Increased mortality was evident for both 3 d.o. and11
d.o. Acropora tenuis larvae in the Oil WAF treatment
compared to seawater controls, although this result was
not statistically significant due to high variability in both
treatment and control results. After 96 hours, mean
mortality for A. tenuis 3 d.o. larvae was 80% at 6.8 ppm
compared to 36% in seawater controls, and for A. tenuis
11 d.o. larvae was 76% at 3.7 ppm compared to 50% in
seawater controls. The toxicity of the Oil WAF increased
slightly with time of exposure. Hydrocarbon LC50 values
for 3 d.o. A. tenuis larvae ranged from 6.1 ppm at 48
hours down to 5.9 ppm at 96 hours (Fig. 1). The LC50 for
11 d.o. A tenuis larvae was 3.8 ppm after 96 hours, with
mortality rates prior to this time being too low for LC50
values to be calculated.