13% died by 30 March, 25% by 31 July, 55% by August, 1972, and 86% by August, 

 1974 (Dow and Hurst 1975). Additionally, surviving clams showed a high 

 incidence of gonadal tumors (malignant neoplasms; Barry and Yevich 1975). Up 

 to 26.6% of the individuals in some samples were afflicted. No tumors were 

 found in clams from control areas. Highest incidences correlated with areas 

 receiving the highest amounts of oil. Subsequent histopathological 

 examinations of clams from other parts of the State, including the chronically 

 polluted inner Portland Harbor, have revealed that tumors in clams are rare, 

 which may suggest that the jet fuel or some component of it is the causal 

 agent (personal communication from J. Hurst, Maine Department of Marine 

 Resources, West Boothbay Harbor, ME; January, 1980). 



Further studies of Long Cove have confirmed and expanded the above results. 

 Gilfillan and coworkers (1977) concluded that 5 years after the spill "major 

 biological effects were still readily apparent" in the clam population. These 

 effects include absence of recruitment, continuing incidence of gonadal 

 tumors, and a significantly reduced growth rate. Growth rate reduction could 

 be related to the concentration of aromatic hydrocarbons in tissues. Sediment 

 analyses conducted in the summer of 1976 showed that many stations within the 

 cove still contained over 125 ppm weathered hydrocarbon material that was 

 similar to the spilled petroleum. These authors also report that for some 

 time after the spill marine bait worms (e.g., bloodworms) from the area showed 

 high mortality during shipping, and dealers ceased buying them. 



It has been reported recently (Dow 1978) that clams have successfully 

 established themselves in Long Cove, in fairly clean sediments that have been 

 redistributed over areas of oiled sediments by winter storms. These clams 

 continue to survive and grow until they reach the size at which their burrow 

 intersects the oiled sediment horizon, at which time they die. 



The impact of the 1973 Tamano spill on several components of the marine system 

 was investigated in July, September, and November of 1972 and again in August, 

 1973 (The Research Corporation of New England 1975). All groups of biota were 

 affected adversely; amphipods were completely absent from severely oiled 

 sites. The intertidal mudflats were most severely affected, followed by 

 intertidal rocky shores and subtidal benthic communities. Density and 

 diversity declined, and accumulations of petroleum hydrocarbons were found in 

 tissues. Waterbirds experienced high mortalities. By November and to a 

 greater extent by the next August, some recovery among waterbirds was noted. 

 However, severely oiled rocky areas were still void of biota in 1973, and 

 recruitment of shellfish to the oiled flats has not been observed. 



The most important factor controlling the extent of damage to an intertidal 

 area from spilled oil is its exposure to wave-action (Owens 1978). On shores 

 of high-wave energy, the oil is dispersed quickly by the violent action of the 

 waves, whereas on shores of low-wave energy the oil may persist for years 

 (Keizer et al. 1978). The removal of most of the oil by natural agents after 

 a moderate oiling of an exposed rocky shore may take only 3 to 4 months (Smith 

 1968). 



Approximately 1 year after the Nova Scotia coast was oiled severely, only 

 small amounts of oil remained on the rocky shores (Thomas 1973). Since much 

 of this oil was deposited in upper intertidal areas, where the least amount of 

 wave action is present, oil remained there for longer periods and delayed 



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