Barney Nietschmann Jr 
Exhausted and dying, a harpooned 
dugong is pulled to the boat, below. 
After a successful dugong hunt, 
carcasses are laid out on the beach, 
right. A dugong is butchered by the 
man who harpooned it, one of his 
mother’s brothers, and select 
members of the hunting crew. Adult 
females are the most prized dugongs 
because they are fattest. Males 
are hunted when there are no 
females in the vicinity. 
Bernard Nietschmann 
leeside reef zones. Daily grazing 
amounts are estimated to average 80 
to 100 pounds for an adult dugong 
and 10 to 15 pounds for a large green 
turtle. Except for Halophila , found 
in sheltered intertidal island flats, the 
commonly grazed sea grasses, such 
as Thalassia, Thallasodendron, and 
Cymodocea, do not occur in dense 
single-species stands. Instead they are 
found mixed and scattered over large 
areas depending on depth, type of bot- 
tom, and exposure. Any one particular 
sea-grass bed cannot support long- 
term grazing; therefore, sea-grass 
availability, density, and recover}- rate 
are the most important factors deter- 
mining the presence and movements 
of dugongs and green turtles. 
Seasonal and episodic fluxes in en- 
vironmental conditions also signifi- 
cantly affect herbivore presence and 
movements and, accordingly, the tim- 
ing and predictability of hunting. 
Tidal ranges and currents, water tur- 
bidity, and wind intensity and direc- 
tion all influence temporal and spatial 
distributions of dugongs and green tur- 
tles. Extremely strong tidal streams 
(frequently six to seven knots and even 
more in narrow- channels between reef 
sets), an eleven-foot tidal range, in- 
termittent days and weeks of turbid 
and clear water, and two main seasons 
dominate marine conditions and her- 
bivore habits. 
Dugongs are highly sensitive to tidal 
fluctuations and changes in water clar- 
ity. Moving from place to place, they 
often swim with the flood and ebb 
tides. Some sea-grass beds are so shal- 
low that they are dry at low tide; 
dugong feeding is thus limited to high- 
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