Charonia Research Digital Collection New
Miyake-Jima
1957
It's 1957 and Japanese scientists
travel to the island of Miyake-Jima to study a strange disease affecting a
coral reef. The island’s people have noticed a strange increase in the number
of the large, venomous crown-of-thorns starfish. Over the following years they
kill large numbers of the starfish attempting to protect the living coral upon
which the starfish is feeding. The Japanese scientists noted that they had
observed giant triton shells feeding on the crown-of-thorns starfish, in
research published only in Japanese.
5 years later
This same species of starfish is
noticed in increasing numbers at Green Island, off Cairns here in Australia.
Over the next five years, the starfish outbreak will consume much of the living
coral at Green Island and other reefs in the vicinity.
The giant triton is again observed
feeding on crown-of-thorns starfish and research in Queensland is commenced on
the feeding rate and prey preference of the giant triton. Tests are done with
three species of starfish; multiple specimens of each species are placed in
cages with giant tritons.
The results showed that while each
giant triton ate one crown-of-thorns starfish per week on average, it ate less
crown-of-thorns starfish than another relatively common species of starfish.
The research concluded that the crown-of-thorns starfish was not the preferred
prey of the giant triton.
This conclusion was further supported
by similar research done overseas, despite the observation that giant tritons
were often located on the Great Barrier Reef, and elsewhere, were eating
crown-of-thorns starfish.
30 years later
It becomes apparent that such a conclusion about prey preference of the giant triton is simply not justified, given the crown-of-thorns starfish often escapes complete predation because of its relatively high mobility. It is apparent that there is much confusion between prey capture and prey preference of the giant triton. It is suggested this distinction is relevant to control of prey.
40 years later
Australia is unsuccessful in its
attempt to list the giant triton in Appendix 2 of the Convention in Trade in
Endangered Species (CITES) because Japan objects on the grounds of ‘no
evidence’ for the alleged endangered status of giant triton.
50 years later
The Great Barrier Reef Marine Park
Authority reports that outbreaks of crown-of-thorns starfish are a threat to
the Great Barrier Reef and controls are needed.
60 years later
While the giant triton may be
protected on the Great Barrier Reef and elsewhere in Queensland, there is still
no evidence this protection has resulted in restored populations of the giant
triton. However, there is evidence of continuing illegal collection and trade
in Indonesia where it is also legally protected.
It is now worth reconsidering whether
the existing local protection is sufficient or whether further international
protection is required by listing the Giant Triton in
Appendix 2 of the Convention on International Trade in Endangered Species
(CITES).
The giant
triton (Charonia tritonis) is a
beautiful shell and a well-known predator of the crown-of-thorns starfish (Acanthaster
planci). In many parts of the third world, it is still being collected in
large numbers and sold to tourists as ornaments. As you admire the beautiful
shell, spare a thought for the hungry mollusc that died. And don’t forget, they
live on starfish. Many species of starfish are known to outbreak in different
parts of the world. Prior to human collection, the giant triton might have
controlled starfish numbers not by eating the many, but by preventing the
aggregation that precedes the outbreak. At present, little is known of any
aspect of the triton’s ecology despite its obvious importance in controlling
starfish numbers.
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