432 



Fishery Bulletin 88(3). 1990 



Table 1 



Effects of 60-day exposure to mercury on blood of windowpane flounder Smphthabnus aquosus in Long Island Sound. 

 Values are mean ± standard error, with number of samples in parentheses. Number of samples is often fewer than that 

 of fish exposed because of clotting or pooling of samples. 



MCV = Mean corpuscular volume 



MCH = Mean corpuscular hemoglobin 



MCHC = Mean corpuscular hemoglobin concentration 



•Significantly different from controls (P<0.05). 



Advanced 3L osmometer; the effect of the added hepa- 

 rin on osmolahty was negligible. Plasma sodium, potas- 

 sium, and calcium concentrations were measured with 

 a Coleman 51 flame photometer. At times it was neces- 

 sary to pool the small plasma samples, resulting in 

 slightly fewer samples for plasma ions and osmolality. 

 Mean corpuscular volume (MCV), mean corpuscular 

 hemoglobin (MCH), and mean corpuscular hemoglobin 

 concentration (MCHC) were determined using the 

 following equations (Piatt 1969): 



MCV in M'Vcell = 10 Hct/RBC 

 MCH in pg/cell = 10 Hb/RBC 

 MCHC in g/00 mL packed red cells 



100 Hb/Hct 



Statistical differences were determined by one-way 

 analysis of variance and the Scheffe test (Hicks 1973). 



Results 



Exposure studies 



Results of the 60-day exposure of windowpane flounder 

 to mercury are summarized in Table 1. Red blood cells 

 in the species appear to be unaffected by mercury at 

 the test concentrations used in this study. Control 

 flounder had a mean hematocrit of 22 + 1.3%, a mean 

 hemoglobin of 4.1 ± 0.2 g/100 mL, and a red cell count 



Reference to trade names does not imply endorsement by the Na- 

 tional Marine Fisheries Service. NOAA. 



of 2.4 + 0.17 X 10'' cells/mnr^ Following a 60-day ex- 

 posure of the fish to 5 or 10 ^g/L mercury, none of these 

 variables differed signficantly from control values, nor 

 did the indices calculated from the three variables 

 (namely, MCH, MCV, and MCHC). The mean plasma 

 sodium level in flounders exposed to 10 uglL mercury 

 was 199 + 3.3 mEq/L, significantly higher than the con- 

 trol value of 179 ± 3.9 mEq/L. Plasma calcium de- 

 creased from the control value of 4.95 mEq/L to 

 3.91 ± 0.18 and 3.60 + 0.19 m/Eq/L in animals exposed 

 to 5 and 10 fxgIL mercury, respectively. There were no 

 significant differences between controls and mercury- 

 exposed flounder in plasma potassium or osmolality 

 (Table 1). 



No significant difference was demonstrated between 

 controls and animals exposed to either concentra- 

 tion of cadmium or copper in any of the parameters 

 measured. 



Field study 



The data from each season were divided by sex and 

 compared using the Scheffe test; no significant sex- 

 related differences were noted. The data were grouped 

 into four size-classes (<20.0 cm, 20.1-25 cm, 25.1-30.0 

 cm, >30 cm) and compared for each season; no signifi- 

 cant size-related differences were noted during any 

 season. Because of the lack of differences, data from 

 both sexes and all size-classes are shown together. 



Overall, windowpane flounder taken from Station 3 

 had significantly higher hematocrits and hemoglobin 

 concentrations than did those taken from Station 1. 



