FISHERY BULLETIN: VOL. 75, NO. 1 



TABLE 4. — Mean percent survival through hatching and yolk absorption of Pacific 

 herring larvae from eggs of benzene-exposed and control females. 



1 See Table 5 for test of significance. 



TABLE 5. — One-way analysis of variance in survival of Pacific herring embryos to hatching and 

 larvae through yolk absorption (larval day 7). Ripe females exposed prior to spawning. Five 

 replicate containers per treatment; 150 eggs/container. ( Arcsin transformation applied to percent 

 survival data.) 



Percent survival to hatching 



Source of variation 



df 



SS 



MS 



F ratio 



Probability 



Between concentrations 



vs. 800 ppb 

 Within groups 



Total 



12 



14 



1 .3442 



0.0843 

 1 .4285 



06721 



0070 



95.6098- 



P<0.01 



Although male herring were not studied in de- 

 tail here, their behavior was severely disrupted, as 

 in the females. Testes of mature, spawning her- 

 ring have been found to contain higher levels of 

 cholesterol (a lipid) during spawning than at other 

 times in their adult life (Blaxter and Holliday 

 1963), and it is possible the lipid-soluble benzene 

 may accumulate to high levels in testes of ripe 

 males. Effects on males and their spermatozoa, as 

 well as effects on females, may have contributed to 

 reduction in survival of fertilized eggs through 

 yolk absorption in these experiments. 



Reference to Figure 1 shows that the maximum 

 accumulation of labeled benzene in ovarian eggs 

 was greater than in later egg and larval stages as 

 measured in other experiments. Accumulation in 

 ovarian eggs of exposed females was approxi- 

 mately twice that in eggs exposed just after 

 spawning and prior to blastopore closure and 

 about six times that in embryos exposed just after 

 yolk-sac absorption. Accumulation for the first 48 

 h of water column exposure in these stages ap- 

 pears to correlate with the yolk volume of the eggs 

 and larvae, decreasing as yolk is utilized, as would 

 be expected with lipid-soluble benzene. However, 

 the decreased accumulation may also relate to the 

 development of enzymes enabling later stages to 

 metabolize benzene and subsequently depurate 

 more rapidly. After being fed Brachionus 



plicatilis, which accumulate high levels of benzene 

 (Echeverria 6 ), the fish larvae rapidly accumulated 

 benzene from their food (Figure 1). Other studies 

 of accumulation in tissues of adult herring (Korn 

 et al. see footnote 2) show that only one site, the 

 gall bladder with bile, accumulates higher con- 

 centrations than ovarian eggs (30 times and 14 

 times initial concentration, respectively). 



I have noted previously (Struhsaker et al. 1974) 

 that the percentage survival of eggs through 

 hatching is significantly less (approximately 25% 

 less;P<0.01) in Pacific herring eggs collected from 

 San Francisco Bay than in those from Tomales 

 Bay. Although other environmental differences 

 may be involved, this reduction in hatching suc- 

 cess may well relate to the effects of accumulated 

 pollutants in the gonads of spawning fish in the 

 relatively more polluted San Francisco Bay wa- 

 ters and warrants further study. 



Estimating that the reduction in survival of 

 eggs through yolk absorption of spawning exposed 

 females is at least 43%, the effect on Pacific her- 

 ring populations exposed to only one toxic 

 component of petroleum could be significant. 

 Considering that the total water-soluble fraction 

 contains many other toxic aromatics, it is possible 



"Echeverria, T. Manuscr. in prep. Uptake and depuration of 

 14 C benzene in the rotifer, Brachionus plicatilus. 



48 



