FISHERY BULLETIN: VOL. 76. NO. 3 



Oregon, and included rex sole as a benthophagus 

 species and Pacific sanddab as a piscivorous- 

 pelagic feeder. 



Rae (1956, 1969) .studied the feeding habits of 

 the lemon sole, Microstomas kitt, and the witch, 

 Glyptocephalus cynoglossus, off Scotland. Some of 

 his results are remarkably similar to ours for the 

 congeneric Dover sole, M. pacificus, and rex sole, 

 G. zochirus. Both the witch and lemon sole, like 

 the Dover and rex soles, feed predominantly on 

 polychaetes. Crustaceans were next in importance 

 followed by other phyla such as mollusks, 

 echinoderms, and coelenterates. Ophiuroids and 

 anthozoans were also eaten by both lemon sole and 

 the witch. These similarities in diets indicate 

 common feeding specializations within pleuronec- 

 tid genera. 



Although the major food of the lemon sole and 

 witch were very similar, these two species, like the 

 Dover and rex soles, preyed on different families or 

 different genera of the same family so that food 

 overlap, and presumably competition, are rare 

 (Rae 1956, 1969). As pointed out by Rae, these 

 differences in feeding habits reflect behaviorial 

 differences of the fishes as well as differences in 

 the composition of the benthic communities of 

 which these fishes are a part. The habitats of the 

 lemon sole and witch often differ, the lemon sole 

 preferring hard, rocky bottoms, and the witch soft, 

 muddy bottoms. 



Both the lemon sole and witch fed most heavily 

 during the summer. Regional differences were 

 also marked. Polychaetes decreased in importance 

 as prey for the witch in shallow water ( < 100 m), as 

 they did in our study for Dover sole (Table 3). Rae 

 (1939, 1956) also believed that differences in the 

 types and quantities of food available between one 

 area and another resulted in different growth 

 rates of lemon sole. Sedentary polychaetes were 

 most common as prey in areas of rapid growth. 



One of the objectives of this study was to learn if 

 differences in the availability of prey for flatfishes 

 occurred and how it may be related to sediment 

 types and water depth at our stations. The compo- 

 sition of prey of Dover sole clearly varies among 

 stations. Polychaetes were the main food at the 

 three deepest stations; echinoderms, coelenter- 

 ates, and polychaetes were similar on a weight 

 basis at the two 102-m stations; polychaetes, fol- 

 lowed by mollusks, were most important at the 

 100-m station; and mollusks and crustaceans were 

 most abundant at the 74-m station (Table 3). 

 Based on the percentage by weight of major food 



taxa, higher similarities occurred among stations 

 at similar depths rather than with similar sedi- 

 ment types: Stations 15 and 23 at 102 m and the 

 deep stations 6, 2, and 8 at at 148-195 m (Table 4). 

 Sediment texture at Stations 15 and 23 were dis- 

 similar. (See Figure 1 for summary of depth and 

 sediments for the stations.) Although Station 2 

 had an average sediment texture that differed 

 from Stations 6 and 8, a thin layer of silt overlaid 

 coarse sand at Station 2, hence the surface sedi- 

 ment of Stations 6, 2, and 8 were probably more 

 similar than indicated in Figure 1. 



The occurrence of individual species of poly- 

 chaetes consumed by Dover sole is probably a more 

 sensitive indicator of station differences than the 

 biomass of major taxa. Stations 7, 15, and 23, at 

 100-102 m, but with different sediment types, 

 were most similar in polychaete prey. Stations 2, 

 6, and 8 in deep water, at 148-195 m were again 

 similar. Thus, these similarities in prey for these 

 two groups of stations seem to be correlated with 

 depth. However, polychaete prey at Station 2 ( 190 

 m) was similar to that of Station 7 (100 m), which 

 had similar sediment type, as well as that at Sta- 

 tions 15 and 23 ( 102 m) with different sediments. 

 Stations 22 and 15 with similar sediment types, 

 but at different depths, had low similarity of 

 polychaete prey. 



Based on 82 species of mollusks, cumaceans, and 

 ophiuroids sampled in O.l-m^ Smith-Mclntyre 

 grabs, Bertrand ( 197 1 ) calculated the similarity of 

 the fauna among the same seven stations included 

 in this study. He also found that Stations 2, 6, and 

 8 formed a deep-water group of high similarity. 

 Stations 7 and 23 (at 100-102 m) were similar, as 

 were Stations 7 and 8, with different depths and 

 sediment types. Gunther (1972) also calculated 

 similarities among these same stations based on 

 living benthic foraminifera and found that strong 

 faunal affinities crossed depth and sediment 

 boundaries. Again, Stations 2, 6, and 8 formed one 

 group. Stations 2 and 7, and 15 and 22, station 

 pairs based on sediments, were not very similar. 



Similarities among the fishes caught were also 

 strong among Stations 2, 6, and 8. The remaining 

 stations (7, 15, 22, and 23) formed another group of 

 high affiinity (Pearcy 1978). These two species 

 associations agree with those described by Day 

 and Pearcy (1968) for the continental shelf off 

 central Oregon. They found a shallow (42-73 m) 

 water association on a sand bottom dominated by 

 Pacific sanddab and English sole, Parophrys vet- 

 iilus, and an association at 119-159 m on a silty- 



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