PEARCY and HANCOCK; FEEDING HABITS OF FOUR FLATFISH SPECIES 



Table 6. — The average percent by weight that major taxa com- 

 posed of the diet of rex sole, slender sole, and Pacific sanddab at 

 Stations 7, 6, and 2. 



Rex sole 



Slender sole 



Pacific 

 sanddab 



6 (Table 6). A larger percentage of crustaceans 

 (and the lowest percentage of annelids) was found 

 at Station 7 than at 2 or 6 for both rex and slender 

 soles. But crustaceans were more abundant in the 

 diet of sanddab at Station 6 than at Station 7. 

 Fishes (included as other taxa) were an appreci- 

 able part of the sanddab diet at Station 7. Again, 

 differences in availability of food taxa apparently 

 occurred among stations for the same predator 

 species, and different trends in the importance of 

 food taxa are evident for different species offish at 

 the same stations. 



The principal prey were most similar for rex sole 

 at Stations 2 and 6, as were the major taxa by 

 weight. The polychaete Nothria geophilifonnis 

 and the larvacean Oikopleura occurred in over 59^ 

 of the observations only at these two stations. It is 

 curious that the planktonic Oikopleura was so fre- 

 quent in the diet of this primarily benthophagus 

 fish. Other prey common at all these stations in- 

 cluded the polychaete Goniada brunnea, uniden- 



tified polychaetes, gammarid amphipods, and 

 cumaceans. 



PandaluH jordani was a principal prey species 

 for slender sole at Stations 6 and 7 but not at 

 Station 2. The shrimp Sp/ro/Jtoca/v's hiapinosa and 

 unidentified fish were found in over 5r/c of the fish 

 only at Station 6. Copepods were common only at 

 Station 7. 



Euphausia pacifica was a principal prey for 

 Pacific sanddab at Stations 6 and 7. Pandalusjor- 

 dani occurred in 2&7( of the fish at Station 6, but 

 was uncommon at Station 7. Decapod crab larvae 

 and copepods, on the other hand, were common 

 prey only at Station 7. 



Variations With Seasons or Size of Fish 



Changes in the relative proportions of the major 

 taxa of food consumed by different sizes of the four 

 species of flatfishes are shown for "summer" 

 (May-September) and "winter" (October- April) in 

 Figures 2-5. Because food habits as well as sizes of 

 fishes vary among stations (Tables 3, 6; Pearcy 

 1978), geogi'aphic effects are confounded in these 

 figures. 



Annelids usually dominated the diet of all size 

 groups of these juvenile Dover sole during both 

 seasons (Figure 2). Crustaceans appeared to de- 

 crease in importance with increasing size of fish 

 during the winter season, but reached peaks in the 

 summer. Mollusks iSolegasters spp., Yoldia ensif- 

 era, and unidentified pelecypods) attained peaks 

 in the diet of intermediate-sized (200-300 mm) 

 Dover sole, and echinoderms (mainly ophiuroids) 

 attained a peak at a larger size of fish. 



100 



NUMBER OF FISH 

 rej (3) (12) (27) 136)120) (11) (I) (7) (10) (5) (15) (22) (14) (I) (I) 



I I I 

 100 200 300 400 



1 I r 



(WINTER) 



/ . v6 / \ 



^-. 



2/ 



/ 

 ; 

 / 



\ .1 





V / \ ' 



\ / 



V 



Figure 2. — The percent by wet weight of the 

 major food taxa for different length groups of 

 Dover sole for summer and winter. 1 = crusta- 

 ceans, 2 = annelids, 3 = other taxa, 4 = mollusks, 

 5 = echinoderms, and 6 = coelenterates. 



100 200 300 400 



STANDARD LENGTH (mm) 



645 



