FISHERY BULLETIN: VOL. 71, NO. 4 



in 1971. Incidence of infection increased with 

 host age. Mean incidence of C. niacarovi infec- 

 tions was 12.8% off Oregon and 35.0% off 

 Washington in 1970 and also decreased in 1971 

 to 5.5% off Oregon and 12.9% off Washington. 

 Infection rates were independent of host size 

 and age. The incidence of scars resulting from 

 previous copepod infections was very high. Mean 

 incidence of R. cololabis in 1970 was 78.0% off 

 Oregon and 48.3% off Washington and decreased 

 substantially during 1971. Infection rates were 

 independent of host size and age. Trunk length 

 measurements increased the known length 

 range for both male and female worms. 



R. cololabis was also identified in steelhead 

 trout, which is reported as a second definitive 

 host. It seems most likely that both hosts are 

 infected through a common food organism 

 carrying the acanthor stage although steelhead 

 trout are known to feed on saury in ocean 

 waters. 



For aesthetic reasons, presence of copepod 

 parasites or scars, and to a lesser extent the 

 acanthocephalan, would undoubtedly limit 

 usage of saury in the round as a fresh fish 

 product for human consumption. Saury infected 

 by the obnoxious appearing Pennella sp. and 

 those with multiple infections of C. macarovi or 

 numerous scars, would undoubtedly be rejected 

 by consumers. Although western Pacific saury 

 are not infested by Pennella sp., Nishimura 

 (1964) reports that saury heavily blemished by 

 C. macarovi have a lower commercial value than 

 nonblemished fish. The acanthocephala are not 

 as unsightly as either copepod, although the 

 bright orange worms are often clearly visible 

 protruding from the anus. 



Considering apparent annual and age depen- 

 dent changes in incidence of infection, only 30 to 

 60% of the market-sized saury occurring in 

 Washington-Oregon coastal waters appear to 

 be acceptable as a fresh-food fish sold in the 

 round. Although some geographical variations 

 of infection rates and occurrence of scars have 

 been noted, the percentage of fish usable as a 

 fresh product appears nearly equal off Washing- 

 ton and Oregon. 



Test packs prepared by the Pacific Fishery 

 Products Technology Center, National Marine 

 Fisheries Service, Seattle, have indicated that 



these parasites have practically no effect on 

 canned saury products. Acanthocephala are 

 removed with the vicsera, and C. macarovi can 

 be scraped free with resulting wounds and old 

 scars presenting no qualitative or aesthetic 

 problems. Uninfected portions of saury with 

 pennellids can also be used. 



Pe}inella sp. and C. macarovi were also 

 employed as racial indicators by comparing 

 their occurrence between fish displaying spring- 

 and autumn-born growth patterns on their 

 scales. Seven of eight chi-square tests showed 

 no significant differences (0.05 level), between 

 fish of the two scale features; thus, evidence 

 from the parasite data does not indicate the 

 existence of separate populations. Although use 

 of parasites as biological indicators is not a 

 strong test of population structure, particularly 

 without knowledge of the parasites' life history, 

 biochemical and growth studies likewise do not 

 indicate existence of two genetically isolated 

 populations (Hughes, see footnote 2). 



ACKNOWLEDGMENTS 



I thank Paul L. Illg, Professor of Zoology, 

 University of Washington, for confirming 

 identification of the copepods, and Clyde M. 

 Senger, Professor of Biology, Western Washing- 

 ton State College, for his cooperative work on 

 the acanthocephalan and review of this 

 manuscript. 



LITERATURE CITED 



Baeva, O. M. 



1970. Nekotorye osobennosti zarazhennosti para- 

 zitami Tikhookeanskoi sairy - Cololabis suira (Some 

 features of infection of Pacific saury, Cololabis 

 saira, with parasites). //; Voprosy morskoi para- 

 zitologii: Materialy I-go vsesoyuznogo simposiuma 

 po parazitam i boleznyam morskikh zhivotnykh, 

 Sevastopol, 1970 (Problems of marine parasitology: 

 Materials from the 1st All-Union Symposium on 

 Parasites and Diseases of Marine Organisms, 

 Sevastopol, 1970), p. 3-5. Izd. "Naukova Dumka", 

 Kiev. 



Eberhardt, R. L. 



1954. Observations on the saury (Cololabis saira) 



seen near the California coast during 1950-52. 



Calif. Fish Game 40:39-46. 

 Ellis, I., and S. E. Hughes. 



1971. Pacific saury — A progress report. Natl. Fish- 

 erman Yearb. Issue 1971, 51:67-70, 75, 77, 84-85, 92. 



952 



