Piatt and Naslund 



Chapter 28 



Abundance, Distribution, and Population Status in Alaska 



Murrelet Abundance 



Piatt and Ford ( 1 993 ) estimated the abundance of regional 

 murrelet populations (table 1) by extrapolating from coarse- 

 scaled OCSEAP data. The population estimate for the Northern 

 Gulf of Alaska (table 7) is undoubtedly an underestimate 

 because of poor sampling of Prince William Sound and 

 Cook Inlet. Repetitive small-boat surveys conducted in Prince 

 William Sound after the Exxon Valdez oil spill yielded summer 

 (July) population estimates (20 percent) of 107,000, 81,000, 

 and 106,000 Brachyramphus murrelets in 1989, 1990, and 

 1991, respectively (Klosiewski and Laing 1994). Averaging 

 these estimates, and subtracting the proportion that were 

 Kittlitz's Murrelets (ca. 10 percent), suggests that about 

 89.000 Marbled Murrelets use Prince William Sound in 

 summer. Ship-based surveys conducted in lower Cook Inlet 

 in summer, 1992, suggest that about 18,000 Brachyramphus 

 murrelets may be found in a 50 km radius of the Barren 

 Islands; with high concentrations along the Kenai Peninsula 

 and near Shuyak Island in the Kodiak Archipelago (Piatt 



1993; fig . 3). Small-boat surveys in 1993 of a larger area in 

 lower Cook Inlet (fig. 4) suggest that about 60,000 

 Brachyramphus murrelets use this area during summer ( Agler 

 and others 1994). 



The OCSEAP estimate for murrelet populations 

 throughout the entire Kodiak Archipelago in winter (table 1) 

 is similar to the estimate (15,000-20,000) given by Forsell 

 and Gould ( 1 98 1 ) for wintering populations of Brachyramphus 

 murrelets in selected bays of Kodiak and Afognak islands. 

 Reflecting an influx of post-breeding birds, winter populations 

 are higher (table 1) and birds appear to move into more 

 sheltered bays and fiords. Summer and winter populations 

 concentrate in different areas (figs. 5 and 6). 



No other published regional estimates are available for 

 comparison with the OCSEAP data. Mike McAllister 

 conducted hundreds of surveys throughout much of the 

 northern Gulf of Alaska between 1 983 and 1 99 1 . Based on a 

 preliminary examination of his data (McAllister, pers. comm.), 

 he made the following summer population estimates: 



-'BERS : r BRACH (RA 



}ASED SURVEY OF LOWER COOK INLET 

 JUNE, 1993 



Figure 4 Distribution of Marbled Murrelets in lower Cook Inlet during June, 1993 (from Agler and others 1994). 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



289 



