FISHERY BULLETIN: VOL. 82, NO. 3 



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FIGURE 3. — Crab density for all sampling sites in Grays Harbor, Wash., sampled in 1980-81. 

 Trawl sampling sites 1-9 are shown as crabs ha~ '; ring-net sampling sites 10-12 are shown as 

 crabs per ring net. Each point represents a single sample. 



Age-Structure of Crab Population 



Width-frequency distributions for all crabs 

 caught by trawl in the estuary are presented by 

 sampling week in Figure 4. Width limits for each 

 age class were selected so as to be nonoverlapping 

 (Table 3). 



The distribution of crabs within the estuary var- 

 ied with age group. Animals in the 0+ age group 

 were commonly found from station 2-8 at an aver- 



age of 46 crabs ha -1 , and represented 16.6% of 

 total crabs caught in the estuary throughout the 

 entire 14-mo sampling period (Fig. 5). The greatest 

 annual mean density of this age group occurred at 

 station 5 near an area of dense eelgrass. The den- 

 sity of this age group was very low during 

 October-December. 



Summer populations of 0+ crabs were about 

 twice as dense at station 5 than at any other (Fig. 

 6). Visual inspection of mudflats adjacent to this 



474 



