AHLSTROM: FISH LARVAE IN EASTERN TROPICAL PACIFIC 



species is not restricted to the central water 

 mass but also can occur in the transitional 

 waters of the Humboldt Current. Larvae of 

 this species were taken close to the Chilean 

 coast between lat 20° and 30° S on MARCHILE 

 VI, the Chilean contribution to EASTROPAC II. 

 D. atlanticus appears to be a temperate-sub- 

 tropical species, whereas D. laternatus is a 

 tropical-subtropical species. The distribution of 

 larvae of this species in the eastern North Pa- 

 cific is given in Moser and Ahlstrom (1970, figs. 

 41 and 42). A larval specimen taken at lat 6° 

 N along long 119° W shows that this species can 

 bridge the tropical gap between its areas of 

 usual occurrence in more temperate waters of 

 the North and South Pacific. 



Electrona sp. ( 33 occurrences, 74 larvae ) 



Distribution of Electrona larvae on EAS- 

 TROPAC I was limited to two bands — one cen- 

 tering on lat 5° N (6 occurrences, 16 larvae) 

 the other in the central water mass of the South 

 Pacific, between lat 8° and 20° S (27 occur- 

 rences, 58 larvae). The Electrona larvae all 

 resemble E. rissoi, although two kinds may be 

 present. 



Gonichthys tenuiculus ( Garman ) 

 (92 occurrences, 232 larvae) 



Larvae of Gonichthys tenuiculus have a sim- 

 ilar distribution in the eastern tropical Pacific 

 to those of Diogenichthys laternatus. Larvae of 

 a different species of Gonichthys (3 occurrences, 

 3 larvae) were obtained at the southern end of 

 the Rockaway pattern. Beebe and Vander Pyl 

 (1944) reported collecting more adults of G. 

 tenuiculus (re\)orted &s Myctophum coccoi (Coc- 

 co) ) , than of any other myctophid on the Arc- 

 turus Expedition to the eastern Pacific in 1925. 

 Their collections were made on adults aggregat- 

 ing at the surface. Based on larval evidence, Go- 

 nichthys tenuiculus is only moderately common. 



Hygophum atratum-reinhardti ( 1 27 occurrences, 

 887 larvae) 



Larvae of these two species are similar in ap- 

 pearance and difficult to distinguish at some 



stages of larval development. Larvae of Hygo- 

 phum atratum (Garman) were distributed over 

 much of the EASTROPAC pattern; however 

 some occurrences at the southern end of the 

 patterns of Rockaway, Jordan, and Argo were 

 referable to H. reinhardti (Lutken). 



Hygophum proximum Becker (116 occurrences, 

 898 larvae) 



Hygophum proximum is a truly oceanic spe- 

 cies, not occurring at all in the inner pattern 

 worked by Alaminos, and it was most abundant 

 in the outer pattern occupied by A7-go (Fig. 

 10). It occurs in the central water masses of 

 the North and South Pacific, but also in the 

 equatorial current system; the largest collection 

 of larvae (103 specimens) was obtained at the 

 equator. 



Lampadena spp. (38 occurrences, 119 specimens) 



Two and possibly three kinds of Lampadena 

 larvae were obtained on EASTROPAC. A de- 

 velopmental series definitely has been established 

 for only one species, Lampadena urophaos Pax- 

 ton. The relatively few occurrences of Lampa- 

 dena larvae on EASTROPAC I were mostly in 

 the southern portion of the three outer vessels 

 (24 of 38 occurrences) and most of the remain- 

 der in an offshore band lying between lat 4° and 

 8° N (9 occurrences). 



Lampanyctus spp. (376 occurrences, 5,882 larvae) 



Larvae of Lampanyctus were taken in more 

 collections than those of any other myctophid 

 genus but were not identified to species. A num- 

 ber of species of Lampanyctus occur in the 

 EASTROPAC area, of which L. idostigma Parr, 

 L. omostigma Gilbert, L. parvicatida (Parr), 

 and L. steinbecki Bolin are among the more 

 common. Larval series are being worked out 

 for these. 



Lepidophanes sp. (34 occurrences, 163 larvae) 



The species of Lepidophanes that occur in the 

 EASTROPAC area belong to the Lepidophanes 



27 



