CLARKE: ECOLOGY OF LANTERNFISHES 



Comparison of day and night series was 

 possible only for the June 1971 series due to 

 poor timing of the night samples with respect 

 to moon phase in September and December 1970 

 and inadequate coverage in March 1971. Both 

 the calculated totals and size-frequency curves 

 for June 1971 agreed quite closely. Since about 

 85% of the fish in this series were <20 mm, 

 any differences for larger fish would be difficult 

 to detect, but the other series showed no 

 obvious indications of differential day-night 

 avoidance. 



The CT caught only 4 x as many C. U'armi)igi 

 as the IK at 25 m, but outfished the IK by 

 factors of 12-14 x between 50 and 100 m. The 

 calculated CT total was 7.4 x the IK total; 

 when only fish over 25 mm were included, the 

 factor was 8.3. The size-frequency curves were 

 similar at 25 m but differed significantly for 

 the deeper tows, the CT catching larger propor- 

 tions of larger individuals. The calculated curves 

 differed similarly, even when only fish over 

 25 mm were included. Apparently, some of the 

 smaller fish passed through the CT meshes, 

 thus accounting for the differences at 25 m 

 where these fish were more abundant, but the 

 CT appeared to sample the larger fishes, par- 

 ticularly those over 35 mm, better than the IK. 



At new moon in September 1971, the depth of 

 peak abundance was at 45 m. and the majority 

 of the population was between 15 and 100 m. 

 During full moon, the peak depth was at 130 m, 

 and the population was mostly between 100 

 and 170 m. The calculated total for new moon 

 was about twice that for full moon, and the 

 new moon tows caught slightly larger propor- 

 tions offish over 35 mm. 



The calculated totals indicated that C. irarmhi- 

 gi was present in comparable numbers in 

 December 1970, March 1971, and June 1971 

 and much less abundant in September 1970, 

 but the calculated size-frequency curves differed 

 greatly (Figure 11). In June 1971, the popula- 

 tion was about 90% juveniles (14-17 mm), and in 

 December 1970, about 60% were over 40 mm with 

 few under 20 mm. In March 1971, 70% of the 

 juveniles were 20-40 mm, and in September 

 1970, most were either under 25 mm or over 

 45 mm. Changes in the numbers of juveniles 

 accounted for most of the changes in abundance. 



20 30 40 50 



STANDARD LENGTH (mm) 



Figure 1L — Cumulative size-frequency curves of Cenito- 

 scopelus WLirmingi calculated from samples taken through- 

 out the water column in September 1970 (A); December 

 1970(B); March 1971 (C); and June 1971 (D). 



but adults were definitely most abundant in 

 December 1970 and almost absent in June 1971. 

 The large numbers of immature fish in March 

 1971 (particularly, a peak at 25-30 mm) suggest 

 that some recruitment had taken place between 

 December and March. The size composition of 

 the population in June 1971 indicated a spring- 

 time spawning also. The percentage of ripe 

 females was highest in June 1971, but none of 

 the differences between series were significant. 

 It appears that C. warmingi spawns over a long 

 season, but principally during the first half of 

 the year, and that there are either peaks within 

 this season or marked fluctuations in larval and 

 juvenile mortality. 



Not OS CO pel US dtudispin osiis 



N. caudispi)iosus was captured very rarely, 

 but several fish, 20-25 mm, caught in March 

 and June 1971 suggest that it may spawn in this 

 area or nearby. It is possible that the larger 

 individuals avoid both the CT and IK and are 

 more abundant than the collections indicate. 



DISCUSSION 



Rare species 



The majority of the species collected were 

 rather rare. Only 19 species were present in 

 moderate to high abundance and showed strong 

 evidence of spawning in the area. A few of the 

 rarer species appear to have primary centers of 

 abundance elsewhere. The single Diaplius tlicta 

 collected was certainly an expatriate from North 

 Pacific transitional waters (Paxton, 1967), and 

 four species are restricted to nearshore waters 



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