FISHERY BULLETIN: VOL 



adult or semiadult Nanwhthya — the upper beak 

 notably shorter than the lower. We have examined 

 most, if not all, of these specimens and found them 

 to be referable to Nanichthys. Also, most of the 

 reports of Scorn beresox saurus from the South At- 

 lantic and Indian Oceans by Lampe ( 1914) ("L" in 

 Figure 12) may, on the basis of geographical evi- 

 dence, be referable to Nanichthys. We have, how- 

 ever, not seen the specimens, but many of Lampe's 

 collections occurred in the area of overlap (Figure 

 16). Dudnik ( 1975a) reported on an extensive col- 

 lection of "Scomheresox saurus" from the South 

 Atlantic (about .3,000 specimens, from 8 to 460 

 cm). In general his data agree well with ours and 

 with Parin's (1968a, b) but he shows (Dudnik 

 1975a, fig. 2) the species to extend northward to 

 about 18° S along the coast of Africa. This is nota- 

 bly farther north of the expected range but is well 

 within that o( Nanichthys. He did not discuss the 

 dwarf {"Scomberesox sp") in his study (Dudnik 

 1975a), submitted for publication on 20 January 

 1974, nor did he compai'e it with its larger relative, 

 although presumably he was aware of the form 

 and of Parin's 1 1968a) study for he submitted his 

 own (Dudnik 1975b) concerning it on 20 Novem- 

 ber 1974. As no tabular or descriptive morphologi- 

 cal data were offered in the first study (on Scom- 

 beresox saurus), it is not entirely clear whether or 

 not Dudnik 1 1975a) dealt only with the larger 

 form, for he indicated that only smaller specimens, 

 larvae to juveniles up to 100 mm (a size range 

 encompassing most adults of Nanichthys), occur- 

 red north of 20° S. Also, in his later work on Scom- 

 beresox sp. (= Nanichthys simulans), Dudnik 

 (1975b) showed collections of the dwarfed form 

 between about 10 and 15 S in this same area off 

 Africa. 



The dwarfed form, Elassichthys adocetus, of the 

 eastern Pacific Ocean also has been confused with 

 the young of Cololabis .sa;ra. Roedel (1953) and 

 Chirichigno F. ( 1962) reported C. saira (as young) 

 from off northern Peru. Schaefer and Reintjes 

 ( 1950) reported (as young of C. saira ) specimens of 

 E. adocetus from between the Hawaiian Islands 

 and the western coast of North America. 



Elassichthys adocetus appears to be less anti- 

 tropically distributed than is Nanichthys simu- 

 lans in the Atlantic Ocean. A few specimens have 

 been taken between the two principal areas of 

 occurrence north and south of the Equator ( Figure 

 13); perhaps these are strays from the main groups 

 (presumably from the southern) and transported 

 there by the complex current systems of the area 



and/ or associated with oceanic fronts, as reported 

 by Knauss ( 1957) in the vicinity of 03° N, 120° W. 



An interesting aspect of the distributions of the 

 northern population of £. adocetus is its absence 

 from the large area bounded by about 1 15° W and 

 the Equator. Also, it has not been taken within 

 hundreds of miles of the coast of Baja California, 

 Mexico. In contrast, the species is very common in 

 the coastal waters of Ecuador and Peru. One 

 reason for the avoidance (or absence) of the area 

 westerly of Baja California may be the still cool 

 water of the California Current, between 18° and 

 25° N. This broad current is evident out to about 

 120° W and flows southerly to about 22 N between 

 January and June-July before turning westerly 

 and mixing with the North Equatorial Current; 

 from August to December these two currents 

 merge at or north of 20° N. Temperatures within 

 this large area range between 25 and 29° C 

 (Wyrtki 1964) and are probably above the op- 

 timum tolerated by the species. Also, this area is 

 one of very low oxygen content (0.05 ml/1), but this 

 may not be a factor in the distribution of E. adoce- 

 tus as it is an entirely surface form and probably 

 remains well above the upper depth limit of the O^ 

 minimum layer, between 50 and 200 m (Wyrtki 

 1967). 



The occurrence of £. adocetus (and S. saurus 

 scombroides ) near the coasts of Ecuador and Peru, 

 and its westward extension of range to about 1 15 

 W near the Equator, are no doubt due to the still 

 cool water of the Peru Current; the temperatures 

 range to about 20-26° C in summer and 16 -24 C 

 in winter, between about 0° and 22 S (Wyrtki 

 1964). 



In the northeastern Pacific Ocean the ranges of 

 C. saira (again mostly juveniles and young) and 

 the northern population of £. adocetus overlap in 

 an extensive area roughly bounded by about 20 to 

 30' N, 115° to 155° W (Figure 17); perhaps the 

 overlap is primarily seasonal but often the two 

 have been taken together in the northern portion 

 of the overlap area. King and Iversen ( 1962:320, 

 app. table 8) reported one specimen (86 mm) of 

 "Scomberesocidae" from the Equatorial Counter 

 Current (ECC) in 1955-56. No coordinates were 

 given but the collection was made between about 

 108° and 160° W within the ECC. the boundaries of 

 which these authors indicated to be between about 

 5° and 10° N (p. 286, fig. 12). The stated size ("86 

 mm") is notably longer than the largest of hun- 

 dreds examined by us (about 68 mm SL). but it can 

 scarce! V be other than Elassichthvs, which is 



558 



