developing reasonably well until meeting with some extremely un- 

 favorable conditions. 



(b) Yellowtail flounder. No eggs available in samples. 



Postspill day 4, 20 March. — (a) Fourbeard rockling. On 

 postspill day 4, more fourbeard rockling eggs and eggs from several 

 additional sample stations (12) were available than on postspill day 

 2. See Tables 3-5 and 3-6. A portion of all eggs, 31/1 12 or 27.7%, 

 were at two subsequent developmental stages from those taken 18 

 March, 2 d after the spill (Table 3-6). Mortality for stages II and III 

 was 59.3% of the eggs (48/81). Mortality for the later stages IV and 

 V (gastrula and early embryo) eggs was less, 7/31 or 22.6%, as 

 might be expected for later, less sensitive developmental stages 

 (Longwell and Hughes 1980, In press). The average number of 

 mitotic telophases was 13.5 for the two earlier stages, and 18.7 for 

 the two later stages. These figures are similar to the 16.4 for the ear- 

 ly stages sampled 2 d earlier. See Table 3-6 for data on the 4 d 

 postspill fourbeard rockling eggs. 



(b) Yellowtail flounder. Only three yellowtail flounder eggs 

 were sampled at one station (208) on this date and all three were 

 moribund (Table 3-7). They were at stage VI (tail-bud embryo). 

 The average number of mitotic telophases was 10.3, as for the 

 rockling, not markedly low. 



Postspill day 25, 10 April. — (a) Fourbeard rockling. Fifteen 

 sample stations are represented in the 10 April collection of 

 fourbeard rockling eggs, three of which had fourbeard rockling 



Table 3-6. — Cytologteal-cytogenetic estimates of fourbeard rockling egg moribun- 

 dity 4 d after the Ocean 250 gasoline spill. See Figure 3-14 (map) for explanation of 

 system for designating same sample station on consecutive cruises. 



Development stage II-I1I 

 (morula-blastula) 



Development stage 1V-V 

 (gastrula-early embryo) 



Sample station Total no. No. moribund Total no. 



No. moribund 



201 

 202 

 203 

 205 

 206 

 208 

 210 

 212 

 213 

 214 

 215 

 217 



7 

 14 

 7 

 5 

 2 

 3 

 9 

 2 

 12 

 5 

 5 

 10 



Table 3-7.— CytologtaU-cytogenetic estimates of yeDowtail flounder 

 egg moribundity 4 d and 25 d after the Ocean 250 gasoline spill — all 

 stages VI (tail-bud) and Ml (tail-free) embryos, except one abnormal 

 stage ITJ or rv, In 25 d sample. See Figure 3-14 (map) for explanation 

 of system for designating same sample station on consecutive cruises. 



Time of sample 



4 d postspill 

 25 d postspill 



Sample 



Total no. 



No. 



station 



eggs 



moribund 



208 



3 



3 



10 



6 



4 



11 



1 



1 



13 



2 



2 



15 



2 



2 



18 



2 



1 



eggs on postspill day 2, and most of which had eggs on the 20 

 March sample date. See Figure 3-14. The number of fourbeard 

 rockling eggs per sample ranged from 1 to 24 (Table 3-8). There 

 were a total of 184 fourbeard rockling eggs available for analyses. 

 Mortality is here again treated by grouping of earlier and later 

 developmental stages since it is expected, on the basis of extensive 

 field data on Atlantic mackerel eggs (Longwell and Hughes 1980), 

 that it would be higher, even naturally, for the earlier stages. For 

 stages II and III moribundity was estimated to be 41.8% (33/79 

 eggs), somewhat less but not greatly different from the 59.3% of 20 

 March. For the later stages, IV- VI, the moribundity estimate was 

 24/105 eggs of 22.9%, hardly any different from the samples taken 

 on postspill day 4. 



(b) Yellowtail flounder. Five of the stations yielded 

 yellowtail flounder eggs in the plankton collected 25 d postspill. 

 There was a total of 13 eggs and 10 of these (76.9%) were moribund 

 (Table 3-7). All but one abnormal embryo about gastrulation were 

 at somewhat later development stages than most eggs in this study, 

 stage VI (tail-bud) and stage VII (tail-free). As noted above, the 

 later the development stage, the lower the normally anticipated 

 mortality. This mortality estimate is then high. 



Depressed mitotic index of postspill 25 d samples. — The mitotic 

 index taken as the average number of total mitotic telophases per 

 embryo was higher on postspill days 2 and 4 for both yellowtail 

 flounder and fourbeard rockling, early and later development 

 stages, than in was on postspill day 25. As noted above, for 

 yellowtail flounder the average number of telophases was 10.3 in 

 the 20 March sample, but only 1.8 in the 10 April sample (all late 

 stages). For fourbeard rockling it was 16.4 for early stages 2 d 

 postspill. It was 13.5 for early stages and 18.7 for later stages 4 d 

 postspill. At 25 d postspill this number was 6.8 for early stages and 

 6. 1 for later stages. Such a lowering of the rate of cell division in the 

 developing embryos of both fourbeard rockling and yellowtail 

 flounder could be attributable to 1) some interaction of 

 temperature-salinity conditions, but the water should have been 

 warming and development accelerating; 2) some deterioration of 

 water quality not related to the spill; 3) poor quality of eggs spawn- 

 ed subsequent to the spill and its dissipation due to maternal uptake 



Table 3-8. — Cytological-cytogenetic estimates of fourbeard rockling egg 

 moribundity 25 d after the Ocean 250 gasoline spill. See Figure 3-14 (map) for ex- 

 planation of system for designating same sample station on consecutive cruises. 



Development stage II-III 

 (morula-blastula) 



Development stage IV-VI 

 (gastrula-tail-bud-tail-free) 



Sample 



station 



Total no. 



No. moribund Total no. No. moribund 



1 

 2 

 3 

 4 

 6 

 7 

 8 

 10 

 11 

 12 

 13 

 14 

 15 

 16 

 18 



4 

 4 

 9 

 4 

 4 

 3 



10 

 5 

 5 

 6 



11 

 

 3 

 9 

 2 





 3 

 6 

 

 11 

 11 

 12 

 7 

 11 

 II 

 13 

 1 

 6 

 13 

 



28 



