Fishing Day - Jan 2014

It's 730 am. You are crouched low over a mountain stream, the cool fresh water bubbling over many colored small stones in the stream bed. Your eyes flick carefully over the water, searching, two butterfly nets held at the ready in your outstretched arms. A hummingbird flutters in the bell of a large flower unnoticed overhead, and a blue butterfly the size of your open hands flies over the stream. A tropical bat hunts in daylight, circling over the water and snatching bugs from the air. You'll see these things in a minute though - right now you too are hunting.

Work is well underway. Each full period (one month) of data collection for the mark-recapture study, we fish out the complete population of guppies in designated sections of streams running down the mountains of Trinidad's northern range. We schedule a fishing day, a lab day, and a release day to return the guppies from exactly whence they came. On the fourth day we move on to and start fishing the next stream. Lather, rinse, repeat for all four focal streams. This is called the Recap.

There! Darting from the cover of a rock ledge a small guppy darts out into the open. Even now, after only a few days of fishing, you have a good guess that it's a female with a red tattoo mark on her back. You carefully swish the nets into place under the water.

“Gotcha!” Pulling the nets from the water, guppy caught inside, you are triumphant. Double checking the sex you put her in one of the two white five gallon buckets you and your fishing share, separating the fish by sex to cut out artificially introduced mating. A large leaf floating on the surface denotes the female bucket. You stretch out your shoulders, notice the hummingbird, bat, and butterfly with delight, and return your nets to the water. One down. Four hundred guppies to go.

There are six of you fishing in teams of two, steadily making your way riffle and pool down the length of the stream, working toward each other. Even with hundreds of guppies left to catch, you'll have time to relax together over peanut butter and jelly sandwiches and lay back on heavy hiking bags, empty now of medicated water bottles that will bear the fish back to the lab. Since you started out at sunrise and fished well all day, the hike up the trail to the truck and the drive home will be mid-afternoon and everyone will be home, neatly labeled guppies set up in tanks in the lab for the night, well before dark.

There's a lab day tomorrow to process the guppies and collect the data that will be sent back to U- C- R-, and eventually form up into patterns which will, hopefully, reveal something meaningful about evolution and ecology. Over the last decades, the data from Trinidad have been fruitful.

Tomorrow will be fun in its own way, indoors (if you can count a room filled with natural light through a wall of open windows "indoors"), but tonight you are done. Sitting around together on the open front porch on well-worn couches and hammocks, the guppy team feels good.