FISHERY BULLETIN: VOL. 72, NO. 4 



Hawaii migrates offshore at night. In Florida, 

 however, Starck and Davis (1966) noted only that 

 it is active at night in the same areas where it is 

 sheltered in daylight; they illustrated this species 

 with a mottled color pattern, which they believed 

 to be its nocturnal coloration. The same mottled 

 pattern occurs regularly at night in Kona when 

 the fish is held in the beam of a diving light, and I 

 believe it is a response to the light, rather than a 

 nocturnal coloration — especially because the pat- 

 tern is intensified upon moving the light progres- 

 sively closer to the fish. In the absence of a diving 

 light at night, this species is either plain red (as it 

 usually is in daylight), or, more often with indi- 

 viduals in mid-water, overall pale-silver (occa- 

 sionally this pale-silver coloration is displayed 

 under cover during the day). The blotched pattern 

 is the red and silver hues in combination. 



CONCLUSION. — Priacanthus cruentatus is a 

 nocturnal predator that feeds on free-swimming 

 organisms, mostly crustaceans and cephalopods. 



Family Apogonidae: cardinalfishes 



Apogon erythrinus Snyder 



After dark, this small solitary cardinalfish is 

 numerous close to basalt reefs in water less than 6 

 m deep, usually in small sand and cobble pockets. 

 The smaller ones are largely transparent, and 

 transparency remains a characteristic of even the 

 largest individuals, despite an increased pinkish 

 hue (Figure 19). During the day A. erythrinus 

 remains out of sight, secreted deep in reef crevices. 



Of 14 individuals (36: 22-42 mm) examined, 4 

 that had been collected together from a deep crev- 

 ice 4 h after sunrise were empty (rotenone was 

 used to collect these 4, a departure from the stan- 

 dard collecting method necessary here because the 

 species was never visible during the day). The 

 other 10 specimens were speared from among 

 those active in exposed locations on the reef at 

 night (more than 4 h after sunset), and although 2 

 were empty, the other 8 contained prey in their 

 stomachs. 



All eight with material in their stomachs con- 

 tained crustaceans exclusively. Xanthid crabs 



Figure l9.~Apogon erythrinus, a cardinalfish, showing the transparency t5T)ical of this species as it swims close to 



the reef at night. 



950 



