Open Water Live!

I am going to let Curt Storlazzi, my dive buddy on some dive's yesterday to check some oceanographic instrumentation, describe it:

"So today we were diving off Santa Cruz today to check on some oceanographic moorings and a tripod we deployed yesterday. As my dive buddy Ian Miller and I get to the surface, our comrades (Jamie Grover, our boat captain and Amy Draut, another diver) on the boat are swinging it around trying to follow what Jamie is saying is a mola mola (sunfish). As the boat turns, Ian and I see a fin that looks nothing like a mola mola but rather something a little more threatening. Jamie and Amy are pretty interested in it, and Ian and I are sort of laughing as we get out of the water and into the boat. We swing the boat around and what do we see? Check out the attached photos.

I would like to say it was huge and threatening, and from eye level in the water it's fin sure looked it, but it was just a baby....that was probably thinking, "In a year, you're TOAST!""

Despite our initial excitement that we were watching a juvenile white shark glide effortlessly next to our boat, I've come to the conclusion that this is a salmon shark. Still, its the first time I've seen a true pelagic shark in the wild (and shared space in the water with one), and it was exhilarating.

Oh, How They Move

Slowly I am pulling together my PIT tag information and mapping cobble movement on the beach. Today, with the help of Josh Logan, I was able to partially overcome my handicap with various software and figure out how to put this information together. What you see here is as hot off of the press as it comes. This image covers two surveys on August 4th (red triangles) and August 12, 2008 (white triangles), with a sample of 32 tagged rocks released on August 2nd. So what is the big deal? Well, this two week period was relatively quiet. Waves were very small (definitely unsurfable). Despite this, stuff was moving on the order of 10 meters or more per day. Remember, these are rocks, not sand. Also, we can clearly document a VERY uni-directional pattern of rock transport on this section of beach. Its only a start, but being able to see SOME progress is a very nice thing in my day.

Ian

PIT tags are everywhere!

They really are. I read this morning about a company that uses PIT-tags in curb-side recycling containers to track recycling rates, and distributes rewards based on a households recycling rate. Pretty bright. If I had thought of that I might be rich right now. But instead I put them into rocks. So I am not rich.

I've spent the past few days starting to analyze data on cobble movements on the Elwha shoreline that we collected using PIT_tagged rocks. All told, we tagged 224 rocks by drilling a 1/4" hole in the rock and epoxying (is that a verb? Like facebooking?) the tag in place. The tagged rocks were placed at three different locations (shown on the groovy map as small, barely discernible black dots) and then we mapped and surveyed the movements of the tags using a reader and GPS unit over periods of days, weeks and months.

The re-find process involved walking the beach with a reader unit (looks just like the crazy old guys you see early on Monday morning down at Main Beach in Santa Cruz, looking for quarters and lost rings in the sand). When the reader antennae and a PIT tag come into proximity (usually about 1 meter) the reader squeals and records the tags ID. We can then GPS the location of the rock using its ID as a Waypoint in the GPS.

The movements surprised me. In some cases, I found that relatively large material, that I hadn't expected to move at all during the summer, was moving 15 to 20 m per day. Our next step is to try to survey movements around a storm event.

Ian