be the result of direct contact of the spawned eggs with gasoline, not 

 merely a postmortem effect. At least some toxic hydrocarbons have 

 a special affinity for membranes, aromatic compounds altering the 

 surface properties of cell membranes (Roubal and Collier 1975). As 

 described below, subsequent cytological examination of the em- 

 bryos of other eggs from the same samples revealed most of them to 

 be moribund, but only a few embryos were grossly deteriorating at 

 the cell level. Similarly, upon gross examination of the intact eggs, 

 only a very negligible number appeared to be deteriorating. 

 Chorion condition will influence prospects of successful embryo 

 development. 



The chorion of another three early-stage fourbeard rockling 

 eggs, from samples taken on 18 March, 2 d after the spill, was 

 examined in the scanning electron microscope. The pattern of pores 

 characteristic of the outer egg membrane of fish' (L^nning and 

 Hagstrom 1975) was completely lacking in these samples. See 

 Figures 3-8 to 3-11. 



General morphological and cytological observations on 

 fourbeard rockling embryos from early postspill samples. — Careful 



examination, prior to dissection, of the fourbeard rockling eggs 

 from samples taken at postspill days 2 and 4, revealed most of them 

 to be partially collapsed. Very few were obviously deteriorating, as 

 noted above. A few had a greenish tinge seldom observed, and of 

 unknown significance, in fish eggs collected in plankton. 



In some fourbeard rockling eggs the yolk adhered to the em- 

 bryo to an extent not previously observed on dissecting thousands 

 of fish eggs of other species. This could have been a hardening ef- 

 fect of the gasoline on the yolk or, less likely, a normal 

 phenomenon for this species. 



In a few fourbeard rockling embryos from the second day 

 after the spill the exterior layer of embryo cells had an abnormal ap- 

 pearance. Other cells in the interior of the embryo also occasionally 

 appeared similarly abnormal. Nuclei and mitotic configurations of 

 such embryos often failed to take the stain. A few of these embryos 

 also had abnormally large intercellular spaces with an amorphous 

 material in some spaces and shrunken-appearing cells (Figs. 3-12, 

 3-13). This has never been observed in prior studies of embryos in 

 varying stages of deterioration. A few fourbeard rockling embryos 

 also had abnormally small, though normal, mitotic configurations. 



Figure 3-9. — Scanning electron microscope view of a portion of chorion of 

 fourbeard rockling egg. Membrane is deteriorating and no pore structure can be 

 observed. Postspill day 2 (10,000 x ). 



Figure 3-10. — Scanning electron microscope view of a portion of chorion of 

 fourbeard rockling egg. Membrane is deteriorating and no pore structure can be 

 observed. Postspill day 2 (25,000 X). 



Figure 3-11. — Two scanning electron micrographs (about 10,000 x ), (a) cod, Gadus callarias, chorion and (b) pollock, Pollachius virens, chorion, are examples of 

 striking pore patterns one expects to find in fish eggs. No such patterns were observable in fourbeard rockling eggs sampled in gasoline spill vicinity 2 d after spill (even 

 though embryo and egg deterioration had not occurred) as demonstrated in Figures 3-9 and 3-10. Compare Figure 3-11 with Figure 3-9 at same magnification. 



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