The benthic zone in general, from the standpoint of damage and 

 recovery, seems to merit much greater attention in future oil spill 

 studies than it has characteristically received in the past. 



4. The fish fauna : The seasonal influence on the migratory be- 

 havior of the fish makes the effects of an oil spill dependent on the 

 season of the year. Adult fish can possibly avoid high concentrations 

 of oil; therefore, the greatest effects are to be expected largely in 

 those earliest life stages that are subjected to prolonged oil exposure. 



Most fish species of economic importance along the Baltic coast 

 spawn in the spring and early summer. An oil spill just before or 

 during this period will have a maximal effect on reproduction. Investi- 

 gations during this period should be concentrated on spring-spawning 

 herring, where differences in hatching success are relatively easy to 

 investigate. During other seasons, effects should be sought primarily 

 in species with slow roe development and/or spawning on deeper soft 

 bottoms, where oil effects probably persist for a longer period of time. 

 Also, the accumulation of oil in food animals, especially on deep soft 

 bottoms, may result in bioaccumulation in fish feeding on those food 

 items. This should be studied in connection with future spills. 



No acute fish mortality was observed following the spill. A large 

 mortality of small fish (probably gobies) in the littoral was, however, 

 observed about a month after the spill by local residents. This implies 

 that observations of fish should cover a longer period than the acute 

 phase of the spill. 



5. Integration of disciplines and studies : It is absolutely 

 necessary to have high caliber analytical chemistry available on an 

 interactive basis with the biological studies. Samples in the Tsesis 

 investigation were collected and preserved from the beginning, with 

 attention to minimizing extraneous contamination or introduction of 

 other ambiguities, to preserve the integrity of the samples for later 

 analysis. The storage of samples in anticipation of the funding for 

 their analysis proved to be an excellent investment. The chemistry 

 eventually showed the nature of the insult, which was necessary to 

 properly interpret biological effects. 



54 



