FISHERY BULLETIN: VOL. 7L NO. 4 



Table 5. — Blood cell measurements in microns of wild Atlantic herring, Clupea harengus harengus, with the average size, 



standard deviation, and size range (in parentheses). 



gross parasitism to distinguish them from other 

 herring in their respective samples. 



The mean percentage of immature erythro- 

 cytes varied widely between individual herring, 

 but the mean percentage of immature erythro- 

 cytes varied little between samples of wild and 

 captive herring within their respective categories. 

 Wild herring had a greater percentage of imma- 

 ture erythrocytes at each sampling than did the 

 herring held captive. Immature erythrocytes 

 in wild herring ranged from 6 to 38% with an 

 average of 21; in captive herring they ranged 

 from 2 to 22% with an average of 11. As noted 

 for other fish species (Catton, 1951; Hesser, 

 1960), films prepared from herring blood were 

 characterized by the presence of more cellular 

 debris and disintegrating cells than is usually 

 found in films prepared from mammalian 

 bloods. Erythroblasts, hemoblasts, and cells 

 showing mitotic division were scarce in the 

 peripheral blood of herring examined in this 

 study. 



DISCUSSION 



The high variability in differential counts 

 between individual herring is not unusual; such 

 variability was noted in a number of vertebrate 

 species (Altman and Dittmer, 1961:127-128). 

 Lucas and Jamroz (1961) discussed the indivi- 

 dual variability in blood values and the prob- 

 lems associated with this characteristic in avian 

 species. Rooney, Roberts, and Dexter (1972), 

 in differential counts of immature Atlantic 

 salmon, found the most individual variability 

 in thrombocytes, followed in decreasing order 

 by lymphocytes and neutrophils. 



Though I agree with Boyar (1962) in the 

 general description of cell types in herring, my 

 data differ markedly in the percentage of imma- 

 ture red cells in herring blood, in the percentage 

 of white cell types present, and in the relative 

 size of neutrophils in comparison to other white 

 cell types. I found an average of 21% immature 

 erythrocytes in 141 wild herring ranging in 



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