FISHERY BULLETIN: VOL. 72, NO. 4 



more like these small individuals of A. 

 macuUferus than they do like the adults of their 

 own species, so this behavior may be characteris- 

 tic only of the smaller representatives of all three 

 species. 



Finally, a fourth apogonid, Pseudamiops 

 gracilicauda, is relatively numerous in Kona, but 

 does not seem to grow longer than about 30 mm. 

 Being such a small species, P. gracilicauda 

 generally went unnoticed by me and, in fact, was 

 seen only on dark nights when solitary individu- 

 als hovered 1 to 2 m above the reef. 



Suyehiro (1942), Hiatt and Strasburg (1960), 

 and Hobson (1965), all reported that certain 

 apogonids cease to feed sometime during repro- 

 ductive activity. Perhaps this phenomenon ac- 

 counts for the relatively high incidence of empty 

 stomachs at night in A. menesemus from Kona (15 

 of 40), especially considering that species of other 

 nocturnal groups with similar diets, like the vari- 

 ous holocentrids (see above), are almost always 

 full of food at night. 



E. H. Chave, University of Hawaii, is currently 

 working on the ecology of Hawaiian apogonids. 



Family Carangidae: jacks 



The jacks are prominent fishes on Hawaiian 

 reefs, but although many species were seen occa- 

 sionally during this study, only one, presented 

 below, was observed regularly. 



Caranx melampygits Cuvier — blue ulua, omihi 



This jack (Figure 21), attains a length of about 1 

 m in Hawaii (Gosline and Brock, 1960), but most 

 of those present in Kona during this study were 

 less than half this size. During the day it usually is 

 solitary, or in groups of several individuals. Typi- 

 cally, it swims actively about 1 m above the reef in 

 a manner that suggests it is patrolling over a 

 relatively large area. Frequently several of these 

 jacks accompany the large piscivorous goatfish, 

 Parupeneus chryserydros (see account for this 

 species, below), probably to capture prey that are 

 driven out of hiding as the goatfish probes the 

 substratum. This jack swims over the reef 

 throughout the day, but occurs there most fre- 

 quently during early morning and late afternoon 



Figure 21. — Caranx melampygus, a jack, swimming close above the reef during the day. 



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