the Cetacean Conservation and Genomics Lab of Oregon State University, who will investigate the genetic material in these samples. Check out the DNA Surveillance website to learn more about this process. These methods have been successful for identifying other marine and terrestrial species, so stay tuned to see what we will find! “Oh I really wanna know. Oh tell me who are you,” beaked whale?  “you, you, you, ah you?”

Lauren next to the laboratory setup of the filtering equipment and holding a filtered seawater sample secured in a microtube. Photo credit: NOAA Fisheries/Anne Simonis

“Whooo”…will we see next on HICEAS?  “Who, who, who, who?”

Lauren’s trip was funded by the Office of Naval Research and made possible by the collaborative efforts of the Pacific Islands and Southwest Fisheries Science Centers, Cornell University, and Oregon State University.

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