AHLSTROM: KIND AND ABUNDANCE OF FISH LARVAE 



to 13°S along long 88°W, and three additional 

 records were obtained at MARCHILE VI sta- 

 tions (not included in above totals). At least 

 two species, L. gemellari (Cocco) and L. dumer- 

 ili (Bleeker), and perhaps a third, are involved. 



Loweina laurae (Wisner) 

 (25 occurrences, 37 larvae) 



Wisner (1971) has separated the eastern Pa- 

 cific species of Loweina from L. vara (Liitken). 

 Although the two species are basically quite sim- 

 ilar, Wisner points out that L. laurae has a 

 somewhat longer head, 27.3 to 30.7% of SL 

 versus about 25.7%, and a somewhat larger eye, 

 averaging about 8% of SL versus about 6%. 

 Wisner gave the distribution of L. laurae in the 

 eastern Pacific as between lat 30 °N and 30 °S 

 and westerly to long 150°W. 



Of the 25 occurrences of larvae of L. laurae 

 on ETP II, all but one occurred in a broad equa- 

 torial band between lat 7°N and 6°S (Figure 

 14). The isolated record was on the southern- 

 most line of stations oriented normal to the coast 

 occupied by Rockaway. This distribution is sim- 

 ilar to that illustrated for ETP I (Moser and 

 Ahlstrom, 1970, Figure 51). In equivalent cov- 

 erage on ETP I, 31 stations yielded 41 larvae. 

 It should be noted that larvae of Loweina from 

 EASTROPAC appear to be identical with those 

 identified as L. rara from other oceans; hence 

 larval evidence does not support the separation 

 of the eastern Pacific form as a separate spe- 

 cies. 



Myctophum spp. 



(217 occurrences, 2,185 larvae) 



Larvae of the genus Myctophtim ranked 

 fourth in abundance and third in frequency of 

 occurrence. Larvae of M. aurolaternatum Gar- 

 man (148 occurrences, 674 larvae) were taken 

 more frequently but in lesser amounts than lar- 

 vae of M. nitidulum-complex (134 occurrences, 

 1,291 larvae). Larvae of M. aurolaternatum 

 were taken in all parts of the EASTROPAC pat- 

 tern, but in largest numbers between the equator 



and lat 5°N. Most larvae of M. nitidulum-com- 

 plex were taken in a broad equatorial band be- 

 tween lat 8°N and 5°S (Figure 11). The dis- 

 tribution, however, had a southerly extension 

 to the bottom of the pattern in the area of the 

 Humboldt Current. Larvae of M. asperum 

 Richardson (26 occurrences, 180 larvae) were 

 taken in an offshore equatorial tongue, extending 

 seaward from long 98 °W to its widest extent 

 (lat 2°S to 7°N) along long 119°W (Figure 3). 

 The remainder of Myctophum larvae (17 occur- 

 rences, 40 larvae) belong to two and possibly 

 three species. One group of these occurred in 

 the offshore equatorial tongue, along with larvae 

 of M. asperum; the other group occurred be- 

 tween lat 7° and 10 °S in the offshore Washington 

 pattern. The latter group includes larvae of 

 both M. lychyiohium Bolin and M. brachygnathos 

 (Bleeker). 



Only larvae of M. aurolaternatum were sep- 

 arately tabulated for equivalent ETP I coverage 

 (145 occurrences, 529 larvae). Both the dis- 

 tribution of M. aurolaternatum larvae and their 

 frequency of occurrence were similar for the two 

 multivessel surveys, although abundance was 

 moderately greater on ETP II, 1.9 versus 1.5 

 larvae per haul. This pattern of greater abun- 

 dance on ETP II also held for the remainder of 

 the larvae of Myctophum, 4.3 versus 2.9 larvae 

 per haul. 



Notolychnus valdivtae (Brauer) 

 (100 occurrences, 534 larvae) 



Larvae of the wide-ranging oceanic species 

 are seldom taken closer to shore than 200 miles. 

 On ETP II, the majority of records were from 

 an equatorial tongue that extended between lat 

 10°S and 10°N in the oflFshore Washington pat- 

 tern, but shoreward of this (long 105° to 85°W) 

 the distribution narrowed to between lat 2°S and 

 8°N, with the majority of occurrences between 

 lat 2° and 6°N. A second group of larvae were 

 sampled in the southern portion of the Rockaway 

 pattern between lat 9° and 15°S. Only two oc- 

 currences of Notolychnus larvae were noted in 

 85 stations occupied by all vessels between lat 

 20° and 10°N. Distribution of Notolychnus 



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