FISHERY BULLETIN: VOL. 85, NO. 4 



cyst counts and 5 of 8 (63%) with black pseudocyst 

 counts fell in the 1 to 3 texture category. Al- 

 though the data are limited, this may suggest 

 that for lower counts black pseudocysts are not 

 related to poor texture, whereas for higher 

 counts, they are (r = -0.38 at P = 0.001). 



In this study, 459 out of 562 fish were infected 

 with the myxosporean parasite Kudoa . However, 

 knowing that only white pseudocysts contain the 

 parasites that produce the proteolytic enzymes 

 that adversely affect texture (Tsuyuki et al. 

 1982), the assessment of the effect of pseudocyst 

 infections on texture was necessarily confined to 

 white pseudocyst counts only. Therefore, in order 

 to determine the most likely white pseudocyst 

 count which, when exceeded, would produce an 

 abnormal texture in the cooked fish, the following 

 analysis was made. On the scale of firmness in 

 Table 1, the minimum acceptable texture value 

 was defined as 3. Only 20 fish were rated 3. Their 

 mean intensity of infection was 94.9 pseudocyst 

 counts and median intensity was 88. Conse- 

 quently, fish with median intensity >88 pseudo- 

 cyst counts were hypothesized to be abnormally 

 textured. On a qualitative scale this level of infec- 

 tion was considered heavy. To test this hypothe- 

 sis, all fish having infection intensities >88 white 

 pseudocyst counts were computer selected. There 

 were 50 such fish. These included 90.3% of all the 

 fish with abnormal textures (sensory rating of 1 

 to 2), but also included 3.9% of all the normal or 

 soft-textured fish (sensory rating of 3 to 9). Next, 

 fish with average sensory textures (5) were se- 

 lected to determine the white pseudocyst counts 

 below which sensory textures would most likely 

 be normal. The median pseudocyst count for these 

 fish was 23. Counts below 23 were considered in- 

 dications of a light infection. The level of infection 

 between these two counts (23 to 88) was consid- 

 ered to be moderate. 



Because black pseudocyst counts correlated 

 poorly with sensory texture in this study, the de- 

 gree of black pseudocyst infection had to be ar- 

 rived at from cullability figures using the culling 

 techniques described previously. The cullability 

 categories were determined visually and, like the 

 white pseudocysts, described as light, moderate, 

 and heavy. Confidence limits for black pseudocyst 

 counts for each cullability category were statisti- 

 cally determined and the midpoint between the 

 high end of one confidence limit and the low end 

 of the adjoining confidence limits was taken as 

 the dividing point. The following range of black 

 pseudocyst counts was arrived at for each cate- 



gory: none (0); light (1 to 28); moderate (29 to 79); 

 heavy (80 or more). 



Effect of Geographical Areas 



Data in Figure 6A shows the percentage of the 

 catch from the various survey areas sampled in 

 this study and their related sensory textures. 

 Based on results of our sensory evaluations, 13% 

 of the Pacific whiting harvested from the 

 Monterey-Eureka, CA, sampling areas had ab- 

 normal textures, whereas only 1 to 3% of the 

 Pacific whiting caught between the Columbia 

 River and Vancouver Island had abnormal tex- 

 tures. The correlation coefficient between survey 

 area and sensory texture rating was 0.20 at 

 P =0.001. 



Similarly, the incidence of heavy white pseudo- 

 cyst infection (>88 pseudocyst counts) was about 

 threefold greater in the Pacific whiting from the 

 Monterey-Eureka, CA, corridor (Fig. 6B) than in 

 whiting caught between the Columbia River and 

 Vancouver Island, i.e., 16 to 11% vs. 5 to 4%. The 

 percentage of no white pseudocyst found in the 

 fish samples from all survey areas ranged from 25 

 to 34%. 



The trend in black pseudocyst counts (Fig. 6C) 

 was similar to the trend in white pseudocyst 

 counts in that more heavy (>80) black pseudocyst 

 counts were observed in Pacific whiting caught 

 between Monterey-Eureka, CA, and the Colum- 

 bia River than in Pacific whiting from the Van- 

 couver Island area. Two to three percent of the 

 Pacific whiting sampled from the area between 

 Monterey, CA, and the Columbia River were 

 heavily infected with black pseudocysts, whereas 

 no heavy black pseudocyst infections were found 

 in the Pacific whiting caught from Vancouver Is- 

 land area. Infections of black pseudocysts in 

 Pacific whiting from the Vancouver Island area 

 were primarily light (1 to 29), the category into 

 which 84% of the infected fish fell, and moderate 

 infections (29 to 79), the category in which 4% of 

 the infected fish fell. 



Table 6A shows the prevalence of the Kudoa 

 species found in Pacific whiting caught between 

 Monterey, CA, and Vancouver Island, Canada. 

 Kudoa paniformis was the predominant species 

 (average 36 to 37%) found in the Pacific whiting 

 taken in the Monterey-Eureka area, whereas K. 

 thyrsitis was the predominant species (29 to 40%) 

 in the fish caught north of the Columbia River. 

 Mixed infections averaged 34% for the combined 

 survey areas. 



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