AHLSTROM: FISH LARVAE IN EASTERN TROPICAL PACIFIC 



was known from a single collection made off 

 Hawaii (Grey, 1961). Adults and larvae were 

 described by Ahlstrom and Moser (1969). 



Cyclothone spp. (301 occurrences, 2,181 larvae) 



Larvae of Cyclothone spp. were taken least 

 frequently in the northern quarter of the EAS- 

 TROPAC pattern (betweeen lat 10° and 20° N, 

 and in the inner pattern occupied by Alaminos 

 (Table 11 and Fig. 5). In the former area, 

 less than 20 Sf of the hauls (20 of 103) con- 

 tained Cyclothone larvae; in the inshore pat- 

 tern only about 45 % of the hauls (47 of 103) 

 contained Cyclothone larvae. Over the remain- 

 der of the EASTROPAC I pattern Cyclothone 

 larvae occurred at most stations (234 of 276). 

 The lowest number of larvae per positive haul, 

 2.15 larvae, was obtained in the northern sec- 

 tion; the next lowest, 3.55 larvae per positive 

 haul, in the Alaminos pattern. Over the re- 

 mainder of the pattern, 8.42 larvae were ob- 

 tained per positive haul. 



No attempt was made to identify the larvae 

 of Cyclothone to species, and our hauls did not 

 extend deep enough to collect adults. 



Diplophos taenia Giinther (73 occurrences, 183 

 larvae ) 



A study was made of larval and adult speci- 

 mens of Diplophos in an attempt to determine 

 whether the Pacific specimens should be as- 

 signed to D. taenia or retained as a distinct 

 species, D. pacificus Giinther. Grey (1960) had 

 placed Pacific specimens in D. taenia but later 

 she (Grey, 1964, p. 89) developed reservations 



because of the consistently lower photophore 

 count of the ventral series in Pacific specimens. 

 Without detailing my observations on Diplophos, 

 which I plan to publish separately, I have con- 

 cluded that our eastern Pacific Diplophos is not 

 separable from the Atlantic D. taenia. 



Larvae of Diplophos were taken most com- 

 monly to the north of lat 10° N — 36 occurrences, 

 105 larvae (Fig. 4). The remaining 37 occur- 

 rences, 78 larvae were distributed throughout 

 the EASTROPAC I pattern. 



Ichthyococcus spp. (41 occurrences, 61 larvae) 



Two kinds of Ichthyococcus larvae were taken 

 on EASTROPAC L The specific identity of 

 the more common form has been determined as 

 /. irregularis Rechnitzer and Bohlke; the other 

 form has yet to be identified to species. 



Maurolicus muelleri (Gmelin) (43 occurrences, 

 264 larvae ) 



Larvae of this species were taken only on an 

 equatorial band between lat 5° N and 5° S and 

 were not taken in the outer pattern occupied 

 by Argo (Fig. 4). This distribution, without 

 additional information, could be misleading. 

 Maurolicus is known to have a wide latitudinal 

 distribution in the South Pacific. For example, 

 Maurolicus larvae were obtained at lat 33° S 

 on MARCHILE VL the portion of EASTRO- 

 PAC II occupied by the Chilean vessel Yelcho. 

 We also have collections from south of New 

 Zealand, obtained on an Eltanin cruise. The 

 species may be carried northward oflF South 

 America in the Humboldt Current and then off- 

 shore in the equatorial current system. 



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