Humpback whales

For Immediate Release:

Ed Lyman-HIHWNMS-NOAA Fisheries Permit #782-1719 (Original image has been altered to include Wave Glider) - Copy1.png

  

 

Autonomous (Robotic) Wave Glider Mission from Hawaii to Mexico Detects Humpback Whale Calls in Tropical Mid-Ocean and Questions Definition of Winter Breeding Assemblies 

Current NMFS humpback whale management policies assume Mexico and Hawaii winter assemblies are distinct with separate status and management warranted

 

BIG ISLAND, HAWAII July 1, 2019 – Jupiter Research Foundation and Whale Trust are pleased to announce the publication of the results of the first leg of their autonomous Wave Glider HUMPACS (Humpback Pacific Survey) acoustic survey in Journal of the Acoustic Society of America – Express Letters. During a 100-day nearly 7,000 km (3,800 nm) round trip survey on a line between Hawaii and Mexico within the 2018 winter breeding season, humpback whale calls were heard in mid-ocean basin, halfway between the known near-shore assemblies. 

“They’re not ‘supposed’ to be there,” says Dr. Jim Darling, Whale Trust biologist and project partner. Humpbacks are known to assemble in specific near-shore, relatively shallow, breeding grounds in Mexico and Hawaii. “But then no one has looked in these more remote, offshore areas either.”

Mission control was from Puako, Hawaii where Beth Goodwin, Jupiter Research Foundation VP and HUMPACS Project Manager, and her team were in daily communication with the Wave Glider: monitoring status, downloading surface and underwater photographs, downloading short samples of recordings via satellite, and making course alterations if needed. 

From January 16 to April 25, 2018, the Wave Glider, named Europa (after one of Jupiter’s moons), performed a 6,965.5 km, 100-day (RT) continual acoustic survey from Hawaii towards Mexico circa 20° N. The survey resulted in 2,272 hours of recordings and included over 4,000 cetacean calls.  Of these calls, 2,048 were identified as humpback whale calls.

The humpback calls were recorded up to 2,184 km (1179 nm) offshore spanning 30 days between January 20, when the Wave Glider left Hawaii, to February 23, 2018. On many days, multiple humpback call detections were recorded (up to 377 calls over 23 hours of a day). Actual numbers of whales cannot be determined, as one whale can make many calls.

“This was risky, we had no idea if humpbacks were even out there,” says Goodwin. “And then, even if they were, there were needle-in-haystack odds of intersecting them considering the size of the Wave Glider and the size of the ocean.”

Possible explanations, suggests Darling, include an undocumented migration route to Hawaii, a separate (from Hawaii and Mexico) offshore assembly of humpback whales, or travel between Mexico and Hawaii assemblies within the same season. At the very least, these results indicate an extension of winter distribution and habitat of humpbacks. It could also be that these offshore whales have not been included in current population estimates.

Since 2016, the model used by the U.S. National Marine Fisheries Service (NMFS) to manage humpback whale populations has treated the Mexico and Hawaii winter assemblies of humpback whales as distinct populations. As such, these populations have different status under the U.S. Endangered Species Act (ESA): Mexico humpback whales are considered threatened while Hawaii humpback whales have been delisted; that is, the Hawaii population has no protection under the ESA.

This assessment is further complicated by longstanding research showing shared song between the breeding assemblies and an interchange of photo-identified individual whales between these two winter breeding grounds.

Our findings question the independence of Mexico and Hawaii humpback whale populations and illustrate the huge potential for the use of autonomous vehicles in the study of whales across remote locations of the ocean.

“We feel certain our results will encourage more research, affect how humpback and other whales are monitored, and help with management,” says Goodwin.

The paper is online: https://doi.org/10.1121/1.5111970

 

BACKGROUND

 

Wave Glider

The Wave Glider (produced by Liquid Robotics, a Boeing Company) consists of a surfboard-sized surface platform (the float) tethered by an umbilical cable to a submerged glider (the sub) 8 m (26 ft.) below the surface. The float includes a command and control unit, three solar panels, an instrument package, surface and underwater cameras and communications systems. The sub is the propulsion unit, which transforms vertical wave movement into forward motion (https://www.liquid-robotics.com/wave-glider/how-it-works/). Time-lapse series of images from the two Europa cameras, surface and underwater, are accessible on the JRF blog:
http://jupiterfoundation.org/current/2018/5/22/f2l6bevguh177l21x42gi20pegicbv

About Jupiter Research Foundation

The Jupiter Research Foundation is a 501(c)(3) non-profit scientific research organization. Established in 2003, the Foundation is dedicated to conducting innovative scientific research and finding technological solutions to problems which are outside of mainstream science and technology. Our findings are shared with the public and academic community in hopes of better monitoring and understanding the natural world. Visit https://jupiterfoundation.org/ to learn more. 

About Whale Trust

Whale Trust is a Maui-based 501(c)(3) non-profit organization whose mission is to promote, support and conduct scientific research on whales and the marine environment and broadly communicate the findings to the public. Whale Trust research programs focus on behavior, communication and social organization of whales. For more information, visit https://whaletrust.org/.


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Europa's NOT Drunk!

You may have noticed that Europa has been bouncing around a bit more than it did on HUMPACS East. Well don’t worry…it’s intentional!

The general path that Europa is following goes along 20oN latitude.

The reason that it is not going in a straight line is because there are numerous seamounts and guyots (aka tablemounts) that we are having it navigate over on it’s way to the Mariana Trench.

Seamounts are basically underwater mountains that are at least 1,000m tall. They do not actually reach the ocean’s surface. Guyots are seamounts that did, at one time, rise above the ocean’s surface, but then eroded away, flattened out, and eventually sunk back down underwater.

Why does all of this matter?

Well, since Europa is basically a very small fish in a very big pond, we need to strategically look for these humpback whales. Even though most of the time the tops of these seamounts and guyots can be found many hundreds, if not thousands, of meters below the ocean’s surface, they are actually great producers of marine ecosystems. That makes us think that we might have a better shot at stumbling upon some humpbacks in those areas, as opposed to simply out in the middle of an even deeper ocean.

There has been some research to support the statement that humpbacks seem to frequent seamounts and guyots, though the exact reason why hasn’t been determined.

The leading theories are that the landmarks serve as resting and/or feeding areas, points for navigation, and even meeting grounds (source: PubMed Central®).

Maybe they’re sharing different versions of their song? At the end of the day, we don’t really know why…yet!

If you’d like to dive a little deeper into the science and evolution of a seamount, check out our blog post Mountains in the Deep Sea.

Figure 1: Europa’s path on a nautical chart. Europa is currently traveling from East to West, and navigating over many different seamounts and guyots. (Depths are in meters).

Figure 1: Europa’s path on a nautical chart. Europa is currently traveling from East to West, and navigating over many different seamounts and guyots. (Depths are in meters).

 
Figure 2: Zoomed in image to show more detailed depths of the Horizon Tablemount that Europa traveled over Jan 16-19, 2019.

Figure 2: Zoomed in image to show more detailed depths of the Horizon Tablemount that Europa traveled over Jan 16-19, 2019.

Figure 3: Europa circling a particular seamount. We will have Europa do this from time to time to search a little more for humpbacks in areas we suspect them to be.

Figure 3: Europa circling a particular seamount. We will have Europa do this from time to time to search a little more for humpbacks in areas we suspect them to be.

If you check out the HUMPACS page, you’ll notice that from January 16-19 Europa was cruising over the Horizon Tablemount. In another two or three weeks, Europa should be traveling around the HIG Guyot. This particular guyot is of note to us here in Hawaii because it was actually discovered about 37 years ago by the “Kana Keoki” research vessel, and named after the Hawaiian Institute of Geophysics (source: Marineregions.org).

So, for those of you that were wondering, and dare we say concerned, about Europa’s up and down path…worry no more! Europa is doing exactly what we want it to do, and we’re collecting lots of great data that we look forward to sharing later on.

Until then, keep checking in and watching Europa as it makes it’s way West across the Pacific Ocean.

Also, check out our live audio stream of the humpback whales that are swimming around Puako, HI right now!

Aloha!



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Can You Hear Me Now?

When we were preparing for the first leg of HUMPACS, referred to as HUMPACS East, we found ourselves faced with a tough decision when it came to how the hydrophone should be mounted.

“Do we hang the hydrophone, or try to hard mount it as close to the sub as possible?”

When doing hydrophone operations just outside of Puako, Hawaii, we have found that you get the best audio if you hang the hydrophone at least 30 feet below the sub. This, obviously, is due to the fact that we’re basically decoupling the hydrophone from the sub. We also are able to pick up more sounds when we’re deeper.

Hearing that, you might wonder why we decided to hard mount the hydrophone during HUMPACS East.

Well, what we have also learned through years of experience monitoring the gliders off the coast of the Big Island is that when we have a hydrophone hanging, ocean currents become a much larger problem.

There are different currents at different depths, and so even though the glider (float, sub and hydrophone) are all relatively in vertical alignment, each part of them is getting pushed and pulled by a different current.

In Hawaii, it’s not that big of a deal for us because we keep the gliders in a relatively small area the majority of the time, and we can go rescue the glider if we really need to.

When sending it across the Pacific Ocean, it’s a different story. There are no rescue missions. It just has to work!

For that reason, we decided to keep the hydrophone hard mounted directly to the sub, with no separation or “acoustic isolation”. We knew that the background noise (flow noise, wing springs and rudder) would be very loud. However, we confirmed that even with all this loud background noise we would be able to detect humpback whales, as we did a proof of concept with humpbacks singing off Puako before sending it east. All this was worth it to know that the hydrophone would be very safe. After all, we’d never made this trek before, (no one had for that matter), so we didn’t know what kind of abuse it might encounter. Sharks, rubbish, wear and tear, getting tangled up by the umbilical. These were all big concerns, and, at the time, we needed to play it as safe as possible.

HUMPACS East  Copper Hydrophone Mount

HUMPACS East

Copper Hydrophone Mount

All these concerns continued to stand true with HUMPACS West. We still agreed that the unknowns about drifting were too much of a risk, so we mounted it close, but not hard mounted.

Since we did not encounter any drift that could have entangled the hydrophone, nor any shark bites, for HUMPACS West, we decided to see what the minimum distance was that we could drop the hydrophone and achieve higher quality audio. We still needed to keep the hydrophone safe, but we wanted more vibration isolation between the sub and the hydrophone itself.

After testing many different materials and changing up the distance of which we dropped the hydrophone below the sub we came to the conclusion that a three inch drop using EPDM Fiberglass Reinforced rubber sheets to mount was the way to go. It improved our audio and also kept the hydrophone safe at the same time. As an additional safety measure, we added a deflector bar to the bottom of the sub to help prevent shark bites and entanglement on the hydrophone.

HUMPACS West  EPDM Fiberglass Reinforced Hydrophone Mount

HUMPACS West

EPDM Fiberglass Reinforced Hydrophone Mount

Take a look at the two spectrograms below and see the difference in noise levels. HUMPACS West is exponentially more quiet than HUMPACS East. There is also almost a complete elimination of the 650Hz and 975Hz harmonics from the rudder module. This, alone, is a very improved piece of the puzzle, as the primary range that we listen and view the humpbacks’ song is in that <1KHz range.

HUMPACS West Spectrogram

HUMPACS West Spectrogram

HUMPACS East Spectrogram

HUMPACS East Spectrogram

As you can see, HUMPACS West is much more quiet as far as background noise goes. What’s that do for us? Well, if the background noise is less, then it becomes substantially easier to detect humpback whales (and other species). This improvement should greatly improve our post processing efforts, and is more efficient at detecting as many humpbacks as possible.

Currently, Europa is a little over 700nm (nautical miles) west of the Big Island of Hawaii. Follow its journey on the HUMPACS page!

Aloha!


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We're Back!

Europa is back in the water on her second mission to listen for humpback whales, just in time for the Holidays. Last year, Europa successfully completed the East Leg (from Hawaii to the Baja California Seamount Province and back), and now she will swim to the Mariana Trench and back (the West Leg). Biologists have wondered if there is an undiscovered distribution of humpback whales among the seamounts between these areas. Since the East Leg was successful, we hope Europa’s journey west will be triumphant. You can track Europa’s path on our website. Stay tuned for more updates!

Wishing you a Happy Holiday and a Joyful New Year!


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Photo Time-lapses from Europa

Almost one month has passed since we recovered Europa, and we are still in the process of analyzing data, however; we have reviewed all of our photos. During the 3.5 month mission, we had a camera attached to both the top and bottom of Europa’s float that took above and underwater images periodically on a daily basis.

The top camera was mounted on the back of the float looking forward, which enabled us to inspect the float and antenna deck during the mission. The bottom camera looked down towards the sub underneath the water to help us check the sub and umbilical. In the previous blog, we mentioned we had a gooseneck barnacle that grew over the underwater camera lens. Even so, we were still able to get glimpses of the sub for diagnostic purposes.

Over the 3.5 month mission, the top and bottom mounted cameras took over 500 photos each. We have constructed two time-lapse videos of the above and underwater pictures, which are each a little over three minutes long. We were able to capture some fantastic photos! The sunset photos and waves washing over the float are captivating, and it’s fun to watch the barnacle grow over time in the underwater footage.

In our next blog, we will post some sample of audio files of some exciting sounds we’ve heard, including odontocetes whistles and clicks, echolocation, and other unusual noises. Stay tuned!


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Land Ho!

Europa  approximately 40 nautical miles off South Point (the red star).

Europa approximately 40 nautical miles off South Point (the red star).

Europa is nearing the shores of Ka Lae (ka-lie), or South Point, which is the southernmost tip of the Big Island and the United States. Archaeological excavations and Hawaiian tradition indicate Ka Lae, meaning “the point,” was the first place the early Polynesians occupied in Hawaii, as early as A.D. 124. The area is an official National Historic Landmark (NHL) because of its cultural significance and importance. Claiming this region as an NHL enables protection and preservation under the National Historic Preservation Act (NHPA).

Two prevailing currents converge off the coast of South Point: Kāwili and Hala’ea.The Kāwili, or the Hawaiian Lee Counter Current, flows from west to east all the way from Asia. This current is thought to have helped early Polynesians find the Hawaiian Islands while traveling from their original homeland: Kahiki.

The Hala’ea, also known as the North Equatorial Current, travels east to west by trade winds and is named after the greedy chief, Hala’ea. Oral histories and texts say Hala’ea ordered his men to throw all of their aku (tuna) into his canoe so he could claim all of the fish for himself. His men threw so many fish into his boat that it capsized, and he was swept out to sea by a strong current. Hence, the current bears his name.

The currents bring many nutrients and make the waters off Ka Lae abundant in fish. However, they also carry a vast amount of trash that piles up along the coastline. The majority of the waste is plastic, likely from the Great Pacific Garbage Patch carried by Hala’ea.

Since the first settlement of Polynesians, communities within Ka Lae have relied on fish as their prominent resource. In the 1950s, the University of Hawaii and the Bishop Museum excavated a site called Pu’u Ali’i. This location is thought to be one of the first dwellings in Ka Lae established by fishermen. Archaeologists found many different types of large fish hooks and tools to make them, including coral and stone abraders. Further excavations in Ka Lae revealed a fishing shrine (Ko’a) within the Kalalea Heiau. This shrine was created for the fishing god, Ku’ula, to maintain the abundance of fish. Other remaining cultural sites within the area are Lua o Palahemo, the Canoe Mooring Holes, and Lua Makalei.

The federal government manages NHL’s, and although it protects Ka Lae, it does not provide enough support on a local and state level. As environmental and cultural regimes continue to shift in Hawaii, significant stakeholders of Ka Lae (community members, the State of Hawaii, and the Department of Hawaiian Homelands) have recognized the need for additional preservation, conservation, and management efforts. Thus, since 2016, a new management plan has been underway that implements community-based management strategies of long-term land stewardship, and natural resource and cultural management.

Europa was able to swim past South Point without any issues from the currents as she traveled towards Mexico. We hope she doesn’t have any trouble as she passes it once more on her way home. Once she wraps around the point and gets north of Milolii (see map above), we plan to retrieve her with our vessel, the May Maru. She has approximately 80 nautical miles to go until retrieval. Track the rest of Europa's journey on our website and stay tuned for exciting new updates after HUMPACS concludes!


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Oh Barnacles, those Crusty Foulers!

Barnacles are pesky little creatures. Have you ever heard of Barnacle Bill, the foulest sailor? Well, he’s named that for a reason. Sailors, shipowners, and mariners hate barnacles because they attach to the bottoms of boats and ships (biofouling). Large barnacle colonies weigh marine vessels down, which causes them to drag and burn more fuel. In our case, they stick to the bottom of our Wave Gliders and block the camera’s field of view.

Biofouling is a process where invertebrates, including barnacles, mussels, sponges, and corals stick to marine surfaces. For this to occur, a biofilm consisting of bacteria, algae, seaweed, or diatoms must first form on the substrate. The formation of biofilm is dependent on many environmental factors, however, once it develops, the biofoul rapidly increases.

To prevent biofouling, we experimented with an antifouling Coppercoat™ paint and a 90-10 copper-nickel alloy before deploying Europa. First, we painted the entire vehicle with the Coppercoat™. If we didn’t do this step, a thick layer of barnacles and algae would encrust Europa and significantly weigh her down. We then sheathed the camera within a copper-nickel casing with an acrylic lens in hopes that biofouling would not occur.

This image displays the bottom of Europa's float, painted with a Coopercoat paint. The Camera (facing down) is encased in a copper-nickel alloy housing with an additional copper ring around the acrylic lens to prevent biofouling.

This image displays the bottom of Europa's float, painted with a Coopercoat paint. The Camera (facing down) is encased in a copper-nickel alloy housing with an additional copper ring around the acrylic lens to prevent biofouling.

As a secondary safeguard, we incorporated an additional biofoul resistant copper ring around the lens. Unfortunately, that didn’t work as we’d hoped. Europa has had a barnacle progressively developing over the camera’s field of view for over a month, and there’s nothing we can do about it. Their lifespan is 8-20 years so that barnacle will keep growing until Europa’s mission is complete, at which time we will identify this barnacle. Below is an image sequence of the barnacle forming in the camera lens.

So, besides being annoying, what is a barnacle’s purpose and ecological role? Barnacles are in the Crustacea taxon, meaning they are related to shrimps, lobsters, and crabs. They are most abundant in areas where upwelling occurs, worldwide. As larvae, barnacles function as zooplankton; microscopic organisms that float around as food for other critters. As they morph into adulthood, they affix themselves to surfaces, such as rocks, ships or whales, and eat microscopic plankton through feather-like appendages called cirri. Primarily, they play a trophic role in balancing plankton populations.

Barnacles secrete a robust adhesive substance like super glue that has enormous medical and engineering potential.  Scientists have discovered barnacle’s glue binds the same way humans’ blood does when it clots. By researching it further, scholars can gain more information about how to prevent barnacles from fouling.


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Commotion in the Ocean

Visibility in the ocean is relatively weak, especially at a depth of 400+ meters, making vision rather useless in the deep sea where whales reside. Sunlight doesn’t travel very far into the ocean. However, acoustic vibrations travel faster and farther in water than they do on land (Image 1). Therefore, sounds are valuable tools in deep, dark environments where whales use their ears as their eyes.

Image 1: An  image by NOAA.  A visual representation how far low-frequency sounds travel through the ocean.

Image 1: An image by NOAA. A visual representation how far low-frequency sounds travel through the ocean.

Animals in marine environments rely on sound for basic survival needs. For example, baleen whales, which are the largest of marine mammals (including humpback, blue, fin, right, and gray whales, etc.) emit long, low-frequency sounds ranging from 7Hz to 22kHz that travel long distances across the ocean. Baleen whales also travel long distances making periodic migratory trips from their feeding grounds to their breeding grounds. Thus, scientists hypothesize that baleen whales use low-frequency sound in part to aid in navigation and long-distance communication.

The ocean is already a naturally loud environment, and humans have significantly increased that noise level. Anthropogenic noise pollution (such as ship traffic) obscures animals' communication, and could potentially have adverse effects on marine life; especially baleen whales (Image2). Although, considerable scientific uncertainty remains. Many factors influence the degree of impact, including multiple characteristics of the sound, and the animal. Potential impacts include behavior alternation, temporary hearing loss, and various communication interferences (Image 3).

Image 2: An  image by the University of Rhode Island . A visual representation (in frequency (Hz)) of how anthropogenic noises interfere with marine mammals. Baleen whales' sounds are masked by seismic, ship traffic and bubbles &amp; spray noises.

Image 2: An image by the University of Rhode Island. A visual representation (in frequency (Hz)) of how anthropogenic noises interfere with marine mammals. Baleen whales' sounds are masked by seismic, ship traffic and bubbles & spray noises.

Image 3: An  image by SSPA . A visual representation of anthropogenic noise interference with marine animals.

Image 3: An image by SSPA. A visual representation of anthropogenic noise interference with marine animals.

Scientists study sounds and their relationship with the environment over a wide range of scales (both spatial and temporal) via a new science called ecoacoustics. They investigate sounds to understand their evolution, functions, and properties under environmental stressors and changes. Sounds are used as tools to monitor ecological factors, such as biotic and abiotic relationships, and animal behavior, diversity, abundance, distribution, etc.

Using hydrophones to record marine acoustics have helped scientists gain knowledge, and a better understanding of the ocean and how we’re affecting it. We are proud to say our Wave Gliders (WGs) don’t produce noise that’s harmful to whales or other marine life. So far, we think WGs do not deter animals: fish aggregate around them, birds rest on them, whales swim near them, and dolphins bow ride them. The WG has revolutionized the way we collect data and monitor the ocean. The hydrophone we attached to Europa is gathering acoustic data 24/7 through which we hope to gain more knowledge and understanding of the sea. Additionally, we expect our data will create a baseline, and contribute to marine ecoacoustics, as well as, support conservation efforts and the management of marine resources.

Europa Update:

Europa is approaching our second seamount; we’re within 25 miles! Stay tuned for a seamount update, the ecology of seamounts, and the habitats they provide in our next blog.


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