station 



Depth 

 (m) 



Fig. 6. Vertical cross-section profiles ol density (in a, units) along five west 

 to east transect lines along the southern Chukchi Sea Continental 

 Shelf. Panels are arranged from north (topi to south (bottom) 

 (cf. Frontispiece). Isopycnals are illustrated m ().!i units of o,. 



Glaucous Gull (Lams hyperhoreiis) . This gull was about 

 equally abundant in SCW and BSAW as recorded by lO-min 

 transects (Table 2). Based on 15-niin station counts (Table 3), 

 it was most abundant in SCW and approximately equally 

 common in BSAW and ACW. The more homogeneous 

 distribution of this species across the three water mass types 

 compared to the herring gull may be due to colony distribution 

 and adjacency. Glaucous gulls nest in small colonies 

 (<100 individuals) from Kolyuchin Bay eastward to capes 

 Serdtse Kamen and Dezhnev on the northern coast of the 

 Chukchi Peninsula, and on the coast of western Alaska from 

 Cape Lisburne south to Kotzebue Sound (NO A A, 1988). 

 Larger colonies (> 1 00 individuals) exist near Cape Thompson 

 and at the Diomede Islands (Sowlsf'/fl/.. 1978: NOAA, 1988). 



Black-legged Kittiwake jRissa tridactyla). Kittiwakes 

 were more than twice as common in SCW than in BSAW and 



ACW (Tables 2, 3). Small colonies « 10,000 individuals) are 

 found around the coastline of the entire southern Chukchi Sea, 

 whereas large colonies 010,000 individuals) are restricted to 

 Cape Lisburne, Cape Thompson, and the Diomedes (Sowls 

 etai. 1978; NOAA, 1988). 



Sabine's Gull (Xema sahini) . Small numbers of Sabine's 

 gulls were observed only in SCW and BSAW (Tables 2,3). 



Arctic Tern {Sterna panidisaea) . Ten arctic terns were 

 recorded in SCW near Station 45 (Table 2; Frontispiece). This 

 location is not far from a small breeding colony on Kolyuchin 

 Island (NOAA, 1988) near the western edge of the study area. 



Common Murre(L'naflfl/ , gf ) and Thick-billed Mune(L'nfl 

 lonivia) . Abundances of murres showed a trend of increasing 

 abundance from west to east when unidentified individuals and 

 both species were combined (Table 2). Thus, ACW had the 

 highest murre densities: 3.5 birds km - versus 2.6 and 1 .3 birds 

 km ' in BSAW and SCW, respectively. The at-sea abundances 

 parallel the distribution of colonies from which murres probably 

 originate. Only small colonies (< 100,000 individuals) are 

 located on the Soviet (western) side of the Chukchi Sea, 

 whereas two large colonies ( 100,000-1,000,000 individuals) 

 are situated at the eastern end of the study area in Alaska at Cape 

 Lisburne and Cape Thompson (Fig. I: NOAA, 1988:Sowls 

 etal., 1978). Withineach water mass type, there was generally 

 a decrease in murre abundance with increasing distance from 

 land and colony of probable origin. Largest numbers were 

 counted near Stations 49, 50, and 51 (< 1 20 km from the Cape 

 Lisburne colony) and near Stations 60 and 61 (<100 km from 

 colonies at and east of Cape Serdtse Kamen: Fig. I ). 



KinVitz' ^MurTeleHBraclixrampliitsbrevirosiris) . Four of 

 these murrelets were seen together on 1 5 August in BSAW near 

 Station 74 (Frontispiece). Although very uncommon in the 

 Chukchi Sea, this alcid breeds north to Pt. Hope, Alaska, and 

 is casual in northeastern Siberia (AOU, 1983). 



Parakeet Auklet iCxclorrhxnchu.s psittaciila) . Three 

 parakeet auklets were counted between Stations 73 and 74 in 

 BSAW (Frontispiece). This location is <65 km from the 

 closest of several colonies at Cape Dezhnev on the western side 

 of Bering Strait (NOAA, 1988). 



Least Auklet {Aeihiapusilla) . Least auklets were far more 

 abundant in BSAW than SCW and ACW (Table 2). Except for 

 a few individuals near Stations 50, 55, 58, and 6 1 (Frontispiece ), 

 greatest numbers were in the southern portion of the Chukchi 

 Sea between Stations 72 and 75. This latter location is 

 85-95 km from the closest colony on Little Diomede island, 

 where the breeding population of least auklets numbers just 

 under 1,000.000 birds (Sowls et al.. 1978). 



Crested Auklet (Aeihia cristatella) . Crested auklets 

 occurred t)nly near Station 73 in BSAW (Table 2: Frontispiece). 

 A breeding colony of 140,000 birds is located 85 km south at 

 Little Diomede Island (Sowls ei al.. 1978). 



Tufted Puffin {Fraiercula cirrhata) . Tufted puffins were 

 unrecorded in SCW and on the western side of the southern 

 Chukchi Sea (Tables 2, 3). Single birds only were observed 

 near Stations 49, 50, and 72-75. As few as 100 individuals of 

 this puffin species breed north of Bering Strait, mostly near 

 Capes Lisburne and Thompson in northwestern Alaska (Sowls 

 etai. 1978). 



385 



