No Damsel in Distress

By Abigail J. Lynch, USGS

I’m not sure how many people can trace their career origin back to a specific instance, but I can.

I was sitting in a concrete block of a building, an old military installation that had been retrofitted to be an auditorium-style classroom. Students were scattered across the carpeted steps of the room. It was hard to tell if the carpet was damp or just dingy from years of exposure to the salty sea air. There was a big chalkboard in front of us; the professor started a list of marine organisms. We would draw numbers, we were told, to pick an organism from the list on the board. Our choice would be the focus of our independent research projects.

I was an undergraduate student in the long-running University of Virginia Marine Biology Study Abroad program. We were on San Salvador, a tiny, 65-square mile island at the easternmost edge of the Bahamas. San Sal, purportedly, was the first glimpse Christopher Columbus had of the new world.

Sitting in that auditorium, we’d been through about half of our program, with lectures in the morning and evening and snorkeling most of the day. We soaked up everything we could, hoping our brains could hold as much information as a sea sponge could hold water. Now it was time for us to take the science training-wheels off and apply all that we had learned to our very own research projects.

Excited and nervous, I drew my number—a woefully high number—oh no!! I had made the mistake of setting my hopes on studying the Dusky Damselfish Stegastes adustus—by far, the coolest thing on the list—it would surely be selected by the time my number was called.

Amid a rainbow of colorful reef fish, this drab little fish stands out. On one of our first snorkeling trips, I noticed these fish on the reef bed nibbling on algae from a well-defined patch of reef, which they appeared to be guarding. Turns out, they were. Dusky Damsels are essentially algal gardeners. In tending their territories, Dusky Damsels have a measurable effect on the benthic community. They foster highly productive gardens with higher biomass and greater algal diversity than at locations outside their territories. By defending their gardens from other herbivores, they ensure a limitless food source for themselves (their consumption never exceeds primary production).

As a curious snorkeler, I found out fast that the territoriality of Dusky Damsels is pretty astounding—when I dove down to take a look at one of these garden plots, I got an assertive tap on the mask from the garden’s owner! I was shocked and charmed all at once. This was no damsel in distress. This plucky little fish had me hooked.