Master's student at McGill University (Montreal, Quebec, Canada) and is studying the divergence in electric signals across populations of knife fish. He needed to collect 40 or so Brachyhypopomus occidentalis from a shallow stream and then record their signals.
We drove to Parque Nacional Soberania, which is about 45 minutes north of Panama City. It's famous for bird-watching Once we got to the park, we took the most ridiculous roads and I thought the car was going to fall apart. Every ten or twenty seconds we'd hit a hole or bump that made us fly a few inches up from our seats. It took significant physical effort to stay upright. Along this route we also saw one of Alex's favorite flowers, "the hot lips, colloquially referred to as "labios de Chomba," which roughly translates to "lips of black women." According to Rigo, who works in the STRI freshwater fish collection and was driving the truck, Chomba is a local name for African women.
Labios de Chomba flower. Image taken from Google images.
The collection process was really cool. We splashed through ankle-to-thigh-deep, cool and extremely refreshing water throwing down a rod with electrodes attached to either end. When in the water, the signals from the fish are conducted through the electrodes to an amplifier which converts the energy to audible sound. The sound came out as intermittent pulses which were of a lower pitch for larger fish. When we heard some pulses, we'd wave the rod around just under the surface, listening for where it was the loudest to pinpoint the location of the fish. The fish don't tend to swim away when we do this, so it is easy to find them this way. To catch them we'd use a large net to scoop up the water and top layer of substrate, then check to see what we got. I wish I had pictures, but no one brought a camera!
After about an hour of this, we caught about 30 fish and decided it was time for lunch. We put away some field equipment while Alex prepared what he brought for us, which was the epitome of field food: tortillas, re-fried beans served out of the can, a red pepper sliced with a swiss army knife, a pouch of tomato sauce, and some shredded cheese. I liked it, but it was not so appealing to Rigo, who nearly preferred hunger to these "tacos de Alex."
We finished eating and relaxed while Alex prepared the electric recording apparatus. Cassie and I tried to help, but apparently we were inconceivably sleep-deprived because after about 20 minutes we fell asleep on a bed of jagged rocks and slept for nearly an hour. When we awoke, Alex was still going so we helped him finish. Basically we stuck each fish inside a tube in a cooler of water. At each end of the cooler were wires which would record the fishes' constant electric signals. As Alex tallied up the fish, he taught us his efficient way of tallying, which utilizes dots and boxes instead of just lines.
This image shows how to count from 1 to 10. I think it is much more
organized and easier to read than the traditional tallying method.
Once we finished recording and tallying, we headed out. It was only the late afternoon, but by now Alex was so tired he was "fishing" the whole way home in the car--by "fishing," or "pescando," as Rigo says, I mean his head was bobbing in and out of sleep as a bobber on a popular fishing line. I'm really glad we got to help him, and I hope the data we got helps with his project!
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