274 



F. SALOMONSEN 



Table 4. Species composition of 8,304 birds killed by oil and examined in connection with five 

 pollution disasters in the Cattegat, 1969-71. (After Joensen 1972:12.) 



Oil incident no. 



a Somateria mollissima. Melanitta nigra, and M. fusca. 



takes place, the destruction of seabirds will be 

 enormous and immeasurable. 



As a result of five of the major oil pollution 

 incidents in the Cattegat from 1969-71, a total 

 of 43,500 birds were killed, of which 8,304 

 were examined and enumerated (Table 4). Al- 

 together, 21 or 22 species were involved, but 

 95% of all birds examined were diving ducks: 

 common eider and black and velvet scoters. 

 At present, it has not been possible to identify 

 any decrease in the number of these ducks in 

 Danish waters due to oil pollution. However, 

 if these disasters continue, it can be expected 

 that duck populations of northern Europe and 

 the Baltic area will be severely reduced, and 

 that an overall decline will take place from 

 which the birds may not be able to recover. 



A particularly disastrous year was 1972, 

 when large numbers of ducks were killed as a 

 result of rather small oil spills. A tanker disas- 



ter in March 1972 off the eastern coast of Jut- 

 land, in the northern Cattegat, and another in 

 December 1972 in the Danish Waddensea, 

 both took place in areas critical to major con- 

 centrations of sea ducks. A total of more than 

 60,000 birds were killed, of which about 95% 

 consisted of the same three species of diving 

 ducks mentioned above. These tragic events 

 represent a further increase in the annual mor- 

 tality of birds caused by oil, and there is rea- 

 son to believe that a critical upper limit is 

 rapidly being approached. 



It appears, however, that the measures 

 taken by pollution control and naval authori- 

 ties have greatly improved in recent years. In 

 January 1973, when a Polish merchant vessel 

 collided with a Swedish tanker in the Sound, 

 about 300 tons of heavy fuel oil were released 

 into the sea. Several Danish and Swedish 

 ships working in cooperation succeeded in dis- 



