"Some of the sampling sites are about 22,000 kilometers apart, so essentially two-thirds of the globe," says Reece. "Yet you find the same alleles in South Africa as you do in Panama."
"The only way to get shared genetic material across these distances," says Reece, "is through gene flow." The leptocephali, in other words, are efficiently ferrying genes from one population to the next, keeping the gene pool well stirred.
Several other reef fishes are also known to have highly dispersive pelagic stages. However, even these species show genetic partitions at major biogeographic barriers. The moray eels are in a class unto themselves, the champion dispersers.
Although the phylogeographic survey answered some questions, it raised others.
If both species of eel are able to maintain genetic connectivity across the entire ocean basin, how did the species arise in the first place?
And not just these two species. Altogether there are 150 species of moray eel in the Indo-Pacific, including the giant, ribbon, snowflake, zebra, dragon, pink-lipped and freckled morays, the slenderjaw, hookjaw, viper, vagrant, lipspot and enigmatic eels . . . and many more.
When and how did they form separate species if their larvae make them nearly impervious to geographic isolation?
To further complicate things, says Reece, many of eel species share habitat, share distributions and share prey items. In most groups, he says, when that happens one species outcompetes the other and the loser disappears. The same rules don't seem to apply in the morays and nobody knows why.
In other words, he may have found his postdoctoral as well as his doctoral research lurking under that ledge.
|Contact: Diana Lutz|
Washington University in St. Louis