FISHERY BULLETIN: VOL. 71, NO. I 



Table 4. — Species and density (number per square meter), by station, of the comiaon pelecypods. 



I 20 



2 



4 



5 



6 30 



8 30 



9 70 

 10 10 

 11 



12 



13 - 



14 - 

 15 



16 10 



17 



18 



19 



20 - 



21 



22 40 



23 



24 



25 



26 



27 



28 - 



29 



30 - 



31 



32 



33 



34 



35 - 



36 



37 



38 - 



39 - 



40 - 

 41 



42 



43 - 



44 



45 - 



46 



48 



49 



50 - 



51 - 



52 20 



53 20 



54 - 

 55 



56 80 

 57 



58 - 



59 - 



60 - 

 61 



63 



10 

 80 

 160 



130 

 40 

 40 



20 

 40 



1,560 

 30 



10 



110 



660 



10 



40 



130 



110 

 50 



10 

 20 



90 

 90 

 10 



100 

 10 



120 

 60 



10 

 50 



250 20 



170 - 150 

 30 

 10 



20 

 110 

 140 

 110 



10 

 30 



40 10 - 60 



150 2,120 160 60 

 20 10 90 160 



200 30 

 70 80 10 

 20 20 30 

 30 



10 

 30 



10 



760 



20 



70 



2,080 



40 



50 



50 

 290 



10 

 10 

 50 



280 

 40 



170 

 10 



30 

 10 



150 

 50 



80 



10 

 70 



30 

 40 



10 



30 



10 120 



10 

 10 



20 

 550 

 760 



80 



20 

 60 

 10 

 50 



250 40 



- 1,360 230 



- 1,360 250 

 10 80 



- 190 



- 240 

 40 10 



30 20 



30 



40 - - 



90 - 10 



10 

 10 

 10 



230 

 50 

 60 

 10 

 40 

 10 

 80 

 1,160 

 70 



20 

 50 

 50 

 160 



150 160 

 70 90 

 120 

 20 20 



- 350 



40 



- 360 



30 



10 

 10 



870 

 220 

 430 



20 

 190 



20 

 30 



20 

 30 



90 

 60 



- 20 

 20 20 



140 

 140 



10 

 30 



10 

 20 



10 



40 



70 

 160 150 



10 

 390 



20 

 170 

 90 



30 

 30 



10 

 10 

 30 



90 20 



10 



10 



- 120 

 10 10 360 



- 150 



- 250 

 20 50 



10 

 10 

 30 



30 

 20 

 70 



240 

 90 



10 

 130 

 330 



40 

 220 



10 



80 



110 

 20 



30 

 50 

 90 

 90 

 70 

 60 

 30 



60 

 490 



10 

 90 

 20 



30 



10 

 10 



130 60 

 30 

 920 1,340 210 

 430 - 210 



20 



50 

 30 



20 

 60 



20 



100 



40 



10 



20 

 20 

 10 



10 



220 

 1,050 

 1,000 



10 



20 

 30 



10 



10 



20 



20 - 



70 20 



40 



20 



10 

 70 



440 300 300 



100 

 20 40 30 

 20 100 20 



10 

 20 



20 

 300 

 980 



90 

 110 



20 110 



30 



- 800 



20 



20 



280 



70 120 

 200 430 



30 70 10 



20 - 60 



90 10 90 



310 3,780 290 



460 10 



350 140 



10 



20 



30 



880 



800 1,440 



150 



50 



390 



10 70 



10 



240 - 



80 - 10 



80 - 130 



20 - 10 



30 - 170 

 10 

 50 



80 

 - 180 160 

 20 10 



160 

 500 



10 

 10 



- 20 490 

 30 

 30 - 50 



- 120 



80 10 



10 30 50 



- 70 



80 

 240 4,600 



40 

 630 200 



40 



240 



30 



30 

 80 



10 10 



80 

 120 



30 

 140 



80 

 70 

 60 



Members of this group were by far the most 

 abundant mollusks. Densities were as high as 

 8,230/m- (all species combined). The occur- 

 rence records of pelecypods are presented in two 

 tables: Table 4 gives the number of shells per 

 square meter, by stations, for the 35 more com- 

 mon species and Table 5 lists the number of 

 shells per square meter for each of the 22 species 

 that occurred at only one station. Each pelecy- 

 pod shell was counted separately. No attempt 

 was made to enumerate the left and right valves 

 separately, because of the fragmentary nature 

 of many specimens. 



Distribution and Density 



Pelecypods, all species considered, were gen- 

 erally most abundant in a band extending north- 

 east-southwest across the study area and in 

 another narrower band parallel to the depth con- 

 tours near the shelf break (Figure 8) . Densities 

 were frequently less in the northwest, northeast, 

 and south-central sections of the continental 

 shelf and along the continental slope. As ex- 

 pected, the density of the group was strongly 

 influenced by a relatively few species that were 

 both abundant and widely distributed. 



10 



