PEARCY and HANCOCK: FEEDING HABITS OK FOUR FLATFISH SPF.CIKS 



tified crustaceans. Kravitz et al. ( 1977) listed Not- 

 hria spp. as frequently occurring polychaetes and 

 Ampclisca macrocephola, Hippumedon wecomus, 

 Paraphoxus epistumusi?), and P. ubtusidens as 

 frequently occurring amphipod prey for rex sole. 



Crustaceans composed the bulk of the diet of all 

 sizes of slender sole during both seasons (Figure 

 4). Annelids and "other taxa" were most important 

 in the diet of intermediate-sized (101-200 mm) 

 slender sole during either summer or winter. 

 Pelagic crustaceans such as copepods, eu- 

 phausiids, and crab larvae occurred frequently in 

 the diet of small (<150 mm) slender sole, whereas 

 polychaetes, the shrimps P. Jordan i and S. bi- 

 spinusa, and fishes were important for large slen- 

 der sole (>150 mm). Again, a larger number of 

 principal prey taxa occurred during the summer 

 than winter. 



Crustaceans also were the most important taxa 

 in the diet of the Pacific sanddab, except for five 

 201-250 mm individuals during the summer, 

 when fishes composed 959^ of the food by weight 

 (Figure 5). Kravitz et al. (1977) found that all C. 

 sordidiis (90-377 mm total length) collected in 

 May off Oregon had been feeding intensively on 

 northern anchovy. Barss (see footnote 4) reported 



NUMBER OF FISH 



^2 J (15) (70) (41) (6) (7) (64) (179) (130) (7) 



lOOn 



X 



o 



>- 



GQ 



UJ 

 O 



LJ 

 CL 



(WINTER) 



STANDARD LENGTH 



Figure 4. — The percent by wet weight of the major food taxa for 

 different length groups of slender sole for summer and winter. 1 

 = crustaceans, 2 = annelids, 3 = other taxa, 4 = mollusks, and 5 

 = echinoderms. 



(3) (96)(252)(55) (5) 

 lOOr- 



NUMBER OF FISH 



(32) (46) (4) (17) (I) 



(WINTER) 



A , 





100 



200 



300 



STANDARD LENGTH (mm 



Figure 5. — The percent by wet weight of the major food taxa for 

 different length groups of Pacific sanddab for summer and 

 winter. 1 = crustaceans, 2 = annelids, and 3 = other taxa. 



that sanddab eat small fishes, squids, and oc- 

 topuses. 



Crustaceans were the predominant prey during 

 both seasons and for most sizes of sanddab. 

 Euphausiids, copepods, and cumaceans occurred 

 more frequently in small than large individuals. 

 Pandaliis jordani, crangonids, and fishes were 

 most common in the diet of large Pacific sanddab. 



DISCUSSION 



The four common flatfishes caught in this study 

 compose two generalized feeding types. Dover and 

 rex soles feed almost exclusively on benthic inver- 

 tebrates, mainly polychaetes and amphipods, 

 while slender sole and Pacific sanddab prey 

 mainly on pelagic crustaceans. The food habits of 

 these two types are related to mouth structure and 

 digestive morphology. Flatfishes that feed on 

 benthos usually have asymmetrical jaws, small 

 stomachs, and long intestines, whereas pelagic 

 feeders have longer, symmetrical jaws with sharp 

 teeth and long serrated gill rakers, adaptations for 

 grasping and retaining animals that swim in 

 midwater (Hatanaka et al. 1954; Groot 1971). 

 Dover and rex soles belong to the benthos-feeding 

 type and sanddab and slender sole to the pelagic- 

 feeding type. Kravitz et al. (1977) also recognized 

 these two feeding types among five flatfishes off 



647 



