Larval Survival and Growth 
Survival of larvae exposed to No. 2 fuel oil (WAF) was assessed primarily 
under static conditions. Glass scintillation vials were completely filled with 
water siphoned from the flow-through dosing tanks. 15 to 20 two to three day 
old N. obsoletus or C. fornicata larvae were pipetted into each vial, and 
Isochrysis galbana was provided as food at an initial density of about 1x10 
cells/ml. Vials were then tightly capped to minimize volatilization of 
hydrocarbons. Each experiment was conducted in triplicate. Larvae were 
counted daily and survivors were transferred to fresh medium. The experiments 
were conducted at room temperature (21-23°C), well within the range for 
good larval growth (10, 31). 
One preliminary flow-through experiment was conducted with about 100 
two-day old C. fornicata larvae (approximately 420 Aim in shell length), using a 
system similar to that described by Calabrese and Rhodes (10). Water from the 
oil-dosing tanks was siphoned at approximately 50 ml/minute into 
flow-through chambers containing larvae, and 200 ml /. galbana suspension 
added at the beginning and end of each day as a feeding supplement. 
Completely filled, capped quart glass jars were used to determine the effects 
of the oil on growth and survival of larval C. irroratus. 75 Stage I zoea were 
added to each jar. Larvae were fed Artemia salina nauplii provided in excess 
numbers. Larval mortality was determined daily, and survivors were transferred 
to fresh medium. These experiments were conducted at 15°C, the optimal 
temperature for development of C. irroratus (28), and under a 12L:12D 
photoperiod. In a separate series of experiments, at least five individuals of 
each larval stage were harvested from control and “0.1” ppm levels to monitor 
growth. Larval carapace lengths were measured using an ocular micrometer. 
Dry weights were then determined using a Perkin-Elmer Electrobalance after 
the larvae were rinsed with distilled water, and dried at 80°C for 24 hours in 
pre-weighed foil pans. 
RESULTS 
Adult and Larval Survival 
Exposure to a nominal concentration of 1.0 ppm was found to be lethal for 
all adults and larvae tested. Concentrations of “0.1” ppm and “0.01” ppm 
were sublethal to all test organisms for the particular exposure periods of our 
experiments. 
Mortality of N. obsoletus adults did not exceed five percent in any 
experiment at control, “0.01” ppm or “0.1” ppm exposure levels. Substantial 
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