Shining a light on deep-sea biodiversity

Photo: Burke Museum
Photo: Burke Museum
October 29, 2015 | Theodore Pietsch

I went to grad school intending to be a herpetologist. During my first summer they gave me a job sorting five-gallon buckets of dead fish that were trawled up by a deep-water research vessel. And all of a sudden I saw these deep-sea anglerfishes. Big mouths, huge teeth, giant stomachs that expand—they can eat something bigger than themselves! Not to mention the parasitic reproduction. These are amazing things to a kid who grew up in southern Michigan. I completely forgot about snakes.

One of the things I tell my students is that the little things can be turning points. One conversation or experience can steer you in a different direction and be incredibly important in your life.

When I started out, everybody said, “Don’t start working on anglerfishes. They’re so rare, and they live really, really deep.” And it’s true, you go out on ships and try to find these things, and hope one might be alive, but more often than not you come up empty handed. That’s why you have to look at museum collections. People say, “Are you going to travel when you retire?” But that’s what ichthyologists do: tour the world to see collections, to sit and look at what’s in jars.

In late ’60s there were about 400 named anglerfishes. But when I looked closely, I realized a lot of people had described the same thing over and over again. Nobody realized how easy they were to understand. They have a little luring apparatus on the tip of their snout. With the deepsea anglerfishes, it’s species-specific—they are all different shapes, they have different arrangements of filaments and pigment patterns. In my dissertation, I narrowed it down to 130 species; there are 160 now.

We know a lot more than we used to, but there are so many more things someone could look at. No one has ever seen the chromosomes of these things—nobody knows whether they actually have two sets. People hypothesize that some anglerfishes are reproducing parthenogenetically— they’re cloning. That would be a really neat thing to explore.

I realized a lot of people had described the same thing over and over again. Nobody realized how easy they were to understand.
Ted Pietsch, Burke Museum Curator of Fishes

Ted Pietsch retired in July after 37 years as Burke Museum curator of fishes and professor in the UW School of Aquatic and Fishery Sciences. His work on anglerfishes is described in “Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea” (University of California Press, 2009).

Excerpted from "In Our Own Words," the Burke Museum 2015 Annual Report.