SHERBURNE: ERYTHROCYTE DEGENERATION IN HERRING 



three large vacuoles. The affected mature cells 

 were rounded instead of the usual oval (Figure 

 3) ; a typical rounded mature cell measured 10.1 

 X 9.4 [x for the cytosome, 3.7 x 3.4 jx for the 

 nucleus, and 1.2 x 1.5 yu, for the inclusion body. 

 Vacuolization of the cjrtoplasm was evident in 

 many red cells. Inclusions were present in some 

 microcytic mature erythrocytes as small as 

 4 X 4 /i for the cytosome (less than one-half 

 normal size). Inclusions in a few early poly- 

 chromatics were larger than usual. One of the 

 largest inclusions in a young cell was nearly as 

 large as the cell nucleus — the cytosome measured 

 9.2 X 8.0 /Lt, the nucleus 4.7 X 3,7 ix, and the 

 inclusion 3.9 x 3.6 jx (Figure 4). Otherwise 

 inclusions in the wild herring of March and July 

 were of the same size. 



A relationship appears to exist in the occur- 

 rence of inclusions and abnormal red cell mor- 

 phology with temperature extremes. The short- 

 term captive herring sampled on 22 July at 16°C, 

 the highest temperature at which samples were 

 taken, were markedly different from all other 

 samples in their morphology and incidence of 

 inclusions. Ninety-six percent (24/25) of the 

 herring had inclusions, and of those over half 

 had inclusions in at least 90% of their red cells. 



A majority of the smears in this sample showed 

 5% or less intact immature red cells. Anucleat- 

 ed "balloon" cells were evident in all smears in 

 this sample, some smears had up to 50% of these 

 cells (Figure 5). The balloon cells appear pale 

 red with Wright's stain, are similar in size, and 

 range from 9.4 x 9.4 fx to 10.9 X 10:9 /a. Some 

 of the cells appear to show diffusion of nuclear 

 material into the cytoplasm. The smears with 

 the greatest incidence of inclusions generally 

 had the most balloon cells. The most heavily 

 affected herring from the 8 July sample also 

 showed these cells. In the smear free of in- 

 clusions a few balloon cells were seen, the intact 

 cells appeared normal and 10% immature red 

 cells were present (Figure 6). Such balloon 

 cells are seen in apparently normal blood samples 

 only occasionally and in very low frequency. 



The short-term captive herring sampled on 

 21 August at 14°C showed a substantial decrease 

 in inclusions with 12% of the sample affected, 

 but many nonaffected fish had abnormal cells 

 (Figure 7) . Higher than normal seawater tem- 

 peratures of up to 20.5°C (68.9°F) during Au- 

 gust may account for the abnormal cells in her- 

 ring without inclusions. 



Inclusions were found in 2 of the 50 herring 



Figure 3.-8 July 1969. Photomi- 

 crograph of wild herring blood show- 

 ing intracytoplasmic inclusions asso- 

 ciated with nuclear degeneration and 

 a ballooning of the red cells. 



129 



