APPENDIX B 

 HEMATOLOGICAL CORRELATIONS IN ESTUARINE FISH 



1 . Introduction . 



Red blood cell count, microhematocrit (packed blood cell volume), and 

 hemoglobin concentration in fish blood have been estimated by several ana- 

 lytical techniques (Hesser, 1960; Anthony, 1961; Larsen and Snieszko, 1961; 

 Larsen, 1964; Summerfelt, Lewis, and Ulrich, 1967; Berinati and Crowley, 

 1972) . From these parameters other useful hematological indexes may be 

 calculated, such as mean microhematocrit and hemoglobin content of individ- 

 ual red blood cells (Wintrobe, 1956; Holton and Randall, 1967). 



Several attempts have been made to establish predictive correlations 

 between microhematocrit and red blood cell count or. hemoglobin concentra- 

 tion in both marine and freshwater teleosts (Eisler, 1965; Summerfelt, 

 Lewis, and Ulrich, 1967; Houston and DeWilde, 1968). A highly predictive 

 regression of microhematocrit with red blood cell count and hemoglobin con- 

 centration may enable workers to derive useful hematological data from a 

 single microhematocrit measurement without red blood cell enumeration and 

 hemoglobin determination. 



Houston and DeWilde (1968) showed that an estimate of microhematocrit 

 for the rainbow trout, Salmo gairdneri, may be used to predict red blood 

 cell counts and hemoglobin concentration in routine assessments of hema- 

 tological status. However, the prediction was not sufficiently exact for 

 research purposes. 



2 . Materials and Methods . 



Hematological data were taken from five species common to the Patuxent 

 River estuary: White perch, Morone amerioana; striped bass, M. saxatilis; 

 spot, Leiostomus xanthurus; hogchoker, Trineotes maautatus; and menhaden, 

 Brevoovtia tyrannus . Male and female fish from each species were used to 

 study hematological response to suspensions of mineral solids (Sherk and 

 O'Connor, 1971). Fish were captured by otter trawl from the Patuxent 

 River estuary. Blood samples were taken from both the control fish and 

 the fish exposed to sublethal concentrations lof fuller's earth. The data 

 represent hematology of fish under normal laboratory conditions (18 ±1° 

 Celsius, salinity 5.5 parts per thousand), and fish under stress from 

 suspended sediment. 



Blood was collected in heparinized pipets and mixed before analysis. 

 Microhematocrit was determined according to methods outlined by Hesser 

 (1960), and was read on an International Equipment Company microcapillary 

 reader. Hemoglobin was determined by the cyanmethemoglobin method. Sam- 

 ples were centrifuged at 11,500 revolutions per minute for 20 minutes to 

 remove red cell nuclei from suspension before taking a reading (Larsen, 

 1964). Optical density of the hemoglobin samples was determined at 540 



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