Larval Survival and Growth 



Survival of larvae exposed to No. 2 fuel oil (WAF) was assessed primarily 

 under static coriditions. Glass scintillation vials were completely filled with 

 water siphoned from the flow-through dosing tanks. Fifteen to 20 two to three day 

 old N. obsoletus or C fornicata larvae were pipetted into each vial, and 

 hochrysis 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 tripHcate. 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 giuwth (10, 31). 



One preUminary flow-through experiment was conducted with about 100 

 two-day old C. fornicata larvae (approximately 420 ixva 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. Seventy-five Stage I zoea 

 were added to each jar. Larvae were fed Anemia 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 vAth distilled water and dried at SO'-^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 A^. 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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