How to measure a harbor seal without actually measuring the harbor seal

Seeing as I’m still waiting on the final confirmation from the permit office, I’ve decided to use my “spare time”* to test out as much equipment as possible and get as accustomed to my field site as possible.

*I use this phrase loosely, because really when is there ever a moment that a grad student has nothing to do…

Most of the equipment I’m using this summer is fairly basic – I’ve got the usual hydrophone/recorder set-up and a standard GPS unit and laser rangefinder. I also bought myself a GoPro, because what kind of marine research project would this be without a GoPro?!  And I just have to say, the GoPro camera is by far the least intuitive piece of equipment I have this summer. It took an embarrassing amount of time just to figure out how to open the waterproof case. It also took a bit of practice to figure out the difference between the video mode and the photo mode. I gave a great explanation of my field site to the GoPro camera on photo mode.

In-depth explanation of Elkhorn Slough given to a GoPro that was not recording.
(Photo(<-haha): L. Matthews)

While there was a definite learning curve with the GoPro, there was no real assembly required. There are a few pieces of equipment, however, with which I’ve chosen to get a little creative. Most notably is the equipment I’ve designed to collect morphometric data on hauled out harbor seals. Morphometrics is a fancy word that basically means, “let’s measure how big that thing is.” This is useful data for bioacousticians who are interested in seeing if size differences between individuals carry over into the vocal differences between individuals. I happen to be one of those bioacousticians.

After digging a bit through the literature, and after some helpful direction from my advisor (paraphrased email: “Leanna, read this very specific paper that outlines exactly what you want to do”), I landed on a paper by Webster et al**. In this paper they explain how they mounted a pair of lasers to a camera, took pictures with the camera, and used the dots from the lasers to make post-hoc measurements of Hector's dolphin dorsal fins. Basically, if you know how far apart the lasers are, and if you know how far away the animal is, then you know how far apart the laser dots are in the picture. Plug this into some photo analysis software, and you can make all sorts of measurements! I took this idea, ran with it, bought some lasers, and started taking pictures.

Using lasers to measure dorsal fins (Webster et al.)

For my set-up, I used hose clamps, zip ties, super glue, and a PVC pipe to jerry-rig a mount for my two lasers. I also placed a bolt in the middle of the lasers so I could screw it into the tripod mount of my camera. There were days of finagling with the lasers to keep them in the camera’s viewfinder, but as of now they are securely fastened to the PVC pipe and are ready to be used for photographing harbor seals! I’m planning on making as many measurements of individual seals as possible, and hopefully I’ll be able to do some weight estimation with these measurements as well. This is a great way to collect data on wild animals without disturbing them. It worked for Hector's dolphins, so now we just need to wait and see if it works for harbor seals!

The laser set-up!  (Photo: L. Matthews)

**Webster, T., S. Dawson, and E. Slooten. "A simple laser photogrammetry technique for measuring Hector's dolphins (Cephalorhynchus hectori) in the field." Marine Mammal Science 26.2 (2010): 296-308.

FUN SCIENCE FACT #38: Fleas can jump 130x their height.  I'm 5'4" and my max vertical doesn't even come close to 693', so mad props to you, little flea.  Those are quite the ups you've got there.

A Lesson in Patience

Take a poll of a hundred marine mammal biologists and chances are that not a single one will tell you that studying marine mammals is easy.  One thing I’ve learned first hand about marine mammal research is that it takes a lot of people and a lot of paperwork to get a project going.  And one thing I’ve currently been dealing with is permitting. 

Now, let me just say that permits exist for VERY good reasons – marine mammals need these extra layers of protection when it comes to research.  And honestly, I don’t mind filling out permit modification requests and typing up protocols to send to the marine mammal head honchos for approval.  However, it appears that maybe I underestimated the timetable associated with permit modification requests and protocol approvals.  Oopsie. 

I made the trip from Syracuse to California about three weeks ago with every intention of starting data collection on April 15th.  This year, the plan was to go out to Elkhorn Slough (a narrow inlet in Monterey Bay), make underwater recordings of individual male harbor seal vocalizations, and take pictures of hauled out males to do some morphometrics.
  

Harbor Seals in Elkhorn Slough, CA (Photo: L. Matthews)

Luckily, over this past year, I’ve been able to team up with Jim Harvey at Moss Landing Marine Lab to be added as a co-investigator on his existing harbor seal permit.  Jim Harvey is basically THE go-to guy when it comes to west coast harbor seal research.  We thought that we’d gotten in all the necessary paperwork on time for my anticipated start date, but it turns out that there’s been a surge of permit applications, the permit office is a bit overwhelmed, and ours isn’t exactly at the top of the list.  It’s currently April 25th and I’ve yet to collect any data.  *sigh*  So much for that April 15th start date. 

In the meantime, I’ll play with my equipment and scope out my field site and make every possible preparation for data collection so that when I get the green light, I’ll be all set.  From what I’ve read and from what people have told me, the males vocalize through the end of May.  Seems like I’ve still got a good chunk of time to get a good chunk of data.  

So yeah, it’s definitely not easy – I knew this from the beginning.  But it’s definitely going to be worth it.  Can’t wait to get out there and make some recordings!  Any day now, I’m sure.  Fingers crossed. 

Cute little harbor seal face (Photo: L. Matthews)

FUN SCIENCE FACT #37:  The Challenger Deep is the lowest point on Earth.  Located in the Marianas Trench in the western Pacific, the Challenger Deep is approximately 10,916 m (35,814 ft) deep.  That's like putting Mt. Everest underwater and then still having another mile over water on top of it.  Maybe if you stacked like nine Empire State Buildings on top of each other you'd hit the surface.  

Photo: The Apricity