FISHERY BULLETIN: VOL. 71, NO. 4 



Table 1. — Wild herring (obtained from commercial 

 fishermen's catches.) 



Table 2. — Captive herring (held in a tank at the Boothbay 

 Harbor Laboratory prior to collection of blood samples.) 



Range 



Length 



(cnn) 



Weight 



(g) 



direct heart puncture with a heparinized capil- 

 lary tube. A small drop of blood from the capil- 

 lary was placed on a microscope slide and the 

 smear made. Slides were air-dried and stained 

 by either the Wright's or Wright-Giemsa staining 

 method. Distilled water was used as a diluent 

 for the Wright's and Giemsa stains. The air- 

 dried film was covered with Wright's stain for 

 IV2 min, then an equal quantity of distilled 

 water added and the film further stained for 

 3-4 min; then, either the diluted stain was 

 flooded off with water and the slide dried, or the 

 slide counterstained with diluted Giemsa for 20 

 min. Staining times varied slightly with different 

 batches of Wright's stain. Each herring was 

 measured for total length, weighed, sexed, 

 marked, examined for gross parasitism, and 

 frozen for reference in case abnormal blood 

 properties were found. Cells were examined 

 under oil immersion at 800 and 1,250 powers. 



Differential counts were made of both red and 

 white cells on an area of the slide where the 

 cells were evenly distributed. A leukocyte differ- 

 ential count was made of a random selection of 

 100 leukocytes and listed under the following 

 categories: lymphocytes, thrombocytes, neutro- 

 phils, eosinophils, or basophils. The range and 

 mean percentage of each type of leukocyte pres- 



ent was calculated for each sample. An erythro- 

 cytic differential count was made of a random 

 selection of 100 red cells and divided into 

 mature or immature cells based upon their gen- 

 eral morphology and staining properties. I clas- 

 sify herring erythrocytes in the peripheral blood 

 according to the stage of development as erythro- 

 blasts, early polychromatics, mid-poly- 

 chromatics, late polychromatics or mature cells. 

 These terms were used by Lucas and Jamroz 

 (1961) in describing the developmental stages 

 of avian erythrocytes. The developmental stages 

 for herring erythrocytes are described in Table 3. 

 There are variations in individual herring in the 

 size and shape between and within cell stages, 

 and the amount of polychromasia present is 

 the best indicator as to the stage to which the 

 cell belongs. The primary morphological criteria 

 I used in this paper were those of Boyar (1962). 

 Additional references were consulted for a more 

 definitive classification of cell types, to clarify the 

 distinction of basophils from basophilic-staining 

 immature erythrocytes, and to resolve confusion 

 regarding the existence of monocytes in herring 

 blood. These additional references were Catton 

 (1951), Davidsohn and Nelson (1969), Jakowska 

 (1956), Lucas and Jamroz (1961), Saunders 

 (1968b), and Watson, Shechmeister, and Jack- 

 son (1963). 



Table 3. — Erthrocytes in the peripheral blood of Atlantic 

 herring, Clupea harengus harengiis, according to the 

 stage of development. 



Stage 



Description 



Erythroblast 



Early polychronnatic 



Mid-polychromatic 

 Late polychromatic 

 Mature erythrocyte 



Round cell, similar in size to the early poly- 

 chromatic. Has a dark blue staining cyto- 

 plasm with lightly stained spaces. The round 

 purple-red staining nucleus is larger than 

 that of the early polychromatic and takes up 

 most of the cell. Erythroblasts are scarce in 

 normal samples. 



The smallest immature red cell that is nor- 

 mally seen in any quantity. Has a light 

 blue to gray staining cytoplasm and appears 

 round. The nucleus takes up most of the cell. 

 Round to slightly oval cell with a gray to 

 light gray-orange staining cytoplasm. Cell 

 is larger than the early polychromatic. 

 Slightly oval, has a larger cytoplasm and a 

 smaller nucleus than the mid-polychromatic. 

 The cytoplasm appears light orange-yellow. 

 Oval, has a slightly larger cytoplasm and a 

 slightly smaller nucleus than the late poly- 

 chromatic. The cytoplasm appears orange- 

 yellow to reddish. Late polychromatic and 

 mature erythrocytes have essentially the 

 same appearance with Wright's and Wright- 

 Giemsa stains. 



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