Postlarval Scombroid Fishes of the Genera Acanthocybium^ Nealotus f and 
Diplospinus from the Central Pacific Ocean 
Donald W. Strasburg 1 
Exclusive of the mackerels and tunas, whose 
commercial importance has caused them to be 
studied extensively, the early life history of 
scombroid fishes is poorly known. This is par- 
ticularly true of the families Gempylidae and 
Trichiuridae, even though they are the bases for 
fisheries in Australia, South Africa, Madeira, and 
parts of Asia. There is also a paucity of life- 
history information about the non-schooling 
Scombridae. This paper describes young stages of 
the scombroid Acanthocybium solandri (Cuvier 
and Valenciennes), the gempylid Nealotus tripes 
Johnson, and the trichiurid Diplospinus mul- 
tistriatus Maul, all three belonging to monotypic 
genera. The first has a slight commercial im- 
portance (Iversen and Yoshida, 1957:370), the 
others may be considered rare species of no 
commercial value. 
The three families are taxonomically well 
known, the Scombridae having been reviewed 
by Fraser-Brunner (1950), the Gempylidae by 
Matsubara and Iwai (1952) and Grey (1953), 
and the Trichiuridae by Tucker (1956). All of 
these authors dealt essentially with adult fish. 
Postlarval Acanthocybium are hitherto unre- 
corded, the smallest specimen mentioned in the 
literature measuring 27 cm (Kishinouye, 1923: 
387). Similarly, the smallest Diplospinus is 125 
mm (Maul, 1948:45), although there is a pos- 
sibility that a 69 mm Lepidopus may in reality 
be a Diplospinus (Tucker, 1956:81). Small Nea- 
lotus have been recorded by Liitken (1880:458), 
Gunther ( 1887: 35 ), Norman ( 1930:351 ), and 
Voss ( 1957:304). Liitken figured his specimens 
but regarded their identity as dubious. His larger 
specimen ( about 13 mm standard length) has 
20 spines in the first dorsal and is probably 
1 Bureau of Commercial Fisheries Biological Lab- 
oratory, Honolulu, Hawaii. Manuscript received No- 
vember 13, 1962. 
Nealotus. His smaller fish measures only about 
8 mm in standard length and cannot be identi- 
fied with certainty. 
All material reported upon here was collected 
by "British Columbia” trawl during cruise 47 
of the Bureau of Commercial Fisheries research 
vessel "Hugh M. Smith.” This cruise took place 
in October— November 1958, in the central Pa- 
cific southeast of Hawaii. A description of the 
collection method is included in Matsumoto’s 
report (in press) on the young tunas taken on 
this cruise. Figure 1 locates the trawling stations 
and capture sites of the species under considera- 
tion. Additional data may be found in Table 1 
and in the species diagnoses. 
Following capture, the fish were preserved in 
formalin and subsequently transferred to 65% 
ethyl alcohol. This particular concentration 
produced less wrinkling, hardening, and dis- 
tortion than the customarily used 70% solution. 
Most specimens were stained with alizarin, but 
clearing the tissues, as with glycerin, was not 
done. 
Thanks are due Messrs. G. Palmer, N. B. 
Marshall (British Museum), and G. E. Maul 
(Museu Municipal do Funchal) for supple- 
mentary information on Diplospinus , and Mrs. 
Nancy A. Voss (University of Miami Marine 
Laboratory) for data on Nealotus . The Inter- 
American Tropical Tuna Commission (La Jolla, 
California) loaned young Scomberomoms. I am 
also indebted to Tamotsu Nakata, Bureau of 
Commercial Fisheries Biological Laboratory, Ho- 
nolulu, for preparing the figures. 
Acanthocybium solandri (Cuvier and 
Valenciennes) 
Station 60 1 specimen: 23.7 mm 
The single Acanthocybium captured is rather 
easily recognizable in spite of the fact that its 
174 
