i 



100 I- 



CONTROL O 

 OILED • 



60 90 120 



TIME (minutes) 



ISO 



180 



Figure 9-6. Oil Spill: Comparison of Filtering Activity 

 of Mytilus edulis Collected From a Clean Area and from an 

 Area Impacted by an Accidental Spill of No. 6 Fuel Oil. 



week after the spill, another collection was made. Test results indicated that 

 feeding activity of the oiled mussels had improved to the point that no 

 differences could be found between control and oiled groups. 



In conclusion, the investigation demonstrates that (1) under laboratory 

 conditions an adverse reduction in filtration rate occurs in Mytilus edulis at 

 very low levels of continuous oil exposure; (2) the effect is reversible, since 

 recovery will gradually occur if the stressed animals are returned to unpolluted 

 conditions; and (3) a similar effect occurs in response to spilled oil in the 

 natural environment. 



ACKNOWLEDGEMENTS 



Grateful appreciation is extended to Ms. Terry Richie and Dr. James Heltshe 

 for their assistance v^th the statistical analyses. 



REFERENCES 



I.Abel, P.D. 1976. Effects of Some Pollutants on the Filtration Rate of 

 Mytilus. Mar. Pollut. BuU. 7(12): 228-231. 



120 



