11 



Table I. Mean PCB and DDE residues (pprn lipid weight) in cormorants 

 (Phalacrocorax spp. ) 



are frequently small, a general picture of 

 global marine contamination by DDT and 

 PCB compounds can be presented. Some of 

 the available data on cormorants have been 

 summarized (Table 1). With the exception of 

 the residue values reported for the double- 

 crested cormorant (Phalacrocorax auritus) in 

 southern California, where the birds were ex- 

 posed to industrial contamination from the 

 Los Angeles area (Gress et al. 1973), the 

 samples were obtained from areas reasonably 

 remote from point sources of contamination. 

 The DDE residues in the Auckland Island 

 shags (Phalacrocorax carunculatus) were 

 somewhat lower than in cormorants from 

 Amchitka and Agattu at the equivalent lati- 

 tude in the northern hemisphere. However, 

 PCB values in the southern hemisphere birds 

 were lower by 1-2 orders of magnitude. 



Other data from biocenotic equivalents in 

 the two areas support the conclusion that 

 DDE levels are slightly lower in the southern 

 than in the northern hemisphere but that PCB 

 values are lower by 1-2 orders of magnitude 



(Bennington et al. 1975; White and Rise- 

 brough 1977). The DDE levels in an egg of a 

 New Zealand falcon (Falco novaeseelandiae) 

 were equivalent to those in eggs of peregrines 

 from Amchitka, but PCB levels were an order 

 of magnitude lower. Comparable differences 

 were found between auklets (Aethia pusilla 

 and Cyclorrhynchus psittacula) and the tufted 

 puffin (Lunda cirrhata) of the Aleutians and 

 the diving petrel (Pelecanoides urinatrix) from 

 the Snares Islands of southern New Zealand. 



The DDE levels in eggs of the guanay were 

 somewhat higher than those from New Zea- 

 land or the Aleutians, suggesting local 

 sources of DDT contamination in Peru (R. W. 

 Risebrough et al., unpublished manuscript). 



A comparison of the cormorant samples 

 from the Aleutians and the eggs of two cor- 

 morants (Phalacrocorax carbo and P: aris- 

 totelis) breeding in Iceland suggests that 

 levels of DDE and PCB contamination in the 

 two oceanic areas are similar. In five species 

 of fish obtained from Amchitka in 1974, DDE 

 residues ranged from 1 to 5 ppb; PCB resi- 



