STEVENS AND ARMSTRONG: CANCER M AGISTER IN GRAYS HARBOR 



TABLE 2. — Mean densities of Cancer magister in Grays Harbor, 

 Wash., areas and seasons compared by ANOVA. Values are 

 means of original data expressed as crabs ha -1 , ± SE, with n 

 in parentheses. F tests were performed on log-transformed 

 data. 



Mean densities: 



Results of F-tests: 

 Companson 



Seasons 



Areas 



Interaction 



Outer harbor 

 (sites 2-4) 



Inner harbor 

 (sites 7-9) 



df 



1/83 

 1/83 

 1/83 



F-value 



15.181 

 6744 

 0607 



Season 

 means 



Probability 

 level 



0.001 

 0.011 

 0.438 



site in May 1982, and at a similar site in stratum 

 14 in May 1981, revealed that first instar crabs 

 were abundantly distributed on the mudflats at 

 low tide in slight depressions, buried just beneath 

 the sediment surface and in burrows of Cal- 

 lianassa spp. Estimated densities were 1-5 crabs 

 nr 2 , based on random visual observations within 

 an area of the mudflats measuring about 100 m 2 . 

 This density was 1-2 orders of magnitude greater 

 than that calculated from trawl catches of this age 

 group. Therefore, it is likely that 0+ crabs were 

 grossly underrepresented in the trawl catch, espe- 

 cially at stations near mudflats such as 4 through 

 8. The 0+ age group formed <1% of the catch at 

 station 1 and were virtually absent from the ring 

 net stations (10-12). 

 Crabs in the 1+ age group were by far the most 



o 



D 

 «J 



«/> 

 O 



-C 



E 



3 



o 



r 1 



m 



m 



MAY 1980 

 N =373 

 fiN=74.44 

 90 



_m 



L^ft 



16 MRY 1980 

 490 

 MERN=69-52 



T>u-n-L MERN=69.52 



r Tl ru. m MEF)N=48. 



Ti fil 11 HTrnmrmTnTrmmrn ntfe-Bi 



4 JUNE 1980 

 = 290 



MERN=48.46 

 44 



iThhr-rTI 1 1 Ml iTTTfTTTTTTfTTl 



16 JUNE 1980 

 N =295 

 in HERN=60-23 



fflmTflrftfrifn 3 



^.TTMTjfflffl I [fllHTTmrfU^ rh s n°-g : 



30 JULY 1980 

 N =146 

 MEflN=61.89 

 28-41 



Hi] 



14 RUG 1980 

 N =613 



rrrrhm : 



MERN=70-12 



5.D 



12 SEPT 1980 



rfTTTMTIIMlTi^HTTi 



=219 

 MERN=61 .53 

 S-0.=21.88 



21.39 



29 RUG 1980 

 N =176 

 n _r-Tl rh-ITU MERN=71 .53 



^mM'Tki^WinrM; 27 - 19 



nriTn rriHilTllTTm 



13 OCT 1980 

 N =45 

 HERN=68-95 

 S.D.=16.67 



27 OCT 1980 

 N =8 

 HEAN=40.25 

 S.D.=30.I8 



JU n n 



M 



>rfTh 



12 NOV 1980 

 N =142 

 MERN=77.71 

 S.D.=16.21 



r^ 



-H- 



n^ril 



rtfHTTTTTMTh 



15 0EC 1980 

 N =133 

 HERN=75.1 

 S-D. =18-94 



rfH>in n 



DB 



12 MAY 1981 

 N 



1 



Qfl 



MN=68-19 



2 JULY 1981 



M 



N 



= 351 



Wmm, 



MEflN=58-37 

 S-D-=25-40 



n il n~n 



I 1 1 1 1 1 1 1 1 1 I 1 



15 30 45 60 75 90 105 120 135 150 165 



— i  i i i 1 i i i i i 



15 30 45 60 75 90 105 120 135 150 165 



Carapace Width in 3 mm Intervals 



FIGURE 4. — Carapace width frequencies of all crabs caught by trawl at stations 1-9 in Grays Harbor, Wash., 1980-81. Numbers 

 expressed as log 10 (catch + 1). Box for each sampling period shows date, number of crabs measured, mean carapace width overall (mm), 

 and standard deviation. 



475 



