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expeditions/ 2005 RAMP/9_23_05
- Defender of the reef
David Nichols, State of Hawaii, DLNR, HIHWNMS
One of the two new genus
of coral guard crabs that have been recorded by Scott Godwin
of Bishop Museum. Photo by
We have finished with Maro Reef and are transiting to Pearl
and Hermes Atoll today. Transit days give the scientists time
to organize and evaluate some of the data and organisms that
have been collected. Invertebrate specialist Scott Godwin
of Bishop Museum spends most of his free time in the vessel’s
wet lab analyzing some of the specimens he and assistant,
Holly Bolick collect during an REA dive.
he shows me a coral guard crab (Family: Trapeziidae).
These crabs live in association with various species of branching
coral throughout tropical coral reef systems. Mated pairs
actually live deep within the coral branches and are completely
dependent on the coral for food and shelter. In fact, these
crabs use their massive claws to ward off intruders that threaten
their host coral. If a coral-eating predator (i.e. crown-of-thorns
starfish) settles on their coral head, then the guard crab
will begin to snip at its tube feet causing it to retreat.
They claim that even a diver can get a pinch if he places
his hand over a branch of coral with these crabs.
are twelve genera of coral guard crab throughout the world
and only one genera, Trapezia, has ever been recorded
from the Hawaiian Archipelago. Two genera and species of coral
guard crabs have been recorded for the first time from the
Hawaiian Islands during this cruise by Scott from Maro Reef
and French Frigate Shoals. These species, Tetralia glaberrima
and Tetraloides heterodactyla, represent two new
Hawaiian Archipelago records for the family Trapeziidae.
These two species are obligate symbionts to the coral genus
Acropora and the Northwestern Hawaiian Islands is the only
location in the Hawaiian Archipelago in which this coral exists.
we have a crab (so small you could carry it around on a dime)
protecting his own little piece of coral. The picturesque
Tetralia glaberrima gets my vote for the “unofficial
NWHI poster critter”. The coral guard crab – defender
of the reef!
Holly Bolick of Bishop Museum surveys
the coral at Maro Reef
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