Piatt and Naslund 



Chapter 28 



Abundance, Distribution, and Population Status in Alaska 



Sitkadilak Strait; along the Alaska Peninsula: Halo Bay, 

 Kukak Bay, Wide Bay, and the Shumagin Islands. In the 

 Aleutians, small numbers are found at Unalaska, Adak, and 

 Attu islands, and other large islands in the chain. 



Murrelets are most abundant in sheltered "inside waters", 

 which includes bays, fiords, and island passes located in 

 coastal areas of the northern Gulf of Alaska (fig. 2). The 

 distribution of the majority of murrelets surveyed at sea 

 coincides spatially with the terrestrial distribution in Alaska 

 of coastal old-growth coniferous forests especially Sitka 

 spruce (Picea sitchensis) and hemlock (Tsuga spp.) (USDA 

 Forest Service Alaska Region 1991, 1992; Viereck and Little 

 1972), which are used for nesting by murrelets (Naslund and 

 others 1993, Quinlan and Hughes 1990). Ship-based studies 

 of lower Cook Inlet conducted in 1992 (Piatt 1993) suggest 

 that waters subject to strong tidal mixing provide poor foraging 



habitat for murrelets compared to stratified coastal waters 

 (fig. 3). Marbled Murrelet distribution in summer may be 

 determined largely by the spatial co-occurrence of terrestrial 

 breeding habitat and suitable marine foraging areas. 



During the breeding season, low densities of murrelets 

 (possibly nonbreeders) may be found in outside waters (>50 

 km from shore). Excluding these offshore birds during the 

 breeding season, Piatt and Ford (1993) found that only 3.1 

 percent of all murrelets were distributed outside the range of 

 coastal coniferous forests in Alaska (i.e., west of and including 

 the Alaska Peninsula). It appears that murrelets disperse to 

 the south and west in winter, as numbers decline in sheltered 

 northern Gulf waters, but increase offshore, along the Alaska 

 Peninsula, and in the Aleutians (table 1). Murrelet populations 

 in Prince William Sound diminish by about 75 percent in 

 winter (Klosiewski and Laing 1994). 



MARBLED MURRELET 

 5 10 15 20 



Nautical Miles 



Cook Inlet 



Birds/km2 

 0-1 Birds/km2 

 1-2 Birds/km2 

 2-4 Birds/km2 

 -8 Birds/km2 

 -16 Birds/km2 

 16-32 Birds/km2 

 100 m contour 

 130 m contour 



Kachemak 

 Bay 



Shelikof 





Figure 3 Distribution of Marbled Murrelets in lower Cook Inlet during July, 1992 (from Piatt 1993). 



288 



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



