The low number of individuals at station B could be a result of the 

 oil spill but it is more likely a result of the ground being turned over 

 during the clean-up procedure, a measure which destroyed the wrack more 

 or less completely. Since there were no storms during this period, when 

 Fucus might have blown ashore, the remaining wrack bed became rather 

 diminished, and this in turn influenced the animal life. 



8.2.6 Conclusions 



Unfortunately no similar investigation had been made in this area 

 either before or directly after the accident, which makes it difficult 

 to draw firm conclusions. The present investigation indicates, however, 

 that the oil spill from Tsesis has not had any great and long lasting 

 negative effects on the fauna of the wrack belts of the shore. It 

 seemed to recover rather quickly, due both to the short generation time 

 and the vagility of the animals. Another important factor was the time 

 of the accident . It took place in the late autumn when many animals had 

 already left the upper, most affected part of the ground in preparation 

 for hibernation. Had it happened in the early spring it is possible 

 that the results would have been different and shown longer lasting 

 effect . 



8.2.7 Acknowledgements 



The following persons deserve thanks for great help with exam- 

 ination of the animals: Dr. Carl-Cedric Coulianos (Brachycera and 

 Coleoptera), Dr. Torbjorn Kronestedt (Araneae), Dr. Lennart Cederholm 

 (Hymenoptera) and Dr. Hugo Andersson (Brachycera). 



8.2.8 References 



Backlund, H.O. 1945. Wrack fauna of Sweden and Finland, Ecology and 



Chorology, Lund. Acad, diss., Opuscula entomologica Suppl. 5: 1-236. 



Chinery, M. 1976. Nordeuropas lnsekter, En Bestamningsbok. Handledning 

 for bestamning av samtliga insektfamiljer i nordeuropa. Albert 

 Bonniers fb'rlag AB , Stockholm. 1-371. (In Swedish). 



188 



