E. Half-time — 30.0 ml of crude oil added for the last half 

 of the incubation period (poured on top of the sand 

 after 28 days) 



F. Quarter-time — 30.0 ml of crude oil added for the last 

 quarter of the incubation period (poured on top of the 

 sand after 42 days) 



Groups receiving different dosages of oil did not differ 

 significantly in hatching success, embryonic survival or 

 incubation time. Hatchlings were significantly smaller in light 

 dosage subsamples than in other dosage groups. These results 

 suggest that if turtle eggs are deposited in sand after oil 

 contamination has occurred, significant mortality is not likely, 

 but hatchlings may be smaller than normal. 



Addition of 30 ml of oil to isubsamples during the last half 

 or last quarter of incubation resulted in significantly lower 

 hatching success than controls or subsamples exposed to oil at 

 the initiation of incubation. Significant mortality of embryos 

 in the half-time and quarter-time subsamples occurred shortly 

 after exposure to oil. No significant differences occurred in 

 incubation times between these groups. Hatchlings were smaller 

 in the half-time and quarter-time subsamples than in other 

 groups. Thus, sensitivity to oil appears to vary with the age of 

 the embryos. 



The results of this study indicate that if oil washes up on 

 a sea turtle nesting beach outside of the nesting season, even if 

 it is only a short time before the season begins, it will 

 probably be weathered to a nontoxic state (i.e., tar) by the time 

 nesting turtles arrive. However, if oil washes up on a nesting 

 beach while eggs are incubating in the sand, significant 

 mortality may occur if the oil washes up on the beach to the 

 level where the nests are buried. Apparently, the effects of a 

 one-time oil spill on hatching are relatively short-lived and 

 would threaten at worst a single year's reproductive effort. 



322 



