FISHERY Bl'LLKTIN: VOL. 74. NO. :i 



Among 19 specimens that could be sexed, there 

 were 8 males and 11 females. The seven largest 

 fish included two males (440 and 507 mm), three 

 apparently mature females (ca. 490-575 mm), and 

 two nearly mature females (464 and 494 mm). 



Bregmacerotidae 



Two species of the genus Bregmaceros were 

 taken in our collections. One fits published data 

 (D'Ancona and Cavinato 1965) on B. japonicus 

 Tanaka reasonably well, while the other is closest 

 to but not identical with B. macdellandi Thomp- 

 son. The latter is apparently distinct from another 

 form similar to B. maccleUandi which has been 

 taken in the southern Pacific (E. H. Ahlstrom and 

 J. E. Fitch, pers. commun.). The exact identity of 

 all of these must await a thorough review of this 

 badly confused genus. 



The two Hawaiian forms were, however, quite 

 distinct from each other. Dorsal and pectoral ray 

 counts were 56-62 and 19-21 for B. mocclelknidi vs. 

 50-54 and 17-19 (rarely 20 or 21), respectively, for 

 B. japouicus. The latter was the more slender 

 species with SL/greatest body depth of 7.3-10.0 vs. 

 6.5-7.3 in B. maccleUandi. Bregmaceros japonicus 

 adults were distinctly darker dorsally, while B. 

 maccleUandi were not countershaded. The isth- 

 mus and pelvic fins of all larger B. maccleUandi 

 were grey, while in juveniles (<25-30 mm), the 

 isthmus was covered with small melanophores. In 

 most B. japonicus the isthmus and pelvics were 

 totally unpigmented. A few small (ca. 20-25 mm) 

 specimens whose counts fit B. japonicus had a few 

 large melanophores on the isthmus. 



Bregmaceros japonicus T^iniki (284; 18-52 mm) 



The great majority of B. japonicus were taken 

 at 25-125 m at night; however, 40 specimens, 

 possibly contaminants, were taken at 125-200 m. 

 Those under 30 mm were taken mostly above 100 

 m, while larger individuals were taken with 

 roughly equal frequency throughout the 25- to 

 125-m range. Only 32 specimens were taken dur- 

 ing the day; most (25) were large individuals (>35 

 mm) and taken at 600-800 m. This suggests that 

 during the day the juveniles may occur shallower 

 than the upper limit of our day samples (ca. 300 m). 



Female B. japonicus appear to mature at about 

 40 mm, and almost all specimens over this size 

 carried well-developed ova at all seasons. Small 



fish (<30 mm) were most abundant in March; they 

 made up about 50^?^ of the catch then as opposed to 

 less than 10% at other seasons. 



Bregmaceros cf. maccleUandi Thompson 

 (274; 14-94 mm) 



Bregmaceros maccleUandi occurred between 100 

 and 250 m at night. Most individuals less than 30 

 mm were caught about 150 m, and most 30-50 mm 

 above 175 m, but larger fish were taken with 

 roughly equal frequency throughout the night 

 depth range. Day catches were mostly between 

 600 and 1,000 m with those less than 30 mm 

 occurring above 800 m. Seven specimens (65-80 

 mm) were taken in tows that fished between 1,200 

 and 1,400 m; three of these were from an open- 

 ing-closing trawl. 



Bregmaceros maccleUandi over about 35 mm 

 appear to avoid the IK. Of the total specimens, 152 

 were taken by the CT in March 1971. Of these only 

 about 12% were less than 35 mm, whereas, about 

 half of the IK specimens were less than 35 mm for 

 either the March data alone (12/23) or the total IK 

 collection (56/122). 



Females mature at about 60 mm. There were so 

 few mature females in most series that no trends 

 in gonad ripeness could be ascertained. The size 

 composition of the catch showed no obvious sea- 

 sonal changes. 



Melamphaidae 



Scopelogadus mizolepis mizolepis (Giinther) 

 (201; 7-74 mm) 



Ebeling and Weed (1963, 1973) concluded from 

 their data that S. m izolepis does not undertake diel 

 vertical migrations and gave the upper depth limit 

 of "adults" (66-94 mm) as 500 m. Our data, in 

 contrast, clearly indicate that 5. mizolepis of all 

 sizes undertake a definite vertical migration. 

 During the day, S. mizolepis occurred between 600 

 and 1,000 m and possibly deeper (the few tows 

 below 1,000 m do not allow us to guess whether IK 

 catches there were made in transit). Most of the 

 fish less than 25 mm were taken between 600 and 

 800 m, and most larger ones at 700-1,000 m. At 

 night the smallest fish occurred at 100-180 m, those 

 25-50 mm mostly at 150-250 m, and the larger ones 

 at 200-400 m. There were no night catches between 

 400 and 600 m, but several specimens of all sizes 



638 



