Second Home of Fish From Dinosaur Age Is Found
By MALCOLM W. BROWNE
The coelacanth, a very rare fish with a pedigree older
than the dinosaurs, has delighted biologists by turning up in Indonesia.
Two of these ugly but fascinating fish have been discovered nearly 6,000
miles from the coast of southern Africa, the only place in the world where
coelacanths had hitherto been found.
The discovery, reported in Thursday's issue of the journal Nature,
kindled hopes that the species might not be quite as geographically
isolated and endangered as was believed.
Until 60 years ago the coelacanth (pronounced SEE-la-kanth) and all its
crossopterygian cousins were believed to have become extinct some 25 million
years before the demise of the dinosaurs, and these fish were known only
from their fossils.
But on Dec. 22, 1938, a fisherman on the Chalumna Bank in the Indian Ocean
off the African coast landed a steel-blue fish about five feet long, with a
paddlelike tail and peculiar ventral fins. Recognizing his catch as something
unknown, the fisherman took it to a local scientist, and the creature was
soon identified as a coelacanth typical of the early Mesozoic era.
Scientists named it Latimeria chalumnae, and the fish was hailed in
headlines around the world as a living fossil; the discovery of a living
dinosaur could hardly have been more astonishing.
One reason for the widespread interest in the coelacanth was the belief by
scientists that crossopterygian fish related to the coelacanth were the
ancestors of amphibians, and hence, of all tetrapods -- four-limbed
creatures -- including human beings. In recent years, however,
comparisons of the DNA of coelacanths with other
animals have convinced most scientists that air-breathing lung fish rather
than the crossopterygians were ancestral to tetrapods.
Since 1938 several hundred coelacanths have been caught, all
in African waters and most of them near the Comoros Islands. Recent
treaties have banned the intentional hunting of coelacanths, but they are
still occasionally brought to the surface by accident. No coelacanth has
ever survived more than a few hours in captivity.
Scientists assumed that some fluke had saved the Comoros
Island coelacanths from the general extinction of crossopterygians 90
million years ago, and that it was unlikely that coelacanths would be found
at any great distance from southern Africa. But on July 30 of this year an
Indonesian fisherman named Om Lameh Sonathon and
his crew landed a 64-pound fish some four feet long using a shark net off
the island of Sulawesi.
The fishermen knew what they had, because they were briefed
by a American scientist a year ago. The scientist was Dr. Mark V. Erdmann,
a ostdoctoral researcher in biology from the University of California at
Berkeley, who happened to be on his honeymoon in Indonesia in September
1997. His wife, Arnaz Mehta Erdmann, a
naturalist, was walking through a fish market in Manado when she spotted a
large fish being wheeled along on a hand cart. She recognized it instantly
as a coelacanth.
Dr. Roy L. Caldwell, Erdmann's department head at Berkeley,
said in an interview that the Erdmanns were unable to do anything about
their find other than photograph it, because they were scheduled to return
to California on the next day. "What can you do with a smelly, 80-pound
fish when you have to make a flight?"
Caldwell asked.
But the photographs convinced the National Science
Foundation, the Indonesian Institute of Sciences and the National
Geographic Society to finance further investigation by Erdmann, who
returned to Sulawesi and undertook interviews with fishermen near Manado.
Two months ago the search was rewarded when fishermen
brought up a coelacanth. The fish are not good to eat, Caldwell said,
because their oily flesh is strongly impregnated with urea. The fishermen
and Erdmann towed the fish to shore and kept it alive and swimming for
about three hours. When the fish died, it was frozen for further examination.
"Judging from the fish's external appearance," Caldwell said,
"we think it's the same species as the coelacanths caught in the Comoros,
but we can't be sure until we've compared their DNA."
But all the Comoros coelacanths reportedly were "steel blue,"
according to their finders, while the Indonesian specimens were brown, he
said.
Several commercial organizations and aquariums have tried
over the years to catch coelacanths alive and keep them in tanks. But the
fish are usually injured by hooks, and they appear unable to stand the
changes in temperature and pressure when brought to the surface.
Among the scientists who strongly oppose the intentional
hunting for coelacanths even by scientists is Dr. Hans Fricke of the Max
Planck Institute for Behavioral Psychology in Seewiesen, Germany. Fricke
and his colleagues have made several expeditions in a small submarine to
the coelacanths' habitat off the Comoros and
have made movies recording the peculiar nighttime browsing behavior of the
fish as they search for prey on the ocean bottom.
Dr. Sante Paabo, a molecular biologist at the University of
Munich who has investigated coelacanth DNA, called the discovery in
Indonesia exciting.
"Indonesia is so far from the Comoros that this must really
be another population of the animals," Paabo said. "That may mean that
coelacanths are not quite as endangered as we feared."
But Caldwell warned that "there are probably only a few of
these fish in Indonesia, and the species is certainly still endangered."
"One bad thing about this discovery," he added, "is that
people may get the idea that coelacanths are plentiful and conservation
efforts will weaken. That must not be."
Copyright 1998 The New York Times Company