Nano Gobies

Savalia savaglia, formerly known as
Gerardia savaglia, a deepwater species
photographed by NOAA’s Hawai’i Undersea
Research Laboratory.
have a dry weight of approximately 440 billion pounds
(129 metric tons). Taking into account the annual mean
water temperature, the core skeletal density, and published
upward growth rates of about 0.4 inch (1 cm)
per year for massive Porites, this giant was estimated to
be between 360 and 800 years old, although there are
enough fudge factors built into the calculations that it
could be considerably older. Similar, and possibly older,
Porites colonies have been described from Taiwan; however,
because they are significantly damaged, their age
determinations are somewhat questionable.
Although it certainly is the case with Porites, it doesn’t
necessarily follow that other old stony coral colonies are
huge. Small individuals with very slow growth rates undoubtedly
exist. Nor does it necessarily follow that the
most massive colonies are the oldest of the scleractinia.
Individuals of very old branching species, such as staghorn
Acropora, may well exist but be indistinguishable
from young individuals due to the pattern of fragmentation
and regrowth exhibited by these species. Growth
rates of Acropora cervicornis in its heyday were as much
as 10 inches (25 cm) per year in elongation. These corals
propagated and spread primarily by fragmentation.
In other words, their whole physiological growth pattern
precluded colonies that were large and old. If these acroporids
had a philosophy of growth, it would be: “Live
Fast, Break Young, Grow Everywhere, Repeat as Necessary.”
The possibilities for growth patterns resulting in
very old, shallow-water, tropical coral reef corals appear
almost endless, but much more work to determine ages
must be done.
STONED IN THE DEEPS
Both solitary and colonial stony corals that are more
than a century old have been found in cold deep-water
regions. A large, solitary cup coral, Desmophyllum cristagalli,
has fist-sized polyps reaching
about 4 inches (10 cm) in diameter.
Specimens of D. cristagalli over 200
years old have been found throughout
the world’s oceans at depths from
about 328 feet (100 m) to over 2.5
miles (4000 m).
Colonial stony corals, such as
Enallopsammia rostrata and various
Lophelia species, have also been found
together with D. cristagalli throughout
the world in similar depths. Although
smaller, nowhere near as robust, and
often white, E. rostrata colonies bear
a passing resemblance to the large, greenish, branching
Tubastraea micrantha found commonly in shallow
waters in the Indo-Pacific. Individuals of many E.
rostrata colonies have been determined to be between
200 and 600 years old.
Some Lophelia colonies are bizarre-looking,
growing into three-dimensional meshes over 10
feet (3 m) high that somewhat resemble the skeletons
of geodesic domes, with the 1.2-inch (3-
cm) diameter polyps being found at the points
where various branches connect. Smaller Lophelia
species, under 3.25 feet (1 m) high, often
contribute the majority of the structure in many
deep-water reefs. Lophelia specimens have been
commonly found to be in excess of a century old,
and many samples are older than 300 years. Although
as old as some Porites, these deep-water
colonies are not particularly large; their growth
rates are much slower, which is probably due to
food limitation rather than temperature.
OCTOCORAL AGES
The octocoral groups are taxonomically as much
of a mess as are the scleractinians. In particular,
the leather corals have recently been found to
be essentially unidentifiable using current/traditional
methods. Fortunately for this article, the
ages of leather corals cannot effectively be determined—a
fact that, in this case, likely saves a lot
of authorial arm waving.
The sea pens form one good octocorallian
group whose taxonomy actually makes sense, being
supported by both genetic and anatomical
characteristics. Given the situation in the rest of
the corals, this fact deserves a GASP! of taxonomic
astonishment. Sea pens are mobile soft corals
LEFT: HURL WWW.SOEST.HAWAII.EDU/HURL/ RIGHT: BRIAN J. SKERRY/NATIONAL GEOGRAPHIC STOCK
80 CORAL