I didn’t give much thought to shipping until I started doing my PhD on whales and dolphins. Food magically appeared onto store shelves out of thin air, where I bought it. I don’t think most of us give much thought to where our food comes from, but once I started paying attention how things get around, it was hard to stop. This is especially true on a remote tropical island, like Hawaii. Here, every once in a while, certain foods aren’t to be found for love or money. My steps echo in the empty bread isle, and when I beg for just one slice of delicious whole grain the store employee will say, “Sorry, no can. Bread shipment comes Tuesday.”

About 85% of the food consumed in Hawaii is imported from somewhere else. Most food arrives in Honolulu on a container ship, which is then unloaded and redistributed into shipping barges. These barges are pulled by tugboats to what are known here as the “neighbor islands” of Kauai, Molokai, Maui, Lanai, and the Big Island. The shipping barges are very different than the container ships. First of all, they can’t get anywhere on their own - they need a tugboat to pull them. The tugs I work on have a maximum travel speed of about 8 knots (10 miles per hour), which is quite a bit slower than the typical 20-25 knot travel speed of a container ship.

Tug boats pushing a barge against the dock. Photo by Alexis Rudd

A tugboat towing a barge is optimally designed for my type of research, which uses underwater sound to find whales and dolphins. I record these underwater sounds through a hydrophone, which hangs off the back of a barge. Sound goes up a cable from the hydrophone, and is recorded onto a custom electronic recorder, called an EAR (Ecological Acoustic Recorder [A]). The barge is towed from a cable, about 900 feet behind the tugboat. This distance gets my hydrophone far away from the noise of the tug. Another advantage is that tug boats travel back and forth between the Hawaiian Islands twice a week, which means that if I had a couple of handy clones to share the work I could collect acoustic data from Kauai to the Big Island one hundred times per year. Since I don’t have any clones (or interns, for that matter), I only go out every 11-14 days. I’ve been on a tugboat 74 days in the last year, which, according to the crew, is about enough for me to get hired.

Why bother spending so much time on a tugboat listening for cetaceans (whales and dolphins), especially in Hawaii? The truth is, we actually don’t know much about cetaceans in Hawaii. Most of the knowledge of Hawaiian cetaceans actually concentrates on a few well-studied species: the humpback whale and the Hawaiian spinner dolphin. These species are frequently found near to shore or in calm waters: spinner dolphins “rest” in near-shore bays, and humpback whales spend the winter in Maui’s calm western lee.

Hawaiian Spinner Dolphins photographed from the bow of the tugboat near the Big Island. Photo by Alexis Rudd

In addition to these well-studied species are 23 other species that occur in Hawaii but are less well studied, such as false killer and minke whales [B],. These remaining deep-water species are less well known simply because they don’t often hang out in nice, calm water close to the shore. The water offshore in Hawaii can be dangerously rough. Wind and swell builds up across half the Pacific Ocean, creating the famous surf of Jaws and Pipeline. These conditions are too dangerous to take a small (<50 ft) research boat into, and because of this, much research on the deep-water species has also been concentrated into the westward lees of the islands (the prevailing wind in Hawaii is from the East).

The Big Island of Hawaii creates the largest lee, allowing researchers to get far out to sea. In contrast to these relatively calm leeward waters, the conditions between the main Hawaiian Islands are, to use a surfer term, gnarly. Wind traveling across the Pacific Ocean is diverted around the volcanoes of Maui and the Big Island and rushes through the gap between them. Wind speeds in the channels can average about 25 miles per hour (Beufort Wind Scale 6). At these wind speeds, foam and rough water makes it very difficult to see whales and dolphins.

Wind speed in the waters around the Hawaiian Islands. Image by Alexis Rudd, data provided by Hawaii’s Wind Engery Resource and the National Renewable Energy Lab

Fortunately, even when you can’t see cetaceans, you can often hear them. Dolphins and whales use sound underwater for communication and predation. It is actually easier to find some species using sound than vision [C]. This is where the tugboat comes in again – these boats are large enough to safely cross the dangerous waters of the channels, and they do it year-round. In addition, because they are going anyway - I can just hop on with my equipment and gather data, without having to spend thousands of dollars on renting a boat big enough to cross the channels safely. They even give me a place to sleep and feed me (a big deal for a graduate student).

After I make the recordings, I can feed the cetacean sounds into a computer program, which will analyze their characteristics to give a species prediction [D]. Doing research on vessels that are used for commercial enterprise is known as using “platforms of opportunity.” These platforms are already there, so I am taking the opportunity to use them. Other oceanic projects using platforms of opportunity has included plankton research from container ships and visual cetacean surveys from ferries, but these projects are relatively rare.

Young Brother’s crew members sitting on the lower deck as the tug passes Aloha Tower in Honolulu. Photo by Alexis Rudd

As a blonde haired, blue-eyed woman, I get a lot of paternal advice about working with the guys on the tugboat. “Fatherly advice” is one of the more annoying aspects of being a young woman scientist. I already have a (wonderful) father, and he’s got the fatherly advice market cornered, thanks. Young women in science don’t need fatherly advice - they need good mentors. This advice mostly consisted of warnings about how tough the tugboat crew would be. I wasn’t sure what to expect on the first trip, but I discovered that the guys are just as variable as anyone else. Yes, there’s a higher likelihood of teriyaki pig’s feet in the fridge (I tried it, seriously YUCK) than in my house. But once you get to know these guys, we actually have a lot in common. The captain of the tug I was on last week volunteers at a National Park to replant native plants. The A.B. (able-bodied sailor) raises local beef. One of the mates can’t stop showing me pictures of his dog, whose name is Princess (I swear). They’re not all angels or teddy bears, but neither are they the enemy.

I travel with the tugboats on two of their routes around the Hawaiian Islands; between Honolulu and Kauai, and between Honolulu and the Big Island. If the weather is good, I stand outside and look for cetaceans. If the weather is bad (waves are coming over the bow and splashing me – the crew gets a kick out of this), I come into the bridge and watch as best I can. This video from last week shows how much the boat tilts during “rough” weather:

When I get to the Big Island, I climb from the tugboat to the barge, and pull my recording equipment out of the water to download the sounds and make sure everything is working properly.

I haven’t analyzed all of my data yet. It takes a lot of time to listen to 864 hours of recordings. Regardless of what my data shows, I hope that the information can help inform research in the future. Are we missing a huge chunk of whale and dolphin activity by sticking to the nice smooth water, or is that where they hang out, anyway? I also get very excited about the idea of using platforms of opportunity on a larger scale. Commercial ships cross most of the world’s waters – imagine if every one of those vessels was equipped with a device that listened for dolphins. Of course, that brings up another host of problems; including the fact that shipping noise stresses whales, and that many whales are killed when ships hit them.

Global shipping routes that could possibly be used for science. From NCEAS at http://www.nceas.ucsb.edu/globalmarine/impacts

Is it possible for a moral scientist to partner with commercial shippers that can cause this kind of harm to their study species? Fortunately, I don’t have to wrestle with that problem yet. To the best of my knowledge, none of the tugs I work on has ever hit a whale, and their traveling speed of less than 10 knots makes them less likely to hit one. I’ll cross that moral bridge once the big shipping companies let me start recording from their boats. However, my experience working with the tugboat crews has convinced me that if we don’t at least try to communicate and work together, we’ll always fail.

Funding for this project was provided by the Office of Naval Research, Ocean Sensing and Systems Applications. Young Brothers Shipping provides boat time, accommodations, and other logistical support. Mahalo nui loa.


[A] Lammers, M.O., Brainard, R.E. and Au, W.W.L., Mooney, T.A. and Wong K. (2008). “An Ecological Acoustic Recorder (EAR) for long-term monitoring of biological and anthropogenic sounds on coral reefs and other marine habitats.” J. Acoust. Soc. Am. 123:1720-1728.

[B] The ranges of these species are taken from Jefferson, T.A., Webber, M.B., and Pitman, R.L. 2008. Marine Mammals of the World: A Comprehensive Guide to their Identification. Academic Press. Oxford, UK.

[C] Barlow, J., and Taylor, B.L. 2005. Estimates of sperm whale abundance in the northeastern temperate Pacific from a combined acoustic and visual survey. Marine Mammal Science 21: 429-445.

[D] Oswald, J.N., Rankin, R., Barlow, J, and Lammers, M.O. 2007. A tool for real-time acoustic species identification of delphinid whistles. Journal of the Acoustical Society of America 122(1): 587-595.