FISHERY BULLETIN: VOL. 72, NO. 2 



four were taken during the day at 500-625 m. 

 Melanostomias spp. (23; 48-238) were mostly 

 taken at 50-250 m at night or 520-800 m during 

 the day. Due to either damage to the barbels 

 (mostly Leptostomias) or lack of data on the varia- 

 bility of characters used to separate nominal 

 species in these genera, definite identifications 

 cannot be given. 



Idiacanthidae 



Idiacanthus fasciola (341; 13-375 mm) 



Larval /. fasciola (13-50 mm) were taken 

 mostly at night in the upper 200 m; deeper catches 

 both day and night were scattered and probably 

 contaminants. Males (30-50 mm) were taken prin- 

 cipally between 550 and 800 m during the day. 

 Fourteen of the 20 night captures were also in the 

 day depth range, but 6 were taken at 200-300 m. 



At night, females (47-375 mm) were taken prin- 

 cipally between 30 and 300 m. All taken below 200 

 m were over 145 mm, but larger ones did occur 

 shallower. In the December 1970 series seven 

 females were taken, but only one was taken at 

 night in the upper 300 m, the remainder were 

 taken within the day depth range. During the day, 

 females were taken mostly between 600 and 800 

 m, but one was caught at 250 m and several at 

 400-600 m. Too few were taken to make detailed 

 comparisons of day and night catch per effort, but 

 the data indicated no gross differences in abun- 

 dance or size frequency. 



Female /. fasciola mature at about 250 mm, 

 but too few large individuals were taken to assess 

 any seasonal trends in gonad ripeness. There were 

 no clear seasonal trends in size composition of the 

 catches. Larvae and males were taken most fre- 

 quently in December. Few were taken in March, 

 with catches for June, July, and September inter- 

 mediate. In July, September, and December, 84- 

 91% of the females were shorter than 150 mm, 

 while the percentages for March {597c ) and June 

 (30% ) indicated relatively fewer smaller females. 

 There were, however, no definite size groups 

 which could be traced from season to season. 



Malacosteidae 



Fhotostomias guernei (159; 24-158 mm) 



Photostomias guernei was taken principally at 

 346 



15-300 m at night and at 350-800 m during the 

 day. A few specimens were taken in deep night 

 tows with the opening-closing trawl indicating 

 that the entire population does not regularly mi- 

 grate. Small fish were caught throughout these 

 ranges, but only two fish over 100 mm were caught 

 above 185 m at night and none over 80 mm were 

 taken above 750 m during the day. 



Mature female P. guernei showed a rather curi- 

 ous size distribution. Of 41 females examined 

 (46-158 mm), 11 bore ripened ova. Nine were 

 64-85 mm and two were considerably larger — 147 

 and 158 mm. Of the specimens with undeveloped 

 ova, seven were less than 63 mm, and the remain- 

 der 93-149 mm. Some of the large individuals 

 could possibly have spawned already, but the in- 

 dividuals between 93 and 125 mm were clearly 

 immature. The bimodal size distribution suggests 

 that two populations were present in the samples, 

 but there was considerable overlap or agreement 

 in photophore and fin ray counts of both large and 

 small females. Also there was no indication that 

 one type of female had a different depth distribu- 

 tion or seasonal pattern than the other. 



Photostomias guernei probably spawns over 

 most of the year. Individuals under 40 mm were 

 most frequently taken in June, but were present 

 in all series. There was no obvious seasonal trend 

 in size composition of the larger fish. 



Aristostomias spp. 



Aristostomias lunifer (12; 30-151 mm) was 

 taken only between 120 and 260 m at night. The 

 largest specimen, a 151 mm female, was mature or 

 nearly so. Aristostomias grimaldii (5; 33-117 mm) 

 was taken at 100 and 500 m at night and at 690 

 and 750 m during the day. The largest specimen, a 

 male, appeared immature. Aristostomias poly dac- 

 tylus (10; 33-140 mm) was taken at 100, 175, 320, 

 and 590 m at night and at 625, 850, 875, and 1,100 

 m during the day. The largest individual was an 

 immature female. Two specimens similar to A. 

 tittmanni (68 and 75 mm) were taken at 15 and 

 250 m at night. 



Malacosteus niger (133; 26-186 mm) 



Malacosteus niger occurred between 520 and 

 900 m during the day and 500-850 m at night; the 

 day-night differences were due to sample spacing. 

 Most were taken between 600 and 700 m. The 



