was 0.135 nmol/mg protein in the P. stellatus, very similar to results in other species and 

 phyla. 



Induction of cytochrome P-450 content by injection of the fish in the present study with 

 BNF indicated a large potential for response in the Platichthys stellatus. Relative to controls, 

 BNF-injected fish showed a 2.4-fold increase in mean total P-450 content. In contrast, 

 Pseudopleuronectes americanus injected with BNF showed an increase in mean total P-450 

 content of 1.3-fold over that of controls (Stegeman et al., 1987). Similarly, mean EROD 

 activity (units/min/nmol total P-450) increased 4.8-fold in BNF-treated P. stellatus relative 

 to controls, whereas EROD activity in BNF-treated P. americanus changed 1.6-fold relative 

 to controls. EROD activity in the deep-sea fish Cory-phaenoid.es armatus averaged 1.175 ± 

 0.310 nmol/nmol P-450 in fish from the Hudson Canyon off New York and 0.178 ± 0.050 

 nmol/nmol P-450 in fish from the Carson Canyon off Newfoundland (Stegeman et ah, 1986). 



Mean liver microsomal cytochrome P-450 content ranged from 0.18 ± 0.05 to 0.53 ± 0.11 

 nmol/mg protein in Platichthys flesus sampled at four sites in Langesund fjord, Norway 

 (Stegeman et al., 1988). This range corresponded to roughly a 3-fold difference among sites. 

 A difference of about 14-fold (from 3.5 ± 1.6 to 47.9 ± 18.7 pmol/min/mg protein) in the 

 activity of the P-450E isozyme between the fish from the reference and contaminated sites 

 indicated that the fish were highly induced at the contaminated site. Mean EROD activity 

 in the same fish increased roughly 14-fold (from 39 ± 19 to 547 ± 236 pmoles/min/mg 

 protein) between the reference site and the most contaminated site. All three of the 

 responses (total P-450, P-450E, and EROD) paralleled the gradient in contamination reported 

 by Addison and Edwards, 1988. All three appeared to be responsive to high molecular 

 weight hydrocarbons (PAHs and PCBs) measured at the sites. None of the three was 

 particularly responsive to the low molecular weight hydrocarbons in mesocosm exposures 

 tested concurrently with analyses of feral fish. The pattern of EROD response in the 

 Norwegian flounder {Platichthys flesus) recorded by Stegeman et al. (1988) using 

 spectrophotometric methods was confirmed in the same fish by Addison and Edwards (1988) 

 using fluorometric methods. With the latter methods, a 13.2-fold difference in EROD 

 activity (range = 91 ± 41 to 1,206 ± 462 pmol/min/mg protein) was observed. 



The difference in mean total P-450 content in feral fish between the sites with the 

 highest and lowest mean values was 1.6-fold in P. stellatus (present study), 1.7-fold in P. 

 americanus (Stegeman et al, 1987), and 2.9-fold in P. flesus (Stegeman et al, 1988) (Table 40). 

 The difference in mean EROD activity (units/min/nmol total P-450) between the highest and 

 lowest sites was 4.6-fold in P. stellatus, 3.05-fold in P. americanus and 14.0-fold in P. flesus. 

 The difference in mean P-450E content among sites was 13.9-fold in P. stellatus and 13.7-fold in 

 P. flesus. 



The averages of the CVs and the ranges per average SD for four end-points are compared 

 among three species of feral flatfish in Table 42. These species of fish were likely exposed 

 to different water quality conditions in different geographic areas and were collected in 

 studies with different methods and research objectives. For all five end-points, the average 

 CVs and ranges/SDs were fairly similar among the three species, despite the differences in 

 species and geography. The average CV for cytochrome P-450E content in P. stellatus was 

 particularly high. The range per average SD was very consistent for the measures of 

 EROD/mg protein among the three species. The average CVs were also very similar among 

 the three species for AHH activity. 



90 



