FEEDING HABITS OF DOVER SOLE, MICROSTOMUS PACIFICUS; REX SOLE, 



GLYPTOCEPHALUS ZACHIRUS; SLENDER SOLE, LYOPSETTA EXILIS; AND 



PACIFIC SANDDAB, CITHARICHTHYS SORDIDUS, IN A REGION OF 



DIVERSE SEDIMENTS AND BATHYMETRY OFF OREGON 



William G. Pearcy and Danil Hancock* 



ABSTRACT 



The feeding habits of the Dover sole and rex sole (mainly juveniles) and of slender sole and Pacific 

 sanddab were investigated at seven stations on the continental shelf off central Oregon. Dover sole had 

 a catholic diet, feeding on a large variety of infaunal and epifaunal invertebrates. The composition of 

 the diet varied among stations of different depth and sediment type indicating opportunistic feeding. 

 Pelecvpoda were the most important prey on a weight basis at the shallow station (74 m) of well-sorted 

 sand where they were the dominant macrofaunal invertebrate. Ophiuroids, sea pens, anemones, and 

 pelecypods were the most important prey at 100-102 m stations of silty sand or sandy silt. Polychaetes 

 composed over 90^^ of the diet at the deep stations ( 148-195 m) of clayey silt or silty sand. The average 

 standing stocks per square meter of Dover sole caught in beam trawl collections and polychaetes in 

 grab samples were positively correlated among stations. 



Similarity of the food habits of Dover sole on the basis of food weight or frequency of occurrence was 

 generally higher among stations of similar depth than of similar sediment texture. Similar trends were 

 noted for assemblages of benthic fishes and invertebrates. 



Dover sole collected during the winter had the highest percentage of empty stomachs, the fewest prey 

 taxa. and often the lowest frequency of occurrence of prey taxa within a size group. Because seasonal 

 variations were not observed in abundance of macrofaunal food in the sediments, availability of prey 

 may change with season, or more likely, Dover sole feed more intensely and less selectively during 

 summer. 



Small ( <150 mm standard length) rex sole fed mainly in amphipods and other crustaceans. Large 

 (150-450 mm standard length) rex sole preyed chiefly on polychaetes. The diet of rex sole was less 

 diverse than that of the Dover sole and overlap of diet between the two species was not large. 



Both the Pacific sanddab, numerically the most common species offish at the shallow sand station, 

 and the slender sole, the most common species at the three deep, soft-sediment stations, preyed 

 principally on pelagic crustaceans such as euphausiids, shrimps, and amphipods. Although the 

 biomass of mollusks in the sediments was large at the shallow sand station, they were not consumed by 

 Pacific sanddab. Fish were occasionally an important food for the sanddab. 



The objectives of this study were: 1) to describe the 

 food habits of the four species of flatfishes that are 

 common in trawl catches on the central continen- 

 tal shelf off Oregon: Dover sole, Microstomas pac/- 

 ficus. rex sole, Glyptocephalus zachirus, slender 

 sole, Lyopsetta exilis, and Pacific sanddab, 

 Citharichthys sordidus; 2) to evaluate the possible 

 effects of depth and sediment, size of fish, and 

 season of capture on their food habits; and 3) to 

 compare the biomass and composition of fish food 

 from grab samples with feeding habits of fishes. 

 These species are among the most abundant 

 flatfishes in demersal communities of this region 

 of the Pacific Ocean ( Alverson et al. 1964; Day and 



'School of Oceanography, Oregon State University, Corvallis, 

 OR 97331. 



Pearcy 1968; Alton 1972; Demory and Hosie^). 

 They dominated the fish catches at the stations 

 where they were captured for this study ( Pearcy 

 1978). In order to know more about the role of 

 these fishes in their ecological communities, in- 

 cluding competitive-predatory relationships, 

 more data are required on their food habits. 



Hagerman (1952) listed food items found in 

 Dover sole caught in California waters. Pearcy 

 and Vanderploeg ( 1973) listed general taxonomic 

 groups preyed upon by Dover, rex, and slender 

 soles and Pacific sanddab. Kravitz et al. (1977) 

 gave a detailed account, including species of prey 



Manuscript accepted .January 1978. 

 FISHERY BULLETIN: VOL. 76 NO. .3. 1978. 



^Demory, R. L., and M. J. Hosie. 1975. Resource surveys on the 

 continental shelf of Oregon. U.S. Dep. Commer., NOAA, Natl. 

 Mar. Fish. Serv., Commer. Fish. Res. Dev. Act, Annu. Rep. July 

 1, 1974 to June 30, 1975, 9 p. 



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