FISHERY BULLETIN: VOL. 79. NO 4 



all depths; however, this result may be due to 

 net avoidance by larger larvae near the surface in 

 the daytime. These results are similar to those 

 found for Atlantic w^hiting, in which larger larvae 

 spread upward to 15 m at night. 



Butterfish 



An overall mean of 41 eggs/100 m^ was caught 

 during the cruise, making butterfish eggs third in 

 abundance (Table 1). Fewer eggs were caught at 

 the greatest sampling depths though the eggs at 4 

 m slightly outnumbered those at the surface 

 (Table 4). In addition, more eggs were taken at 

 night, which could reflect an evening spawning 

 time. No significant differences in the number of 

 eggs taken from day to day was evident. 



An overall mean of 50 butterfish larvae/100 m^ 

 was taken during the cruise. There were no 

 significant differences in numbers of larvae over 

 the 3 d or during day as opposed to night (Table 2), 

 indicating that we were probably sampling a 

 uniform concentration of larvae throughout the 

 experiment. In general, more larvae were taken at 

 15 m, but the diel-depth interaction indicated that 

 the larvae were more abundant in the and 4 m 

 nets at night than during the day. This pattern is 

 similar to that of Gulf Stream flounder and 

 fourspot flounder indicating that some of the 

 larvae that spend the day in the thermocline move 

 toward the surface at night (Figure 3). The second 

 experiment indicated that the 2 m catches were 

 highest at 1800 h while the 15 m catches were high 

 at all other times. 



Fourspot Flounder 



Fourspot flounder eggs ranked fourth in abun- 

 dance, with a mean of 36 eggs/100 m^ taken 

 during the cruise (Table 1). Fewer eggs were taken 

 at the greatest sampling depths though similar 

 numbers were taken at and 4 m and at 15 and 30 

 m (Figure 5, Table 4). No significant differences 

 between day and night catches were evident. 



An overall mean of 46 fourspot flounder larvae/ 

 100 m^ was taken. The catches were significantly 

 different for all three primary factors, i.e., more 

 were caught at night than in the daytime, more 

 were caught on day 3 than on the first 2 d, and the 

 15 m tow took more than the other three (Table 2). 

 The interaction between days and depth was 

 significant because on day 2 the surface and 4 m 

 tows had high catches relative to the other days, 



while on day 3 the 15 and 30 m tows had high 

 catches relative to the other days. Apparently the 

 drogue, which was centered in the upper 10 m of 

 the water column, did not experience the same 

 drift during the experiment as the fourspot floun- 

 der larvae, which had their center of abundance in 

 the thermocline at a depth of 15 m. The day-night 

 depth interactions indicated migration by some 

 larvae toward the surface at night since the and 

 4 m tows had high catches at night while the 15 

 and 30 m tows had high catches during the day 

 (see Figure 3). 



Results of the second experiment show the same 

 pattern in that more larvae were caught at night 

 and the 15 m tow had high catches at all times. 

 However, the 0, 2, 4, and 6 m tows had relatively 

 higher catches at night than during either of the 

 day periods. 



These results indicate that fourspot flounder 

 larvae occur mainly in the upper part of the 

 thermocline where temperatures are above 10° C. 

 Those larvae that move from 15 m during the day 

 to near the surface at night, pass from 18° C water 

 to 22° C water. The salinity also changes over this 

 depth range from about 33.61, at 14 m to 32.81, at 

 the surface. 



Hakes 



The species of hake ( Urophycis ) eggs and larvae 

 in our samples could not be determined because of 

 overlapping meristic characters and spawning 

 seasons, so more than one species may be repre- 

 sented. An overall mean of 27 eggs/100 m^ was 

 taken, making hake eggs fifth in abundance. 

 Slightly more eggs were taken at 4 m than at the 

 surface (Figure 5), but otherwise egg numbers 

 decreased with increasing depth (Table 4). No 

 significant differences between day and night 

 catches were evident, indicating that the daily 

 spawning time was prolonged, or that we were 

 possibly sampling more than one species with 

 somewhat different spawoiing times. Egg concen- 

 tration in the area of the drogue remained fairly 

 constant. There were no significant differences 

 among the 3 sampling days. 



An overall mean of 146 larvae/100 m^ was 

 taken, making hakes the most abundant larvae 

 caught (Table 1). In general, they were most 

 abundant at 15 m (Table 2), but more were taken 

 in the and 4 m nets at night, and more in the 15 

 and 30 m nets during the day (Figure 3). During 

 the second experiment, the time-depth interaction 



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