Sunday, September 28, 2008

A new Species of Giant Grouper?

A recent scientific blog is featuring this video of Ratu Rua -pictured here by Michael Aw- one of our Giant Groupers, claiming that it is a newly discovered species, the "Pacific Goliath Grouper", a sister species of the critically endangered Atlantic Ocean former "Jewfish", and now Goliath Grouper Epinephelus itajara.

Well, maybe there is indeed such a distinct species inhabiting the Eastern Pacific. After Andrea Marshall's stunning discovery of a second Manta Ray, anything is possible.
But Taxonomy is often a matter of judgment and Scientists can generally be divided into "Lumpers" and "Splitters". The latter are often newbies lacking a track record of bona fide descriptions and are eager to finally put their name to a new discovery. I remain skeptical.

When it comes to Sharks, one famous -or infamous- such case was the attempt to split the Grey Reef Shark, Carcharhinus amblyrhinchos into Carcharhinus menisorrah (or proper Grey Reef) and Carcharhinus wheeleri (or "Short-nosed Blacktail Shark) in the 70ies, this based on the observation that the latter Indian Ocean Grey Reefs have a slight white edging to their first dorsal fin and apparently never engage in the typical agonistic display of the Grey Reefies in the Pacific.
It was finally resolved that they are all but one species and in fact, you can see both color morphs on Shark Reef.

But back to the grouper.
A Goliath Grouper looks like this.
It was filmed in Fernando de Noronha, thus in the Atlantic Ocean, but apparently, the "new" Grouper looks identical in body form and markings , the classical case of a Cryptic Species Complex.

In fact, the new Pacific "species" has been named Epinephelus quinquefasciatus, this in reference to its five color bands which are identical to those of the Goliath Grouper above.

Ratu Rua looks nothing like it.
She is uniformly mottled dark with a slight light edging to her fins, a reminder of the much more striking edging when subadult (the juveniles are yellow with irregular black bars).
Like our other three large groupers, she is clearly Epinephelus lanceolatus, the Giant or Queensland Grouper.

Want to know more?
Check out this page from our latest fish count in February!

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