CLARKE: ECOLOGY OF LANTERNFISHES 



frequency curv'es were quite similar. The 

 agreement of numbers and curves was closest 

 for June 1971. This indicates that since the 

 night data were all from shallow tows, most, if 

 not all, of the population migrated at that time. 

 There was little point in comparing CT-IK 

 data since most fish were apparently small 

 enough to pass through the coarser CT meshes. 



50- 



20 10 20 



STANDARD LENGTH (mm) 



Figure 5. — Cumulative size-frequency curves calculated 

 for Notolychnus vuldiviae (left) from samples taken 

 during September 1970 in the upper layers at night (A), 

 near the day depth at night (B), and during the day (C): 

 and (right) from samples taken throughout the water 

 column in September 1970 (A), December 1970 (B), 

 March 1971 (C), and June 1971 (D). 



The new moon series in September 1971 

 indicated the population was mostly between 

 75 and 145 m while at full moon it was between 

 130 and 190 m. The calculated size-frequency 

 curves agreed closely, but the new moon series 

 calculated total was about 3x that of full moon. 

 This suggests that N. valdiviae occurs about 

 50 m deeper and avoids the net better during 

 full moon. The latter seems questionable since 

 even adults are quite small and unlikely to 

 avoid the trawl. Although full moon tows below 

 200 m in other series made no substantial 

 catches, it is possible that some of the popula- 

 tion was below the deepest depth sampled during 

 the September 1971 full moon series. 



Both day and night calculated totals indicated 

 that N. valdiviae was distinctly most abundant 

 in September and least so in March; the values 

 for December were slightly higher than those 

 for June. Both September series indicated large 

 proportions and numbers of smaller (<15 mm) 

 fish. A few small fish were present in March 

 and June, but in December none were < 17 mm 

 (Figure 5). The percentages of mature females 



with developed ova for March and June were 

 significantly higher than those for September 

 and December. 



Lnmpiide)iii Imuinosci 



No individuals of L. luminosa over 32 mm 

 were caught above 100 m at night, but a few, 

 16-24 mm, were taken shallower. The rest 

 of the catches, of both large and small fish, 

 were mostly between 150 and 250 m. Five fish, 

 16-18 mm, were taken during the day at 525- 

 550 m, but most day catches of all sizes were 

 between 650 and 750 m. In June 1971 and 

 July 1970, the catch was almost exclusively 

 <25 mm fish; in September these small fish 

 still predominated but there were also several 

 25- to 40-mm individuals caught. Only one 

 specimen was caught in December 1970, and 

 in March 1971, 80% of the catch was over 35 

 mm. None of the individuals captured were 

 mature, suggesting that the adults are larger 

 than the maximum size collected and likely 

 take more than 1 year to mature. 



LciDipiidenii mophcios 



L. Hvophaos was caught rather sporadically; 

 only one each was caught at night in September 

 and December 1970, and none during the day 

 in December 1970 or June 1971. All sizes 

 appeared to be present throughout the ranges 

 given. One fish 18 mm long was caught in 

 December and several <30 mm were taken in 

 March, June, and July. Otherwise, most of the 

 fish were 35-65 mm with a few individuals over 

 90 mm. One ripe female, 98 mm, was collected 

 in March. 



Tiiimingichthys hcithyphilits 



T. batiiypJiiliis was taken regularly between 

 600 and 1,000 m and occasionally deeper both 

 day and night. Highest catches were between 

 700 and 800 m. It was the only myctophid 

 which definitely did not migrate. Size composi- 

 tion of the catches was roughly similar at all 

 seasons with most individuals 30-60 mm long. 



415 



