. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering 922 Microbiology 184° 182° 180° 178=. 59' 58' 57= 56' 55' 54' 53° 52' 8/16 catches 50% 21/345 fish 18/29 catches 62% 183/2282 fish 3% 187/1554 fish / 12% «.^. >3 -'^ I L J I I L_ J U 54° 53° 52° 180° 178° 176° 174° 172° 170° 168° 166° 164 162° 160° 158° 156° Figure 55-4. The general distribution and frequencies of cod with pseudobranchial tumors in the Bering Sea. tumor-bearing cod were about 25 percent shorter than normal cod of the same age. The pseudob
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering 922 Microbiology 184° 182° 180° 178=. 59' 58' 57= 56' 55' 54' 53° 52' 8/16 catches 50% 21/345 fish 18/29 catches 62% 183/2282 fish 3% 187/1554 fish / 12% «.^. >3 -'^ I L J I I L_ J U 54° 53° 52° 180° 178° 176° 174° 172° 170° 168° 166° 164 162° 160° 158° 156° Figure 55-4. The general distribution and frequencies of cod with pseudobranchial tumors in the Bering Sea. tumor-bearing cod were about 25 percent shorter than normal cod of the same age. The pseudobranchial tumors of pollock and cod were grossly similar in color, shape, and texture (McCain et al. 1979) (Fig. 55-5). However, the pollock tumors often protruded less, tending to extend up into the roof of the pharynx, and unlike cod, ten pollock had unilateral tumors. One pollock was found to have on the outside of the operculum a secondary tumor which had originated from an invasive pseudobranchial tumor. In general, these tumors were smaller than those of cod, ranging up to 35 X 20 X 10 mm. The microscopic anatomy of these tumors was much like that described for the same condition in Pacific cod (Alpers et al. 1977b), with the following exceptions: (1) granulomas common to Pacific cod tumors were not seen in pollock; (2) the fibrous stromata of the pollock tumors contained numerous melanophores, whereas melanophores were seldom observed in the stromata of Pacific cod tumors; and (3) the pollock tumors, unlike Pacific cod tumors, usually had a marked infiltration of macrophages and lymphocytes. In catches from the Bering Sea, percent of the pollock had pseudobranchial tumors. Tumor-bearing pollock were distributed in a pattern very similar to that of cod with tumors (Fig. 55-6), with the widest distribution and highest frequency in the south central area. Of the hauls in which pollock were cap- tured, 45 percent contained pollock with tumors, and the
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