FEEDING ECOLOGY OF 0-AGE FLATFISHES AT 

 A NURSERY GROUND ON THE OREGON COAST 



E. W. Hogue and A. G. Carey, Jr. 1 



ABSTRACT 



The food habits of 0-age English sole, Parophrys vetulux; butter sole, Isopsetta isolepis; speckled 

 sanddab, Citharichthys stigmaeus; and sand sole, Psettichthya melanost ictus; were investigated over 

 a 2;4-year period at a shallow nursery area (9-30 m) off the central Oregon coast. A total of 422 guts 

 from recently metamorphosed fish (17-88 mm SL) were examined; only 16 were empty (4%). The 

 greatest similarity in diets was between English and butter soles. Both species were benthophagous, 

 feeding on a wide variety of prey, including palps of the polychaete Magelona sacculata, juvenile bi- 

 valves, siphons from tellinid clams, harpacticoid copepods, amphipods, cumaceans, and juvenile 

 decapods. Speckled sanddabs fed equally on benthic prey (amphipods, cumaceans, decapods) and 

 mysids, while sand sole almost exclusively ate mysids. The guts of all four species tended to be <25% 

 full in the morning before 0900 h; stomach fullness gradually increased during the late morning and 

 afternoon. 



Food habits of English sole were a function of location of capture within the study area, season, and 

 fish length. Juveniles <35 mm SL fed on small prey, e.g., polychaete palps, juvenile bivalves, tellinid 

 clams, and harpacticoids, while larger individuals fed on larger prey, e.g., amphipods, cumaceans, 

 and decapods. Diets of English sole <35 mm SL varied greatly both between seasons in the same 

 year and between years. Spatially, the diets of English sole captured in trawls at the same depth and 

 different depths were similar in January 1979 but highly variable in May 1979. These temporal and 

 spatial differences in feeding are probably caused by seasonal changes in the abundance and spatial 

 distributions of benthic prey. 



Many juvenile flatfishes recruit to the sea floor in 

 well-defined nursery areas following metamor- 

 phosis from pelagic larvae. The types and densi- 

 ties of food items present in such benthic regions 

 potentially can affect growth and mortality of 

 recently settled flatfish species (Paloheimo and 

 Dickie 1966; Steele et al. 1970; Cushing and 

 Harris 1973). In addition, whenever the nursery 

 grounds of several species coincide or overlap, 

 interspecific interactions originating from simi- 

 larities in diet may also be a factor regulating 

 growth and survival (e.g., Edwards and Steele 

 1968). Four species of pleuronectiform fishes — 

 English sole, Parophrys vetulus; butter sole, 

 Isopsetta isolepis; speckled sanddab, Citharich- 

 thys stigmaeus; and sand sole, Psettichthys mela- 

 nostictus— utilize the shallow water of the open 

 Oregon coast as a site of benthic recruitment and 

 early growth. All but C. stigmaeus are important 

 to the Oregon trawl fishery. English sole ranks 

 among the top three commercial species based on 

 annual landings. 



In conjunction with a long-term research pro- 

 gram designed to improve management of Ore- 



'School of Oceanography, Oregon State University, Corval- 

 lis, OR 97331. 



gon's multispecies demersal fishery (Pearcy et 

 al. 1977; Richardson and Pearcy 1977; Pearcy 

 and Hancock 1978; Laroche and Richardson 

 1979; Hayman and Tyler 1980), we examined the 

 prey selected by recently settled individuals of 

 these four species at one site over a 2%-yr period. 

 Our specific goals were to describe the food 

 habits of these fishes, to relate the temporal and 

 spatial variability of the English sole diet to 

 changes in prey abundance and distributions, 

 and finally to compare the dietary and habitat 

 overlap of English and butter soles. 



MATERIALS AND METHODS 



The area selected for this work was located off 

 Moolach Beach on the open Oregon coast ( Fig. 1). 

 Situated between Yaquina Head and Cape Foul- 

 weather 10 km north of the nearest estuary, this 

 site has been the focus of recent work on the re- 

 cruitment and growth of juvenile pleuronectids 

 (Laroche and Holton 1979; Rosenberg 1981; Kry- 

 gier and Pearcy 2 ) and the food habits of adult 



Manuscript accepted January 1982. 

 FISHERY BULLETIN: VOL. 80, NO. 3, 1982. 



2 Krygier, E., and W. G. Pearcy. Distribution, abundance, 

 and growth of 0-age English sole in estuaries and along the 

 coast of Oregon: the importance of estuarine nursery grounds. 



555 



