FISHERY BULLETIN: VOL. 70, NO. 4 



Table 16. — Comparison of occurrence and average 

 abundance per haul of larvae of 10 families with highest 

 relative abundance on Oceanographer zig-transect with 

 equivalent coverage on ETP II. 



tions on ETP II, 5 versus 2 (Table 16), but one 

 of the two positive hauls at Oceanographer sta- 

 tions contained 353 larvae. This is considered a 

 chance collection of a patch of larvae. Larvae 

 of Bregmacerotidae were taken in only one 

 Oceanographer collection, compared to nine on 

 ETP II. Larvae of two species of Bregmaceros 

 were represented in ETP II stations but only- 

 larvae of B. bathymaster were taken in large 

 numbers. The single Oceanographer collection 

 of 470 larvae of this species was made at the 

 inner station off Mexico; two large collections 

 of B. bathymaster larvae were made at the two 

 inner stations off Mexico on ETP II (511 and 

 927 larvae). The principal difference in abun- 

 dance of Bregmaceros larvae between the two 

 coverages appears to be the chance collection 

 of two patches versus one patch of B. bathy- 

 master larvae. 



I have gone into some detail in order to point 

 up the influence of one or a few larger collections 

 of larvae on the estimates of relative abun- 

 dance (average number of larvae per haul) of 

 several of the more abundant kinds of larvae 

 in the zig-transect. Larvae of most kinds of 

 fishes are patchily distributed, rather than ran- 

 domly distributed. Variability associated with 

 patchiness in distribution of larvae may be 

 greater than variability due to temporal changes 

 in reproductive activity. In this comparison, 

 an example of temporal differences in repro- 

 ductive activity is afforded by the sardine. The 

 exceptionally large collection of thread herring 



larvae is certainly indicative of very heavy 

 spawning off Mexico in late November; the 

 single larva taken in the same area on ETP II 

 (September 15) may actually be indicative of 

 low reproductive activity or, contrariwise, may 

 simply reflect the circumstance that most hauls 

 of patchily distributed species contain few or 

 no larvae. Striking examples of the influence 

 of one or a few collections on the estimates of 

 abundance of larvae in the two coverages of the 

 zig-transect are afforded by larvae of the two 

 most common species, Vinciguerria lucetia (one 

 collection) and Diogenichthys late7'natus (two 

 collections) . I interpret difference in abundance 

 of both species in the two time periods involved 

 to be due primarily to variability associated with 

 patchy distribution of larvae rather than to tem- 

 poral differences in reproductive activity. 



COMMENTS ON LARVAE OF THE 



MAJOR FISH FAMILIES 



COLLECTED ON EASTROPAC II 



As mentioned in an earlier section, the kinds 

 of larvae obtained on the second multivesseJ 

 EASTROPAC cruise are summarized in Table 

 8 by family or larger grouping and by research 

 vessel. This table contains 59 categories: 53 

 families and 6 composite categories including 3 

 orders or suborders and those labelled "other 

 identified," "unidentified larvae," and "disinte- 

 grated larvae." Only those categories preceded 

 by an asterisk are commented upon in the text 

 discussion that follows; these include 31 fami- 

 lies and 4 composite categories. Each category 

 retains the sequential number given to it in this 

 table. 



The number of families included in the four 

 composite categories are as follows: other 

 Stomiatoidei (2), Anguilliformes (7), Lophii- 

 formes (10), and "other identified" (10). Hence 

 a total of 82 families were identified from ETP 

 II collections. 



Basic data on the kinds and numbers of fish 

 larvae obtained in the 355 ETP II stations are 

 contained in Appendix Tables 1-6, and station 

 data including location, date and time of collec- 

 tion, depth of haul, and standardized haul factors 

 for these stations are given in Appendix Table 8. 



1172 



