FISHERY BULLETIN: VOL. 72, NO. 3 



the source of a chronic pollution problem near that 

 spill. 



It is quite possible that normal functions of sed- 

 iments will be disrupted when contaminated by 

 oil. Changes in the sediments that are subtle and 

 difficult to detect, such as decreased nutrient re- 

 cycling and community metabolism, could result 

 in the loss of significant contributions to the pro- 

 ductivity and stability of an area. Although oil in 

 sediments has been monitored and measured after 

 several spills, other aspects of the oil-sediment 

 relation have yet to be studied. 



BIOLOGICAL EFFECTS OF 

 OIL POLLUTION 



Blumer (1970, see footnote 3) summarizes the 

 potential damage to organisms from pollution by 

 crude oil and oil fractions as follows: 



1. Direct kill of organisms through coating and 

 asphyxiation. 



2. Direct kill through contact poisoning of or- 

 ganisms. 



3. Direct kill through exposure to the water- 

 soluble toxic components of oil at some distance in 

 space and time from the accident. 



4. Destruction of the generally more sensitive 

 juvenile forms of organisms. 



5. Destruction of the food sources of higher 

 species. 



6. Incorporation of sublethal amounts of oil and 

 oil products into organisms (resulting in reduced 

 resistance to infection and other stresses — the 

 principal cause of death in birds surviving im- 

 mediate exposure to oil). 



7. Incorporation of carcinogenic and potentially 

 mutagenic chemicals into marine organisms. 



8. Low-level effects that may interrupt any of 

 numerous events (such as prey location, predator 

 avoidance, mate location or other sexual stimuli, 

 and homing behavior) necessary for the propaga- 

 tion of marine species and for the survival of those 

 species higher in the marine food web. 



Some of the potential effects described by 

 Blumer may be obvious, such as the direct deaths 

 from acute exposures. Less obvious indirect 

 deaths may occur from effects at either the indi- 

 vidual or population level. Individual organisms 

 subjected to sublethal exposures may undergo an 

 "ecological death" if they are less capable of ad- 

 justing to and responding to natural changes 

 (stresses) in their physical and biological envi- 

 ronments. For example, postmolt Tanner (snow) 



crab, Chionoecetes bairdi, lost legs during short 

 exposures to crude oil (Karinen and Rice, in 

 press). Even though the crabs lived through the 

 exposure, they probably could not have survived 

 in the natural environment because some of them 

 lost as many as seven legs, including both chelae. 

 Moreover, crabs or other adversely but suble- 

 thally affected organisms would be more likely 

 to be eliminated by natural selection. 



Effects from chronic exposure may be adverse to 

 a population over a period of time if exposed but 

 normal-appearing adults have their ability to re- 

 produce seriously impaired. This loss may be due 

 to physiological changes such as reduced fecun- 

 dity and delayed ovary development or to im- 

 paired behavioral mechanisms which could pre- 

 vent mate location and identification or homing 

 and timing of spawning. Although the effects at 

 this level might not result in death of the adult, 

 they could induce a trend of decreasing numbers 

 that might eventually eliminate the population or 

 race. 



Hydrocarbons in the Marine Food Web 



Blumer (1967, 1969) and Blumer, Guillard, and 

 Chase (1971) studied the fate of organic com- 

 pounds in the marine food web. They found that 

 certain hydrocarbons, even highly unsaturated 

 ones, are stable once they are incorporated into a 

 particular marine organism and that they may 

 pass through many members of the marine food 

 web without alteration and may actually be con- 

 centrated in tissue. Most hydrocarbons are lipid 

 soluble and thus may accumulate in food webs to 

 the point where toxic levels are reached. This 

 pathway is illustrated by the well-documented 

 chlorinated hydrocarbon group of pesticides. 



The entrance of oil-derived hydrocarbons into 

 marine food webs has been observed several times 

 at several trophic levels. Conover (1971) reported 

 that l(X7f of the bunker C oil in the water column 

 after the Chedabucto Bay spill was combined with 

 zooplankton and that their feces contained up to 

 1% oil. Mironov (1968) also noted the ability of 

 some zooplankters to accumulate hydrocarbons. 

 The incorporation of hydrocarbons into the food 

 web at these primary levels assures exposure at 

 all higher trophic levels. 



Blumer, Souza, and Sass (1970) and Ehrhardt 

 ( 1972 ) reported pollution-derived hydrocarbons in 

 shellfish. Uptake and retention of labeled hy- 

 drocarbons of several classes by a marine mussel, 



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