LONG-TERM IMPACT OF THE AMOCO CADIZ CRUDE OIL SPILL ON OYSTERS 

 Cvassostvea gigas AND PLAICE Pleuroneotes platessa FROM ABER BENOIT 

 AND ABER WRAC'H, BRITTANY, FRANCE 

 I. OYSTER HISTOPATHOLOGY 

 II. PETROLEUM CONTAMINATION AND BIOCHEMICAL INDICES 

 OF STRESS IN OYSTERS AND PLAICE 



by 



1 2 



Jerry M. Neff and William E. Haensly 



1) Battelle New England Marine Research Laboratory, Washington Street, 

 Duxbury, MA 02332, USA 



2) Texas A&M University, Department of Vetinary Anatomy, College Station, 

 TX 77843, USA 



INTRODUCTION 



On the evening of 16 March 1978, the. Liberian-registered super- 

 tanker Amoco Cadiz (233,680 tons deadweight) ran aground and subse- 

 quently broke up on Men Goulven rock, Roches de Portsall, approximately 

 2 km off Portsall on the Breton coast of France. Over a period of 

 several days the complete cargo of the supertanker, which consisted of 

 120,000 metric tons of light Iranian crude oil, 100,000 tons of light 

 Arabian crude oil and 4,000 tons of bunker fuel was spilled into the 

 coastal waters. By mid April the oil had spread to and contaminated in 

 varying degrees 375 km of the north and west coasts of Brittany (Hess, 

 1978; Spooner, 1978; Southward, 1978). At the time, it was the largest 

 oil spill in maritime history. There have been two larger spills since 

 then. Two estuaries in the heavily impacted area, l'Aber Benoit 6 km 

 east of the spill and l'Aber Wrac'h 9 km east of the spill, face west 

 and became heavily contaminated with spilled oil. 



Aber Benoit and Aber Wrac'h are biologically rich and before the 

 spill supported large oyster mariculture operations and other commercial 

 fisheries. It was therefore of considerable economic and hygenic impor- 

 tance to accurately assess the progress of the long-term recovery of the 

 estuarine biota from the impact of the oil spill. 



Several factors relating to this spill, including the large volume 

 of oil spilled, the prevailing winds and currents which drove much of 

 the oil ashore, adverse weather conditions and large tidal prisms which 

 resulted in the incorporation of large amounts of oil into bottom sedi- 

 ments, and the extreme biological richness of the impacted area, all 



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