Carls and Rice: Oil-exposed Theragra chalcogramma embryos 



31 



Table 3 



Distribution of individual aromatic hydrocarbons in water-soluble fractions of Cook Inlet crude oil during an 18-day static exposure 

 (1-21 day treatment) of walleye pollock eggs. Concentrations are means of three replicates measured by gas chromatography. 



Hydrocarbon 



days 



4 days 



18 days 



benzene 



toluene 



ethylbenzene 



m- and p-xylene 



o-xylene 



mesitylene 



naphthalene 



2-niethylnapthalene 



1 -methylnapthalene 



2. 6-dimethylnapthalene 



1 , 4-dimethylnapthalene 



1, 2-dimethylnapthalene 



Total mononuclear aromatics 



Total dinuclear aromatics 



Total mono- and dinuclear aromatics 



Percent total hydrocarbons remaining 



Median lethal concentrations (LCr,,,) and median 

 concentrations causing abnormalities (ABr,,,) were cal- 

 culated with logit analysis (Berkson 1957) or Spearman- 

 Karber analysis (Hamilton et al. 1977), corrected by 

 control response (Abbott 1925). 



Results 



Test conditions 



Monoaromatic hydrocarbons were initially predomi- 

 nant in the static WSF tests (89%), but they declined 

 significantly more rapidly than diaromatic hydrocar- 

 bons (P« 0.001) (Table 3). After 18 days monoaroma- 

 tics comprised only 26% of the remaining hydrocarbons 

 (Table 3). The rate of total aromatic hydrocarbon loss 

 from solution was not linear; rates were rapid initial- 

 ly, but slowed over time. Approximately one-half of the 

 hydrocarbons were lost in the first 10 days. Concen- 

 trations reported in this paper are based on initial 

 values. 



Lethal effects 



Egg survival and hatching success were slightly reduc- 

 ed (up to 17%) by exposure to WSF (Table 4). Reduc- 

 tion in survival and hatching success was significant 

 in the 1-21 day treatment, but not in the 0-21 day and 

 7-21 day treatments. Mortality after hatch was strong- 

 ly dependent on concentration (Fig. 1) and began to 

 differ significantly from controls 29 days after fertiliza- 



tion, or about 10 days after hatch. The LC51) was 

 2.2 + 0.8 ppm 10 days after hatch and stabihzed at 

 1.8 + 0.6 ppm 16 days after hatch. 



Growth 



Exposure to WSF before blastopore closure slowed 

 early embryonic development. Blastopores in control 

 embryos closed earlier than in embryos exposed to 

 WSf'(> 1.65 ppm) in the 0-21 day treatment (Table 5). 

 Embryos in the 1-21 day treatment tended to have 

 larger diameters at high WSF concentrations, but 

 diameters were highly variable (Table 6). Pore diam- 

 eters at 2.7 ppm were significantly greater than con- 

 trol diameters, but were significantly smaller at the 

 lowest concentration (0.4 ppm). After blastopore clos- 

 ure, embryonic development in the upper concentra- 

 tions could not be distinguished from control develop- 

 ment, and the time of hatch was not influenced by 

 exposure to WSF (Fig. 2). 



Yolk and body lengths of larvae that hatched from 

 eggs in the 0-21 day and 7-21 day treatments were 

 significantly reduced by exposure to WSF (P<0.03 

 [untransformed ANOVA]). (Lengths were not 

 measured in the 1-21 day treatment.) Yolk lengths 

 were reduced a maximum of 9%, total body lengths 

 were reduced a maximum of 23% (Fig. 3), and the yolk- 

 to-length ratio increased a maximum of 20%. Mean yolk 

 lengths at concentrations >2.8 ppm were significant- 

 ly (P<0.05) smaller than controls. Reductions in lar- 

 val body length in both treatments overlapped closely 



