Thousands of species inhabit polar waters

A survey performed as part of the massive Census of Marine Life effort reports thousands of species of fish and (mainly) invertebrates in the waters around the poles. This area was once thought to be a biological desert. It's anything but. Hundreds of new species, yet to be formally described, are included in this haul. Strangely, an estimated 235 species appear at both poles - but nowhere in between. Their presence is spawning (no pun intended) new theories and studies in an effort to understand how such animals migrate over time to colonize new regions.