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THOMPSON'S SURGEONFISH
Acanthurus thompsoni (Fowler, 1923)
This small plankton-eating surgeonfish
occurs in midwater either singly or in small groups, and occasionally
in aggregations of hundreds. It is uniformly blue-gray to dark brown,
almost black. There is a single black spot above the base of the
crescent-shape tail. The species is perhaps most common along the
Big Island's Kona Coast, but can be seen at most dive sites. Juveniles
occur in beds of Finger Coral (Porites compressa). The name
honors John W. Thompson, a technician and artist at the Bishop Museum
from 1901 to 1928. (Four Hawaiian fishes are named for Thompson,
two of them endemic. He must have been quite a guy!) Thompson's
Surgeonfish grows to 10 in. but is usually smaller. Indo-Pacific.
Acanthurus thompsoni, juvenlie -Honaunau, Big Island
Two species or one?
The fish now called Acanthurus thompsoni occurs from East
Africa to Hawai`i. In Hawaiian waters its tail fin is dark, the
same color as the body. Everywhere else, however, its tail fin is
bright white. The body also tends to be darker. Might two species
be involved? Other than color ,there seem to be no physical differences
between the two. Perhaps the issue could be resolved by DNA. If
there are two species, the Hawaiian one will retain the name
thompsoni because it was originally described and named from
Hawai`i in 1923 (Hawai`i is its "type locality"). It will
be considered endemic. Its cousins outside the Islands will probably
be called Acanthurus philippinus, a name given in 1927 to
white-tailed specimens obtained in the Philippines. At present,
A. philippinus is considered a "junior synonym"
of A. thompsoni.
Acanthurus thompsoni - Majuro, Marshall Islands
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