The settlers

CATAIN. You may see a fouled housing, but I see data.

Friends, in between spending days at sea on R/V Catapult looking at shipwrecks, I have another project that's at a very exciting stage. I've been collaborating with a group of engineers over the last year or so to develop a camera system that can photograph newly-settled juvenile invertebrates. The engineers kept calling it "LarvaeCam" as a working name (despite my insistence that it didn't photograph larvae), but I think I'm going to name it CATAIN - CAmera To Analyze INvertebrates. This name is also conveniently a nod to the nerd-tastic board game Settlers of Catan (because the camera photographs settlers, get it?).

A snail crawling on CATAIN. The light part is its foot, and
I think the skinny light part might be its radula.

CATAIN got its first test deployments this summer, and the results look very promising. Our major innovation was photographing the settlers from the underside, using the clear lexan end-cap of the housing as a fouling panel. That way, you don't have to worry about camera lens fouling - a common problem becomes a strength instead. Our first test showed snails crawling on the lens and laying egg cases, which was pretty cool. I had never seen a snail from the underside before, so it took me a good minute to figure out what I was looking at.

For the second test, we left CATAIN for about about a month under the WHOI pier, and by my count, it collected 7 species - a barnacle, 3 bryozoans, a polychaete, a spirorbid, and an ascidian. One of my collaborators stacked the images into a movie, and you can actually see the organisms arriving, growing, and in some cases, disappearing. That last part is the most exciting for me - CATAIN's original purpose was to measure post-settlement mortality in environments where it's not

One of the CATAIN images from our 1-month test. Edited
by Yogi Girdhar.

easy for a researcher to go collect samples every day. I wanted to know how many of the larvae that settle on the camera die within a few hours or days (studies in some environments suggest it can be as high as 99%). After seeing the images, I'm realizing we can also measure growth rates, overgrowth competition, and see if settlement of some species is tide-dependent, too.

I've handed off the images to my new graduate student, Kharis, who will analyze them to collect all the numerical data she can. I'm very excited to use this new tool!