Kludgey science

Over the past couple of days we have been scavenging bits from Jon's piles of old research equipment at the Charles Darwin research station for use in our experiments this summer. If you've worked somewhere for 10 years I guess you accumulate lots of stuff, particularly if you're a macro-ecologist and like doing large scale things. Leslie's project aims to create a demographic model for an ecologically important predatory snail species, Hexaplex, and compare how its populations behave in areas where it is fished, versus areas where fishing is prohibited. To figure out the different parameters of the model (e.g. growth rates, mortality rates for different sizes of snail), she needs to tag a bunch of Hexaplex in their natural habitat and track them over time. So we dug into Jon's stash of barnacle recruitment plates from 2003 (complete with 8 year old barnacle tests) to find tags she can use.

Some scraping with screwdrivers and a few good rinses gave us slightly over 200 tags, all ready to be Z-sparred* onto Hexaplex shells.

Leslie is using plastic calipers for her measurements of Hexaplex, but the starfish I will be studying are a little too big for that. The bigger ones, Pentaceraster and Mithroidia, can have arms up to 17cm long. So I made my own measuring instruments out of an old transect tape, cable ties and old fishing weights. I have no idea what the weights were used for before (we pulled them out of an old box and they were all cable-tied together in fives) and I'm pretty sure that transect tape was hopelessly tangled long before I even knew what an echinoderm** was, but the cable ties were the only new component of my brand new starfish measuring tapes.

And while I had the fishing weights and cable ties on hand, I made a little upgrade to the underwater housing for my camera. The housing is positively buoyant (=it is floaty) when I dive, which is really annoying because it floats up and smacks me in the face when I'm not holding on to it. Canon makes a weight system for the housing, but it costs a whopping $26 for what is essentially a screw and a few pieces of metal. So I cable-tied a fishing weight to the bottom of the housing instead. We'll see how well that works tomorrow, when we do our first Galapagos dive (!!!)


* Z-spar is the name of an underwater epoxy. I think it is probably counted among the holy trinity of field marine ecology: PVC, cable ties and Z-spar.
** Echinoderm means "spiny-skinned" and refers to the group of animals that includes starfish (my study organisms), sea urchins and sea cucumbers.