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Biology and embryology of the
chambered nautilus (Nautilus belauensis)
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The Waikiki Aquarium collaborated with Dr. John Arnold, formerly from the University
of Hawaii, Dr. Bruce Saunders of Bryn Mawr College, Dr. Peter Ward of the
University of Washington, Dr. Neil Landman of the American Museum of
Natural History, and others, to unlock the secrets of this "living fossil".
In 1984, we used sonic transmitters to track living Nautilus belauensis in Palau,
Micronesia, in order to learn more about its daily movements. We discovered that Nautilus
moves as deep as 467 meters (1541 ft.) during the day, and at dusk ascends to depths as
shallow as 85 meters (280 ft.). Temperatures at these depths ranged from 8º C to 24º C (46º to 75º F).
Using the results from our field research, we constructed aquariums that allowed
temperatures to vary from 14º C to 22º C (57º to 72º F). The aquariums were not pressurized.
Adult nautilus in these aquariums laid eggs continuously over several years. The
eggs were maintained in separate incubator tanks at a constant temperature of
22º C (72º F), corresponding to the water temperature in the shallower depths visited by the
adult nautilus at night. This "guess" at the correct incubator temperature resulted
in the discovery of the first nautilus embryos known to science in 1985. A preliminary
description of the nautilus embryo was published in Science in 1986. We
predicted that the embryo would take up to a year to hatch -- a prediction that
was confirmed in December 1988, when our colleagues in Japan hatched the first
nautilus. On October 27, 1990, we hatched our first Nautilus belauensis. Of the
ten hatchlings produced at the Waikiki Aquarium, two survived to over one year
of age, providing the first growth data on young nautilus.
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