86 



which includes the environment and all animals in it. This is far more 

 complicated than the second step because it requires still more sophisti- 

 cated techniques and lars^e-scale experimentation in tlie field where 

 conditions cannot be controlled as they are in the laboratory. Such 

 studies are beginning in many parts of the country, but progress to 

 date has been limited. 



The Fisheries Service is undertaking studies such as the move- 

 ment of manganese, iron, and zinc in an estuarine ecosystem and energy- 

 relations in estuarine ocosystems. These studies are especially im- 

 portant because every pollutant is certain to have some effect, either 

 adverse or beneficial, on an ecosystem. Most effects are trivial but 

 some are not, and being certain is most difficult. 



Let me cite oil as an example of the state of our knowledge. The 

 effects of oil pollution on the animals in the water have received a great 

 deal of attention in recent years. Research is being done in many insti- 

 tutions in many countries. 



The study is complicated first "by the multiplicity of compounds of 

 which oil is composed and second by the differing degradability or 

 volatility of these compounds. Oil exposed on the surface of the water 

 partly goes in solution, partly evaporates, and partly degrades because 

 of the effects of the sun so that oil spilled 1 day is of a different 

 composition the next day. 



The tolerances of various aquatic animals to concentrations of cer- 

 tain components of the oil have been determined, we know that some 

 of the volatile fractions which are moderately soluble in water can be 

 toxic and that other less volatile fractions can be innocuous. This has 

 shown up in both laboratory and field observations. 



The thick crude oils are innocuous to most marine organisms. Many 

 animals have been found Avith crude oil in their guts without apparent 

 ill effects. Oysters can live for weeks in an aquarium under a layer of 

 crude oil, if oxygen is added to the water. 



The crude oil spills by the Torrey Canyon and from the wells in the 

 Santa Barbara channel caused virtually no identifiable change in the 

 ubsurface marine organisms. 



On the other hand, some of the refined oils such as diesel oil and 

 gasoline kill animals immediately and certain fractions may be re- 

 tained for long periods of time in the tissues of those that .survive 

 exposure. 



I-on.qr ten^T studies of tlie effects of the various oil fractions on ani- 

 mals are also underway in many places, but the picture is much less 

 clear. There has been great difficulty in separating the fractions of the 

 polluting oils from similar compounds in the fatty tissues of the ani- 

 mals and great difficulty in controlling experiments because of the un- 

 stable characteristics of the various oil fractions. 



An interesting example of such effects is the recent discovery bv one 

 of the Fisheries Service laboratories — this is the Auke Bay Labora- 

 tory, that one species of crab, and tliis is the snow cral:) — tended to '=hed 

 their le<rs in the presence of oil and survived for a time witliout legs. 

 Other species of crabs are not so affected at the same concentrations. 



As for tlie long term effects of oil on tlie entire ecosystem, we know 



very little. We know that we must expect changes but we do not know 



the conditions under which tliose changes will be trivial or significant. 



Perhaps I might add a brief comment relative to monitoring, such 



