The impacts of coral and shell collecting - The Great Barrier Reef: An Environmental History - page 149

Damage to giant clams was also reported in 1937 at the reef on the south-
eastern side of Green Island, where visitors habitually took small clams away
with them. Clams were also killed in situ , as a National Parks Ranger stated: 'Fish
spears have on occasions been thrust into clams, killing them' . 41 One example
of that type of destruction was given by National Parks Ranger McKeown, who
stated that 'some time ago a large clam was brought in from one of the outer
reefs, and placed in shallow water for exhibition purposes; recently this clam
was speared, and killed'. Consequently, the National Parks Ranger argued, the
collection of those animals from Green Island reef should be prohibited.
Giant clams were removed from the reef - or were damaged in situ - for a
variety of reasons besides popular fear of the danger they presented to swimmers.
Barrett (1930, pp378, 380) acknowledged that the demand for unusual shell
species - particularly the giant clams - was considerable, and he stated that the
valves of Tridacna gigas were sought as garden ornaments and home aquaria. Ellis
(1936, pp83-4) described the use of giant clams for food, at Raine Island, but also
their exploitation as curios, stating that:
A feature which impressed us considerably at Raine Island was the enormous
number of giant clam-shells ( Tridacna gigas ) found in a shallow lagoon,
perhaps four feet deep at low tide. […] An average pair of these enormous
bivalves would weigh about three hundred-weight and measure about three
feet in length; some indeed were considerably larger. [...] The fish of these
Tridacna are enormous, but the only portion used by our Chinese labourers
for food was the muscle connecting the two sides. It will convey some idea
of the size of these gigantic mollusca if it is realized that this muscle usually
weighs about five pounds [...]. The giant clams with their inner surface of
pure white, like polished marble, are considerably sought after as curios.
An example of the ornamental use of giant clam shells, at Orpheus Island in
1967, is shown in Figure 9.8.
Extensive damage to giant clams in the Great Barrier Reef also occurred as a
result of the activities of poachers, particularly from Taiwan, China and Korea.
Domm (1970, p44) stated:
The clam fishery is exploited by Nationalist Chinese and Korean fishermen,
and the semi-dried clam meat produced commands an excellent price in the
Orient. The adductor muscle is cut from the clams and dried aboard the
fishing vessels. The operators generally work in knee-deep water at low tide
and, although they leave the clam shells where they are, they damage a large
amount of coral wading to them.
Although considerable poaching of Tridacna gigas took place after 1970, it is
clear that giant clam numbers had already declined since European settlement.
Moreover, due to the slow growth rates of those organisms, the overall increased