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Saturday, December 11, 2010

Satellite Tagging of Southern Resident Killer Whales

With the endangered listing of the Southern Resident population of killer whales they have received even more attention from researchers to fill in the gaps in our knowledge about them and ensure they receive adequate protection. One of the first issues to come up was vessel regulations regarding boater behavior around the whales. There was a public comment period about this issue that received much attention, and a hearing in Friday Harbor back in October 2009. Originally we expected the new regulations to be announced for the 2010 whale-watching season, but the announcement was postponed and I imagine we will find out what NOAA has decided before the 2011 season is set to begin. Now, there is a public comment period open in regards to another issue: satellite tagging the Southern Resident Killer Whales.

Many people are surprised to learn that we don't know where this population of whales spends its time for much of the winter months. While their daily movements are monitored closely while they're in inland waters, as soon as they head out to the Pacific Ocean sightings are scarce with weeks or even months passing between encounters. We know the whales range over much of the outer coast from northern British Columbia to Monterey, California, but how far offshore they go, where their important feeding areas are, and how often they frequent different regions is for the most part unknown. It is important to learn where these whales are in the winter so the area designated as their critical habitat can be defined to give them more protection.

While long-term satellite tags have been used more widely on large cetaceans, a relatively non-invasive long-term tag for smaller cetaceans is a fairly new technological advancement. Suction cup tags have been placed on Southern Residents, but they typically stay on for a matter of hours rather than weeks. Recently satellite tags have been used more widely on small cetaceans, but there has been a hesitation before using them on this endangered group of whales to learn more about the risks involved. Earlier this year, Brad Hanson, one of the lead cetacean researchers in the region, applied for an amendment to his permit from NOAA that would allow him to deploy six satellite tags on Southern Residents.

This has raised several concerns about the public administration of whale populations. One of the biggest concerns people have is about the wounds caused by the tags, which contain a pair of titanium darts that embed more than 2.5 inches into the skin. The tags eventually fall off (11 transient killer whales have been tagged on the west coast since 2008, and the tags transmitted for anywhere from 16-94 days), but can leave open wounds and scars as evidenced by follow-up monitoring. Such wounds are potentially an entry point for disease, and with a population of fewer than 90 animals, the loss of even one animal is a huge impact.

It's important, I think, to consider that these animals receive similar injuries to their fins and bodies in their everyday life. This wound on the dorsal fin of K21 Cappuccino, as seen earlier in 2010, looks just as bad or worse than some of the post-tagging wounds:

I had to think long and hard about this issue, but I believe that the benefits of learning where these whales spend time in the winter outweighs the risk of tagging. Here's a copy of the public comments I submitted with some more details of my thoughts:

I support the proposed satellite tagging of Southern Resident killer whales as a means to gather important data that is currently lacking, particularly when it comes to designating the winter portion of the critical habitat for this endangered population of orcas. I understand this is the most feasible method to gather this data, and respect all of the precautions that are being taken. I think it is especially important to deploy the tags at the appropriate time of year to get the required data, and to monitor the tagged whales’ health to the best ability possible, both of which were indicated in the proposal. However, after reading the amendment request I found myself with the following questions:

1. Will the number of tags to be deployed (6) provide sufficient data to begin designating critical habitat for these whales? Satellite tag data was key in designating the critical habitat of Hawaii’s false killer whales, but 23 satellite tags were deployed on that population.

2. The request states: “The only alternative method for obtaining information on offshore movements is through boat-based photo-identification, which is severely limited in scope by sea conditions and range of small vessels.” At the Marine Naturalist’s Gear –Down in Friday Harbor on November 5, 2010 I learned from a talk given by Candice Emmons that acoustic detection of Southern Residents has been attempted via remote hydrophones along the outer coast since 2005 in addition to these boat-based surveys. What information has been learned through this technique and why isn’t this a sufficient method to determine the winter range of the Southern Residents?

3. When you are dealing with a small population size, which individuals will be targeted for potentially invasive research is a key issue. Even though the short- and long-term impacts of satellite tagging are deemed minimal, implanting tags is not a zero-risk operation and the appropriate individuals should be selected for deployment. I have questions regarding the individuals that are listed as candidates for tagging in Table 2. While post-reproductive females no longer play a direct role in increasing population size, they play a cultural role of undetermined importance to the community as a whole. With the loss of several of these older females in recent years, I would propose that the targeted females are of post-reproductive age, but perhaps not older than the age of 70 given the unknown importance of this small segment of the population. I have also heard that some of these older females have not been successfully biopsied or suction cup tagged, and if this is the case they may not be the most approachable whales for satellite tag deployment. Additionally, I think post-reproductive age females under 70 that have never been seen with a calf (such as K40) and reproductive age females that have not been seen with a calf for a decade or more should be the highest ranked candidates for tagging. Given the small population size and the limited number of breeding age males, I would also propose that no more than one male per pod be tagged.

4. Finally, I don’t feel that sufficient justification was given for the increase in suction cup tag deployment from 10 to 20. While the data gathered from these tags is interesting, this research is invasive and it has not been demonstrated here as being critical to filling the data gaps in our knowledge of this endangered population of whales. Unless such justification occurs, I don’t believe it is necessary to increase this type of tagging.

If you have your own thoughts or opinions on this issue I strongly encourage you to send in your own comments. You can read the federal register for the proposed amendment here. The modification request can be read in more detail on NOAA's site here, where under attachments you can also download a pdf of the amendment proposal (the second of the three downloads) submitted by Brad Hanson, which I found to be the most informative read. The public comment period is open until December 23rd, and you can submit your comments via e-mail to They request that you include File No. 781-1824 in the subject line.

This December 10th article in the Victoria Times Colonist and this December 5th article in the Kitsap Sun also provide you with some more good information.

1 comment:

Howard Garrett said...

Monika, thanks. This is a thoughtful and informed look at the issue. There are some conflicting values to consider here. I like good science, especially if it may result in expanding the designated critical habitat and possibly protect the orcas from Navy sonars. But on the other hand even a slight insult or disturbance to the So. Residents seems like too much, and the data gained won't help much to restore salmon habitat.