FISHERY BULLETIN: VOL. 85, NO. 4 



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Figure 1. — Unstained spores at x2400, (I) Kudoa paniformis (approximately 8 jj-m in size) and (2) 

 Kudoa thyrsitis (about 15 jim in size), found in the muscle of Pacific whiting. Photo by Carlo Stehr. 



be a serious limiting factor in the Pacific whiting 

 fishery. 



A joint U.S. -Canadian project aimed at taking 

 the full measure of these problems was initiated 

 in 1983. The purpose of this paper is to report on 

 the results of investigations into cooked flesh tex- 

 ture and its relationship to the intensity and type 

 o{ Kudoa infection. The paper also correlates sub- 

 jective sensory texture values with objective in- 

 strumental readings and establishes texture 

 quality profiles of fish taken in different geo- 

 graphic areas along the distribution range of the 

 Pacific whiting. Other factors, such as sex, body 

 size, and location of infection within the various 

 parts of the fish (i.e., anterior, posterior, dorsal, 

 ventral) which might influence texture quality, 

 were also examined. Finally, visual culling was 

 evaluated to determine if sorting Pacific whiting 

 infected with pseudocysts from the pack was prac- 

 tical. 



MATERIALS AND METHODS 



The sample used in this investigation consisted 

 of 579 Pacific whiting collected by National 

 Marine Fisheries Service personnel aboard the 

 chartered MV Nordfjord in 37 hauls off the 

 Pacific coast of North America, between lat. 

 37°18'N (near San Francisco) and 48°54'N (west 



coast of Vancouver Island) in the four Interna- 

 tional North Pacific Fisheries Commission 

 (INPFC) areas (Fig. 2). The fish were caught be- 

 tween 16 July and 28 September 1983, in 30-min 

 tows at depths ranging from 34 to 164 fathoms. 

 Water temperatures at the cod end ranged be- 

 tween 7.5° and 10.5°C, while surface temperature 

 ranged between 12.1° and 18.8°C. These tempera- 

 tures were somewhat warmer than those in previ- 

 ous years, due to the 1982-83 El Nifio effect 

 (Weinberg et al. 1984). The Pacific whiting catch 

 varied from 7 to 2,053 kg in the total catch of 20 

 to 2,488 kg per haul (Weinberg et al. 1984). A 32 

 mm (1 1/4") stretched mesh size cod end liner was 

 used to retain small fish. Each fish was measured 

 and sexed, individually numbered, and frozen 

 aboard the vessel. The fish samples were taken to 

 the Utilization Research Division (URD) labora- 

 tory of the Northwest and Alaska Fisheries Cen- 

 ter (NWAFC) in Seattle where they were sec- 

 tioned longitudinally and each half labeled 

 accordingly. One half of each fish was shipped to 

 the Pacific Biological Station in Nanaimo, B.C., 

 Canada, for parasitological examination, and the 

 other retained by the URD laboratory for deter- 

 mination of flesh quality. 



The parasitological methods used by the Pacific 

 Biological Station are described elsewhere 

 (Kabata and Whitaker 1986). Intensity of infec- 



746 



