AHLSTROM: KIND AND ABUNDANCE OF FISH LARVAE 



high in ETP I as in ETP II, 43 positive hauls 

 as compared with 47, the average number of 

 larvae per positive haul was much higher on 

 ETP II— 16.4 larvae versus 6.1 larvae. 



Vinciguerria spp. 



(341 occurrences, 22,198 larvae) 



As in ETP I, larvae of Vinciguerria spp. 

 ranked second in overall abundance, exceeded 

 only by larvae of the myctophid, Diogenichthys 

 laternatus (Garman). They were obtained 

 throughout the EASTROPAC pattern, occur- 

 ring in 96 Cf of the collections (Figure 7). Av- 

 erage abundance of larvae per haul was about 

 one-third greater than in ETP I: 62.5 versus 

 47.2 larvae. 



Larvae of two species of Vinciguerria occur 

 within the ETP II pattern, although most were 

 those of V. lucetia Garman. As commented 

 upon for ETP I, larvae of V. nimbaria (Jordan 

 and Williamson) were taken principally in the 

 South Pacific central water mass, to the south 

 of about lat 5°S. On ETP II this distribution 

 involves about 20 collections only. 



Yarrella argenteola (Garman) 

 (18 occurrences, 33 larvae) 



Larvae of Y. argenteola were taken in a lim- 

 ited area shoreward or immediately south of the 

 Galapagos Islands between lat 2°N and 5°S 

 (Figure 6). No metamorphosing specimens 

 were observed, although larvae as large as 16 mm 

 were represented in the collections. As noted 

 in the introductory section, only one specimen 

 of Yarrella was obtained on ETP I, in contrast 

 to the 18 occurrences on ETP II. Adults of this 

 species were recorded from within the area cov- 

 ered on ETP II by Morrow (1957b), Grey 

 (1960), Bussing (1965), and Parin (1971). 



7. STERNOPTYCHIDAE 

 (277 occurrences, 7,385 larvae) 



As in ETP I, hatchetfish larvae ranked third 

 in abundance. Although hatchetfish larvae con- 



tributed almost identical percentages of the total 

 larvae in ETP II as in comparable ETP I (5.99% 

 versus 5.989r), the average number of larvae 

 per haul, 20.8 versus 13.9, reflected the greater 

 relative abundance of larvae on ETP II. As 

 noted for ETP I, hatchetfish larvae are more 

 fragile than most kinds, and a portion of the 

 larvae are too damaged to identify, except to 

 family. Even so, identification to genus was 

 made for most ETP II collections, and in these, 

 larvae of Sternoptyx sp. contributed about 85% 

 of the total and larvae of Argyropelecus (mostly 

 A. lychnus Garman), the remainder. Baird 

 (1971) in his revision of the family Sternop- 

 tychidae recognized three species of Sternoptyx, 

 with S. obscura Garman the common species in 

 the eastern tropical Pacific; however, he includ- 

 ed one record of S. diaphana Hermann from 

 within the area surveyed on ETP II. 



8. ASTRONESTHIDAE 

 (42 occurrences, 74 larvae) 



Astronesthid larvae were taken in about four 

 times as many collections as on equivalent ETP I. 

 Most larvae had an equatorial distribution be- 

 tween lat 8°N and 5°S; only two larvae occurred 

 elsewhere (Figure 5). Three distinctive kinds 

 of astronesthid larvae were taken. 



9. CHAULIODONTIDAE 



(56 occurrences, 207 larvae) 



Although larvae of ChauUodus sp. were taken 

 in a comparable number of hauls on ETP II and 

 ETP I (56 versus 59 occurrences), more larvae 

 were obtained on ETP II (207 versus 134 lar- 

 vae). The majority of ChauUodus larvae on 

 ETP II were taken in the inner half of the ETP 

 pattern, below the equator — 34 collections con- 

 taining 165 specimens were obtained from this 

 quadrant (Figure 8) . In other parts of the ETP 

 pattern somewhat fewer larvae were taken than 

 on ETP I. As on ETP I, the majority of pos- 

 itive hauls contained 1 to 3 larvae (41 of 56 

 hauls) ; even so, a higher proportion of the 

 hauls on ETP II contained somewhat larger 

 numbers of ChauUodus larvae, i.e., 6 to 26 lar- 

 vae per haul. 



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