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Diving Deeper: Animal Tagging

Episode 46 (April 25, 2013)

HOST: Today on Diving Deeper we explore the research method of animal tagging - from how it's done to why scientists find this data so valuable. I'm your host Kate Nielsen.

To help us explore this topic, today we will be joined by Zdenka Willis. Zdenka is the director of the U.S. Integrated Ocean Observing System - a NOAA-led national partnership. Hi Zdenka, welcome to our show - again for the second time!

ZDENKA WILLIS: Kate, it's great to be here this morning.

HOST: So, Zdenka, let's get some terminology out of the way, just to get everybody on the same page - does telemetry mean the same thing as marine animal tagging?

ZDENKA WILLIS: You know Kate it took me awhile to figure out the terminology myself. So, telemetry can refer to almost anything that emits a signal at a distance. So it's important for us to have the words marine animal telemetry. But yes, a sensor with a signal attached to an animal is a tagged animal, also referred to as marine animal telemetry. There are other animal telemetry applications in which the animal is not necessarily tagged, such as passive acoustic receivers detecting whale vocalizations.

HOST: OK, very interesting, I did not know that. So, why do we do animal tagging? What is the benefit of this?

ZDENKA WILLIS: Data from these animals are transforming the way scientists study our waters and opening up new data sources. The Integrated Ocean Observing System or IOOS is making marine animal tagging a priority because it really will improve the lives of Americans. The vastness of the ocean limits our ability to observe. This technology is leading to profound advancements in understanding these animals and how they interact where they live. The knowledge translates to a better understanding of our planet and emerging issues on climate change and improvements in the management of marine living resources.

They collect valuable data at the depths of the ocean from remote and difficult to reach environments where conventional oceanographic sensing techniques are technically not feasible or economically unviable. This technology allows researchers to investigate how animals use their three-dimensional world and quantify important biological aspects of their environments. This data can be used to improve ocean forecasting by reducing errors. In fact last year, IOOS and Navy's Office of Naval Research funded a project that made 3,000 tag tracks available to both Navy and NOAA modelers.

As well they inform federal and state fisheries management, conservation, and sustainable use management policies. There's also a commercial aspect to this effort in providing information and guidance to maintaining sustainable and commercial fisheries. Fisherman know that to remain viable they need to decrease their by-catch and avoid endangered species and this tag information can help them do that.

HOST: OK, so you've given us a lot of great benefits, a lot of different reasons for why we do animal tagging. Let's talk just a little bit about what the tag is like. What exactly is the tag that you use? What does it look like/what is it made of? What can you tell us about that?

ZDENKA WILLIS: So think of little tiny computers that record and store data about the animals and their environment. Generally, a researcher must recover a tag to download the data, we call that an archival tag. Other tags can transfer information acoustically or by satellite. Sometimes, we insert them inside the body of the animal and other times they're on the outside. So think of a little chip or a microphone.

HOST: Is it heavy for the animal or are there different types of tags that you use for different sizes of marine animals?ZDENKA WILLIS: We do. The type of tag and the size of the tag is dependent on the animal and the information we want to collect. Some are really as small as a pill and a whale, as you can imagine, can collect something larger. So you wonder if this actually interferes with what the animals do and it doesn't. We've actually watched elephant seals and we've studied them physically with these tags on there and we see no change in their movement and in fact they have mated successfully. So we don't see anything changing in their social behavior.

HOST: That's great. Which animals get tags? Are there certain species that this tagging works better with than others?

ZDENKA WILLIS: Yeah, there are many things that we tag. We tag salmon, sturgeon, halibut, seals, sea lions, and fur seals, fish from very small to large ones like tuna and sharks, whales, eels, turtles, seabirds like albatross, squid, crustaceans, and others. It depends on what we're trying to study is what animal we'll tag and also collectively all of these tags tell us a significant amount about their behavior. So depending on what we need to study and what we want to study, that's what we'll tag.

HOST: So Zdenka, how are tags attached to the animals? Is it safe?

ZDENKA WILLIS: First, let me tell you it is safe. We attach them in various ways. Some of them we actually surgically insert into the body. Some of them are like getting a shot at the doctor, so a little pinch. Others we even glue on in the case of seals, seabirds, and most turtles. We have evaluated those animals. It does not hurt them and they thrive.

Yes, the tags are safe. As in most scientific studies, sometimes things don't always go perfectly. But the people who are doing the tagging, they have such a love for the animals and the environment. The last thing they want to do is hurt the animals. They're really trying to help them by understanding their behavior so yes, it is safe.

HOST: Thanks Zdenka. Are tags removed after so much time or do you ever lose tags?

ZDENKA WILLIS: So it depends on the type of tag. There are some tags which the scientist will remove. Some of them are programed actually to release from the animal and come to the surface and through their signal, we'll track them down. And of course, yes, some of them get lost, some of them we recover, and some of them we don't. We had one that we thought we were tracking large squid on the bottom of the ocean and really what we think it was was a tag that was just sitting on the bottom of the ocean.

HOST: Oh no! So onto this data then that you receive, what kind of data do these tags actually collect?

ZDENKA WILLIS: So we collect a number of environmental information like temperature, conductivity, light level, oxygen, and chlorophyll, and equally exciting is we collect information about the animals themselves, like their migration routes, how deep do they dive, where do they live, where do they hang out, where do they eat.

HOST: So this really is a wealth of information then. The data that you're downloading, it actually helps the animals carrying the tags. Can you explain this to us a little bit more?

ZDENKA WILLIS: Sure. I talked about climate change and how these data helps the U.S. earlier. But it also really helps the scientists better understand the habitat requirements of the marine animals, how they move with the flow of tides and currents, and it provides insight on how they may be altering their behavior or migration patterns in response to climate change. We really need to understand what's happening before anyone can help the animals.

It is a low cost, low risk of the scientist helping to discover where the animals are going, what they're doing, and what the environments are like when we can't actually see them and how it's affecting their behavior.

HOST: So Zdenka, I know IOOS is a national endeavor and you've got partners from academia, industry, non-governmental organizations, and state, local, tribal government entities, federal partners - just all across the board. Who are the partners that you are bringing together in the animal tagging world to do this work?

ZDENKA WILLIS: So before I talk about the actual partners, I need to bring up a program called the Census of Marine Life. That was a ten-year effort, funded by the SLOAN Foundation, that concluded in 2010. But it really was the foundation for all of the projects that are ongoing today. That was a very large program that had three goals: assess diversity - how many different kinds; the distribution - where they live; and abundance - how many in the marine life. And without that foundation, the programs that we have today, really would not be where they are in their maturity.

So when we look at it from a federal and state perspective, within NOAA, the National Marine Fisheries Service and their Science Centers are very active in tagging. The United States Geological Survey, the United States Navy through their Office of Naval Research, the Army Corps of Engineers, the Fishery Commission, and also within NOAA, our Chesapeake Bay Office. We have a host of academic partners, the world-renowned Tagging of Pacific Predators, or TOPP, is run out of Stanford University with a tremendous list of their own international and national partners; the Hawaii Institute of Marine Biology out of the University of Hawaii; the University of Delaware's Atlantic Cooperative Telemetry Network; the University of Alaska Fairbanks; the University of California, Santa Cruz; Rutgers University Institute of Marine and Coastal Sciences; and St. Andrews University in Scotland.

So internationally, the Canadians are leading the ocean tracking network with the Global Ocean Tracking Network, or OTN. During 2012, OTN deployed 1,025 acoustic receivers worldwide. Their lines included sites in Canada, Australia, South Africa, the Azores, United States, and Norway. There's also a partnership with industry - the industries who make the tags - Lotek Wireless, Vemco, and WildLife Computers.

And, through our own U.S. IOOS regions, IOOS is funding tagging operations. The Great Lakes Acoustic Telemetry Observation, the Pacific Islands Ocean Observing System, the Gulf of Mexico Coastal Ocean Observing System, and the Alaska Ocean Observing System are all funding the purchase of tags and the deployment of those tags.

HOST: Thanks Zdenka, that gives us a nice holistic picture of who is doing this and kind of where these things are happening a little bit even out into the international realm. So where is the data collected? Are there projects that are around the U.S. or is this focused more in just one area where you're trying to collect this data?

ZDENKA WILLIS: So these different scientists are actually collecting information in all of our U.S. waters. So the major challenge that we have is to synchronize the many tagging programs and improving data sharing to the broader ocean science community. And that's where IOOS comes in. With the broader science community behind us, we have become engaged and linking this to IOOS, we'll be able to provide the information more readily to state and federal officials who need it most.

Scientists are already collecting this data for their own research. But by bringing it together, we can make it available on the broader scale. We're also trying to bring together that biological data into this national system and that's always been referred to as the 'messy' data. So we're trying to bring it together in a way that's easy for everybody to use.

And the underpinning of IOOS is that integration. That technology in tagging is there, we are very supportive of those efforts, but really the ability to work with our folks at NOAA, USGS, and others is really where that power comes from in leveraging all of that technology.

HOST: And that's definitely no small task - being able to use the data that we get is a pretty important thing.

ZDENKA WILLIS: It sure is.

HOST: So is data downloaded once a day or is this a continuous real-time stream of data coming from these tags?

ZDENKA WILLIS: So it depends. If we're talking about satellite tags, when the animal is up towards the surface and we can communicate, then we can get that near real-time information. Some of the tags are archival in that we can't really recover the data until we recover the tag. Some of the acoustic tags we actually have boxes on the bottom of the ocean that's recording the information and we don't bring that back until we actually return the box. So it depends on the type of tag.

HOST: OK, thank you. What would you say is the greatest challenge with doing animal tagging?

ZDENKA WILLIS: Well, first our animals can be unpredictable, they don't exactly go where we need them to tag, and then getting out on the ocean is always unpredictable so we have to be able to match the weather conditions/safety with the location of the animals. Miniaturization of the packaging of the electronics is still a challenge - packaging them in a container that keeps seawater out at high pressure, has buoyancy and a radio transmitter for recovery, and is small enough to be attached to a dolphin without affecting swimming behavior. We have seen progress in the last decade, but there is work to be done.

Also, development of new sensors such as pH sensors to be added in response to concerns about the impact of ocean acidification and hypoxia on marine biological resources and the health of marine ecosystems.

Battery life. In most tags the electronics are rather small, much of the size of the tag is determined by the battery. A small battery means a short life and/or short transmission range or time. While larger tags last longer and transmit information better, they're also heavier and larger. So new methods of powering the tags would be a big improvement in size and longevity of the tag.

And finally, sustaining the funding for these kinds of efforts.

HOST: So Zdenka, given the technology aspect of a lot of the things we've talked about today, is animal tagging a relatively new research method?

ZDENKA WILLIS: Scientists started in about the 1990s, so it's been around for about 20 years. I think what's new is people's realization of how important this information really is and what it can tell us about behavior. And so, being able to bring that information forward to the public, that's the new and exciting piece of this.

HOST: And how long has NOAA been involved with the effort?

ZDENKA WILLIS: NOAA's really been involved since the beginning. NOAA is a leader in this ocean science technology.

HOST: Zdenka, my last question for you today - do you have any final closing words to leave our listeners with?

ZDENKA WILLIS: We like to say that this really is a perfect example of why IOOS is an important overarching network. We're able to see various researchers' data and make that information available from one place so you can see the bigger picture. It's kind of like the difference between seeing a regular movie and an IMAX 3-D movie, you just see more detail.

HOST: It's a great analogy Zdenka, thank you for that - a regular movie versus an IMAX 3-D movie, that's what it gives us. Thank you so much Zdenka for joining us today on Diving Deeper and discussing animal tagging with us. To learn more, please visit

That's all for today's show. Remember, if you have questions on this episode or the National Ocean Service in general, you can contact us at And if you're on social media, don't forget you can find us, it's usoceangov, on Facebook, Flickr, and YouTube; and we're noaaocean on Twitter. Please join us for our next episode in two weeks.