Figure 2.--Unimak Pass and vicinity. 



1962. Fur seals were observed and collected 

 in the area from late May through early 

 October in order to obtain information on 

 migration, food habits, and behavior. 



According to the Coast Pilot,* the current 

 in Unimak Pass is probably strongest between 

 Scotch Cap Light and Ugamak Island where 

 at the peak of flood or ebb the average velocity 

 is about 3 knots. The maximum velocity may 

 exceed this at the time of tropic tides when 

 6-knot currents during the flood and 6 1/2- 

 knot currents during the ebb are to be ex- 

 pected. The current has a large diurnal con- 

 stituent which at the time of tropic tides may 

 cause the current to set continuously in a flood 

 direction for as long as 18 hours. The set of 

 the flood i s 295° true and of the ebb 105 ° true. 



* United Slates Coast Pilot 9, Alaska, Cape Spencer 

 to Arctic Ocean. 1955. 6th ed. U.S. Department of 

 Commerce, Coast and Geodetic Survey, Washing- 

 ton, D.C., 673 p. 



The current along the south shore of the 

 Alaska Peninsula and the Aleutian Islands sets 

 to the westward and drifts through the passes 

 into the Bering Sea. Along the north side of 

 the Aleutian Islands the current sets easterly. 



Tide rips off Billings Head, Akun Island, 

 are particularly noticeable at flood tide and 

 off the east end of Ugamak Island at ebb tide. 

 Tide rips are found in the northern approach 

 to the pass on the flood and in the southern 

 approach on the ebb. Wind and seas coming 

 against the current have a pronounced effect 

 on the tide rips. 



The southern approach and entrance to 

 Unimak Pass is relatively shallow (30-50 

 fathoms), but in the pass proper is a basin 

 with depth of 50-100 fathoms. The northern 

 entrance has depths of 40-50 fathoms, deepen- 

 ing to over 100 fathoms within 10 miles to 

 the northwestward. 



