THE ANEMONEFISH SYMBIOSIS

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THE ANEMONEFISH SYMBIOSIS

• Daphne G. Fautin
• Department of Ecology Evolutionary Biology
• And
• Natural History Museum
• University of Kansas

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SOME TRUTHS ABOUT NEMO
OR
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THE STORY Mom and Dad had 100 babies . . .
After Mom and 99 babies are eaten by a
barracuda, Dad cares for Nemo
Nemo rebels against Dad, is caught and put in an
aquarium in a dentists office
Dad and his friends swim to Sydney to find and
rescue Nemo
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THE DRAMATIS PERSONAE
anemonefish (clownfish)

symbiosis (not necessarily a mutualism)
sea anemone
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WHAT IS A SEA ANEMONE??
Anatomically simple one body opening, no organs
BUT functionally complex
including sexual reproduction
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WHAT IS A SEA ANEMONE?? there are 1000 species
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WHAT IS A SEA ANEMONE??
Phylum Cnidaria
PHOTO BY ART REED
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WHAT IS A SEA ANEMONE??
All members of Phylum Cnidaria form nematocysts
-- the most complex structure secreted by an
animal
Used offensively (to capture prey) and
defensively (to protect themselves)
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WHAT IS A SEA ANEMONE??
All members of Phylum Cnidaria form nematocysts
-- the most complex structure secreted by an
animal
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BACK TO THE STORY
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THE SETTING
CORAL REEFS
AND SOFT BOTTOMS
SHALLOW WATER
ZOOXANTHELLAE
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Anemone data from Hexacoral website
hercules.kgs.ku.edu/hexacoral/anemone2/index.cfm
Fish data from FishBase www.fishbase.org
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DIVERSITY
10 (?) species of anemones
In three families that are only distantly related
to one another
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DIVERSITY
25 species of fishes
All family Pomacentridae (damselfishes) these
in genus Amphiprion
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fishDIVERSITYcontinued
Premnas spine-cheek common in home
aquaria
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FACTOID Not all possible combinations occur in
nature

• One species of fish lives naturally with all 10
  host species
• About a third live with only one host species

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many can live with unnatural hosts, including the
Caribbean Condylactis
Photo by George Miller
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THE STORY Mom and Dad had 100 babies . . .
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THE STORY Mom and Dad had 100 babies . . .
TRUTH 1a A pair of anemonefishes lives in a
single anemone in very rare instances they
belong to different species
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THE STORY Mom and Dad had 100 babies . . .
TRUTH 100 is low -- several hundred eggs is the
typical brood
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THE STORY After Mom and 99 babies are eaten by a
barracuda, Dad cares for Nemo
TRUTH 2 A barracuda? Perhaps.
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THE STORY After Mom and 99 babies are eaten by a
barracuda, Dad cares for Nemo
TRUTH 2a Although Dad is the primary caretaker
for the eggs, the eggs hatch at night, and the
larvae go into the plankton, where they mature
THEREFORE Mom and Dad never know their kids
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BUT If Mom and Dad do not live with and, in
fact, never know their kids ..
As they say, truth is stranger than fiction!!
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For such as system to work, since anemonefish
can live a decade or more
The anemones must live a century or more
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THE STORY Nemo rebels against Dad by swimming to
the edge of the reef, is caught and put in an
aquarium in a dentists office
TRUTH 3
By now, Dad would be Mom!
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THE STORY Nemo rebels against Dad by swimming to
the edge of the reef, is caught and put in an
aquarium in a dentists office
TRUTH 3a Anemonefish are easy to catch
Outside the anemone they have no defense
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HOW does an anemonefish tolerate life among the
tentacles?
It is NOT immune to being stung
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BECAUSE Outside their anemone they have no
defense
An anemonefish rarely ventures far from its
anemone for long
THE TRUTH IS 1) Nemo would not have gone to the
edge of the reef
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In short, IF
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THEN
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Anemonefish never occur without a host anemone in
nature (the relationship is obligate)
Anemones of MOST host species seldom occur
without fish symbionts but they can (the
relationship is facultative)
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Shortly after fish collectors left
THEREFORE anemonefish can be important
-- and may be essential --
for an anemones well being or life
a mutualism
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THE STORY Mom and Dad had 100 babies . . .
THE TRUTH believable
After Mom and 99 babies are eaten by a
barracuda,
possible
believable -- but only before hatching (and in
the presence of Mom)
Dad cares for Nemo
happens all the time (except for the rebellion
part)
impossible (of course!)
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FACTOID
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NOW, A QUESTION FOR YOU
The premise of the film was not just to FIND
Nemo, but to RELEASE him from his artificial
environment so he could go home
Why the dramatic rise in keeping anemonefishes??
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THE SEQUEL (part 1)
Aquarium fishes are being released
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THE SEQUEL (part 2)
Marine biogeography is poorly understood
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THE ULTIMATE MORAL OF THE REAL STORY
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ON THE OTHER HAND
Nemo was safe in the dentists aquarium
and since his anemone was left on the Great
Barrier Reef, it could be lived in by other
anemonefish
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WITH THANKS TO
An On-line Atlas of Marine Diversity www.iobis.org
National Science Foundation grants
Jerry Allen Adorian Ardelean Meg Daly Suman
Kansakar Jack Randall Amanda Schmidt other
photographers, buddies, etc.
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THE STORY Mom and Dad had 100 babies . . .
After Mom and 99 babies are eaten by a shark,
Dad cares for Nemo
Nemo rebels against Dad, is caught and put in an
aquarium in a dentists office
Dad and his friends swim to Sydney to find and
rescue Nemo