Moray Eels Are Everywhere and There Is One Over Your Shoulder Right Now!

Evolution 2009
What is a marine biologist doing in Idaho?  That is the question I have heard a lot lately from friends and family.  The Evolution 2009 meeting is taking place right now in Moscow, Idaho.  And well, deep-sea biologists are evolutionary biologists too dammit!

Thinking of Rick Macpherson I could not avoid attending Joshua S. Reece’s talk “Moray Eels: A Phylogenetic and Phlyogeographic Enigma”.  Joshua presented on his dissertation work at Washington University in St. Louis that had the rather lofty goals of uncovering “Why are there so many species of moral eels?”  The 200 moray eels are distributed globally, a concept nicely illustrated by Reece just showing a slide of the globe. Pick just about any part of the wet and salty earth and there will be a moray eel ready to consume your face.  About 150 morays are found in the Indo-Pacific and are the focus of Reece’s work.  The enigma is that moray species all do about the same thing ecologically and are morphologically very similar.

Now according to the competitive exclusion principle, two species doing the same thing in the environment, e.g. utilizing the same food source or habitat type, will compete with one another.  Assuming one species is competitively superior and monopolizes the resource, it will drive the other to extinction.  Now you can begin to appreciate the conundrum that is moray eels.

Reece’s approach to this question is to examine what limits and shapes species ranges of eels.  Morays have extraordinary larvae, the Leptocephalus, that is an enigma in itself.  The larvae contain no digestive track and no yolk but can maintain themselves in the water column from 6-24 months.  It is thought that they might do this by absorbing amino acids directly through their skin.  This amazing dispersal ability combined with the lack of any perceived barriers to this dispersal in the Pacific leads to the prediction that most morays would possess very broad geographic ranges.  Indeed, that is exactly what Reece finds in two species using the tools from both classical biogeography and modern phylogenetics, i.e. phylobiogeography.  Perhaps, the most interesting finding is that 94% of all the genetic variation found in individuals distributed throughout the Pacific in the two species can be found in a single population!

If anybody reading this is attending the meeting, come find me at the National Evolutionary Synthesis Center’s booth or at my talk Monday morning at 9:30 in the Law School Auditorium.  I will be talking on the linakges of biodiversity and body size in Metazoans based on this paper.

Dr. M (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (, a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.

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