Yesterday I wrote about re-encountering some old “friends” on the deep reefs here in Pohnpei. Today I was reunited with another.  In this case, however, perhaps the word “nemesis” is more apt than “friend” to describe this particular relationship. Among the fishes that we often find on deep reefs, members of the genus Plectanthias (perchlets). I have many specimens of several new species collected from various deep coral reefs around the Pacific, but one particularly colorful one has eluded me for years.  I first saw it more than ten years ago at a depth of about 350 feet (105 meters) in Fiji.  A few years later I was able to get some video clips of it, but I never managed to find any more individuals of this particular species during my travels elsewhere in the Pacific.  Until today, that is.

A comparison of what appears to be the same new species of Plectranthias from Pohnpei (left) and Fiji (right). Photos: Richard Pyle.

A comparison of what appears to be the same new species of Plectranthias from Pohnpei (left) and Fiji (right). Photos: Richard Pyle.

Today we selected a spot further south along the western coast of Pohnpei. Brian, Rob, Sonia and I started our dive with the usual equipment check in shallow water prior to starting our deep descent.  Both Rob and Brian needed to make some adjustments to their rebreathers, so Sonia and I headed down while they returned to the boat.  We followed a gully down the usual profile (drop-off to about 150 ft/65 m, followed by a steep slope), and by the time we got to 350 feet (105 meters) there didn’t appear to be much in the way of interesting habitat (at least not for fishes — as usual, Sonia was surrounded by all sorts of spectacular gorgonians).  I found a few holes in the rocky bottom and started scouting for Belonoperca pylei (which Brian had seen yesterday at about the same depth). I caught a glimpse of a fish with roughly the right colors, but on closer inspection I saw that it was the same Plectranthias that had eluded capture in Fiji all those years ago! This time I successfully captured two specimens (after getting some video of one of them), then signaled to Sonia that it was time to head up (she never seems to have enough time to gather all the interesting gorgonians specimens she sees down there — she’s like a kid in a candy store!). On the way back up, I also collected two specimens of what we’ve been calling “Chromis cf. brevirostris”. On closer inspection, it seems we can remove the “cf.”, as these definitely appear to be C. brevirostris.  Perhaps DNA sequencing will shed some insight. Brian also had a successful deep dive, collecting some interesting species (which I’ll leave to him to describe in more detail in another post).

A variation of Chromis brevirostris, lacking any yellow in the dorsal area.  I also collected a "typical" C. brevirostirs (with yellow) at the same location and depth. This may or may not prove to be a distinct species. Photo: Richard Pyle.

A variation of Chromis brevirostris, lacking any yellow in the dorsal area. I also collected a “typical” C. brevirostirs (with yellow) at the same location and depth. This may or may not prove to be a distinct species. Photo: Richard Pyle.

Tomorrow we will take the day off to repair some equipment, take a break from deep diving, get some rest, and also pick up John Earle from the airport.