Shima et a\ Spatial distribution of Theragra chalcogramma in the Gulf of Alaska 



315 



Q19$4 ■1987 

 □ 1990 11993 

 B1996 



§5^ 

 S 5 



CPUE (number of fish/km2) 



Figure 6 



Porportion of stations for different density levels of adult wal 

 eye pollock. 



There was a general increase over time of low-density 

 concentrations of age-2 pollock with respect to bottom 

 depth and geographic region (Fig. 9). The increase in the 

 proportion of low-density concentrations of age-2 pollock 

 was the greatest 20-60 nmi from land until 1996, when 

 the proportion of stations with low-density concentrations 

 increased the most >60 nmi from land. 



Community composition 



Results of clustering by species by using the triennial 

 bottom trawl data are presented in Table 8. The top 30 

 species or species types (e.g. adult and juvenile pollock) 



by weight over all sui^ey years were chosen. Adult pol- 

 lock were consistently associated over the years most 

 closely with flathead sole (Table 8). The cluster containing 

 adult pollock usually included 3-6 other species of impor- 

 tance, either commercially or in terms of abundance. These 

 included arrowtooth flounder {Atheix'sthes stomias (Jordan 



