What It Takes To Rule The (Marine) World

Christie Wilcox in Science Sushi:

Fifty-five years ago, Jack Briggs determined there were 107 fish species with a trait most fish cannot boast: a global distribution. These circumtropicalspecies can be found in all tropical oceans, having found their way around the land masses which split the seas (at least often enough to persist as a single species). Now, in a publication for the journal Fish and Fisheries, Briggs has teamed up with Michelle Gaither, a postdoctoral research associate at Durham University, UK, and colleagues from the University of Hawaii and the California Academy of Sciences to update the half-century-old list. Of the over 20,000 marine fish species, a mere 284 span the seas to maintain a global distribution.

The team was able to re-evaluate Briggs’ original list thanks to breakthroughs in DNA sequencing that have occurred over the past 50 years. By looking at genetic sequences rather than just morphological differences, scientists are able to not only separate similar looking species, they are able to determine whether a single species is split into distinct populations or whether individuals are able to travel vast distances to keep disparate areas connected. Thanks to genetic data, nineteen of the original 107 have since been shown to be complexes of multiple species or not to make it around the globe, while 196 new species have joined the 1% club.

More here.