were occasionally eaten, but did not constitute a 

 major component of the diet. Copepods were 

 present in 12 stomachs, but were in low numbers 

 and probably were not very important as a 

 dietary item. Fish scales were taken from 11 

 stomachs. The scales did not appear to come 

 from other fish collected in the same net hauls 

 and may indicate that these small-toothed juve- 

 niles consume scales floating free in the water. 

 One fish stomach contained a piece of a squid 

 tentacle, further suggesting that these fishes 

 occasionally act as scavengers by picking up 

 debris from predation events. 



This reliance on Phronima as the dominant 

 food organism is notable because of the 

 parasitoid relationship between the Phronimi- 

 dae and gelatinous zooplankton. Laval (1980) 

 summarized the data known about this relation- 

 ship and showed that Phronima spp. generally 

 mature and live within the bodies of pelagic salps 

 and siphonophores. Both the hosts and the 

 amphipods are virtually transparent, and ex- 

 ceptional visual acuity is probably necessary to 

 locate these prey. Traces of the hosts were not 

 found in the fish stomachs, indicating that the 

 fish either rapidly digest the host, pick the 

 amphipods from the host, or eat the amphipods 

 while the amphipods are moving between the 

 hosts. 



The inshore fishes caught in 1981 consumed a 

 more varied range of prey (Table 1). Copepods 

 were the most important prey item and were 

 found in 18 of the 20 stomachs analyzed, in 

 numbers ranging up to 184 copepods per 

 stomach. Fish larvae were another important 

 component of the diet and were found in 13 

 stomachs. These larvae ranged from tiny (2-3 

 mm) unidentifiable fish to 20 mm flatfish larvae 

 (Hippoglossoides sp.). Up to 19 larvae were taken 

 from a single stomach. Juvenile and a few adult 

 euphausiids (Euphausia pacifica and Thysan- 

 oessa spinifera) were taken from 10 stomachs, 

 in numbers up to 35 euphausiids per stomach. 

 Unlike the oceanic specimens, the inshore fish 

 rarely ate hyperiid amphipods and never 

 consumed fish scales. 



The dietary differences observed between the 

 offshore and inshore collected specimens are an 

 expected feature that reflects the availability of 

 different prey taxa in different environments. 

 The offshore stations had blue, clear water of 

 relatively low particulate content, while the in- 

 shore stations were influenced by higher coastal 

 productivity as well as river and estuarine input. 



The 1981 juveniles were collected in the transi- 

 tion zone between the oceanic and coastal en- 

 vironments. Utilization of this ecotone perhaps 

 enabled these fish to take advantage of a portion 

 of the coastal productivity and yet remain in a 

 relatively clear oceanic habitat. 



Acknowledgments 



I would like to thank W. W. Wakefield, J. 

 Fisher, and the captains and crews of the fishing 

 vessels Flamingo, Kristen Gail, and Soupfin for 

 their assistance in collecting the specimens. I 

 also thank R. Brodeur and W. Pearcy for their 

 comments on the manuscript and A. Kendall for 

 his data on egg distributions. This research was 

 made possible by funding provided by the Oregon 

 Department of Fish and Wildlife, Oregon State 

 Sea Grant College Program, Oregon Aqua 

 Foods Inc., Crown-Zellerbach Inc., and Ana- 

 dromous Inc. 



Literature Cited 



Fitch, J. E. 



1964. The ribbonfishes (Family Trachipteridae) of the 

 eastern Pacific Ocean, with a description of a new 

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 Hart, J. L. 



1943. Katsuwonus and Trachipterus in British Colum- 

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 Hubbs. C. L. 



1926. The metamorphosis of the California ribbon fish 

 Trachypterus rex-salmonorum. Pap. Mich. Acad. Sci., 

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 Laval, P. 



1980. Hyperiid amphipods as crustacean parasitoids 

 associated with gelatinous zooplankton. Oceanogr. 

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 ROEDEL. P.M. 



1938. Notes on the ribbon-fish, Trachypterus rex- 

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1923. The occurrence of Trachypterus rex-salmonorum 

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 Walker. E. T. 



1953. Records of uncommon fishes from Puget Sound. 

 Copeia 1953:239. 



Jonathan M. Shenker 



School of Oceanography 

 Oregon State University 

 Con-all is. OR 97331 



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