Table 5. Geometric mean DDE and PCB residue concen- 
trations (ppm, wet weight) in eggs of Alaskan seabirds, 
1973-76, ranked by region within species. Species are 
included only if eggs were collected in more than one 
region.® 


Species and region DDE PCB's 
Northern fulmar 
Gulf of Alaska 0.484 A 0.484 A 
Pribilof Islands 0.307 A 0.387 A 
Glaucous-winged gull 
Aleutian Islands 3.29 A 3.41 A 
Gulf of Alaska 0.324 B 0.548 B 
Black-legged kittiwake 
Gulf of Alaska 0.065 A 0.480 A 
Pribilof Islands 0.033 A 0.472 A 
Seward Peninsula 0.033 A 0.365 AB 
Bristol Bay 0.021 A 0.204 B 
Common murre 
Gulf of Alaska 0.448 A 0.625 A 
Pribilof Islands 0.205 B 0.239 B 
Seward Peninsula 0.141 B 0.182 B 
Bristol Bay 0.134 B 0.149 B 
Aleutian Islands 0.132 B 0.136 B 
Thick-billed murre 
Seward Peninsula 0.166 A 0.307 A 
Gulf of Alaska 0.147 A 0.259 A 
Aleutian Islands 0.145 A 0.090 B 
Tufted puffin 
Gulf of Alaska 0.278 A 0.518 A 
Bristol Bay 0.266 A 0.423 A 

4For each species, regional means that do not share the same 
letter are significantly different (P<0.05) from each other (DDE 
and PCB’s considered separately). 
kittiwake there were conspicuous differences among PCB 
levels; higher concentrations were found at Kodiak, 
Middleton, and St. Paul islands and lower ones at Round 
and Hinchinbrook islands and the Bluff Seabird Cliffs. In 
common murres, both DDE and PCB’s were higher at 
Middleton Island than at other sites. In tufted Puffins, the 
higher concentrations of both DDE and PCB’s were in 
eggs from Hinchinbrook Island, and the lower ones in eggs 
from the Semidi Islands. 
Among collection sites, there was no clear pattern in 
PCB/DDE ratios (Appendix III). They tended to be higher 
than average in one or more species at St. Paul, Ugaiu- 
shak, Middleton, and Buldir islands than at other sites, but 
there were often other species with low ratios at these sites. 
For other chemicals, there often were also significant 
differences in mean concentrations among the various col- 
lection sites (Table 6). Detailed information (i.e., sample 
size, number with residues, geometric mean, 95% confi- 
dence interval, and range) is presented in Appendix III for 
9 
each species. We were able to collect at least five eggs per 
site at two or more sites for six species, and comparisons 
can be made within species to reflect differences among 
the sites where they were collected (Table 6). 
Northern fulmar.—Concentrations of DDT were higher 
at the Semidi Islands than at St. George Island; for all 
other chemicals in which there were significant differ- 
ences, concentrations were higher in the samples from St. 
George Island. 
Glaucous-winged gull.—Concentrations of several 
chemicals were higher in eggs from the Semidi Islands or 
Shumagin Islands, or both, than in those from other sites. 
However, concentrations of other chemicals tended to be 
relatively low at those two sites. In general, concentra- 
tions of most chemicals were among the lowest in eggs 
from the Copper River Delta and Amalik Bay. 
Black-legged kittiwake.—Concentrations of several 
chemicals in eggs from Kodiak Island, and of dieldrin and 
mirex in eggs from Round Island, were higher than those 
in samples from other sites. However, the Round Island 
samples had among the lowest concentrations for other 
chemicals. Although also reflected somewhat in the other 
species, kittiwake eggs showed clearly the trend toward 
higher concentrations of HCB in the samples collected at 
the westernmost nesting colonies. 
Common murre.—Concentrations of DDD and DDT 
were highest at St. George and Middleton islands and 
lowest at Bogoslof, St. Paul, and Shaiak islands. The sig- 
nificant difference between St. George and St. Paul, 
which are near each other, was notable. 
Thick-billed murre. — Except for PCB’s, there were sig- 
nificant geographic differences in only two chemicals 
(DDD and oxychlordane) in this species. Concentrations 
of each were highest at King Island and lowest at Buldir 
Island. 
Tufted puffin.—Concentrations of several chemicals 
were higher in eggs collected at Hinchinbrook Island and 
the Barren Islands than in those from other sites. Concen- 
trations of most chemicals tended to be lowest in samples 
from Ugaiushak, Kodiak, and Shaiak islands. 
Species Differences 
Among eggs of species collected in two or more regions, 
the frequency of residue occurrence (Table 4) was highest 
in those of fork-tailed storm-petrel (frequency index 0.769), 
tufted puffin (0.677), horned puffin (0.662), pelagic cor- 
morant (0.645), and northern fulmar (0.559), and lowest 
in those of common murre (0.501), black-legged kittiwake 
(0.442), double-crested cormorant (0.396), and_thick- 
billed murre (0.385). These patterns were also reflected at 
certain sites where at least two of these species were col- 
lected (Table 3). In some species, the frequency of occur- 
rence was higher than for most other species in certain 
regions, but not overall. For example, frequencies of resi- 
dues were high in eggs of glaucous-winged gulls in the 
Aleutian Islands (0.593) and Bristol Bay (0.667), black- 
tO 
