HOBSON: FEEDING RELATIONSHIPS OF FISHES 



phthirophagus, my observations of cleaning were 

 mostly incidental. Nevertheless, it was evident 

 that cleaning by T. duperrey is mostly an activity 

 of juveniles. Adults clean only infrequently, and 

 not at well-defined cleaning stations. 



To indicate the food of the post juveniles of this 

 species, 24 specimens, 125 (103-146) mm long, 

 were speared during the day as they swam ac- 

 tively over the reef. All contained identifiable 

 items, as listed in Table 52. In contrast with the 

 diet of most fishes examined during this study, no 

 single item or certain few items predominate in 

 the diet of T. duperrey, a circumstance that un- 

 doubtedly relates to its populating a wide range of 

 habitats. 



All 14 specimens (132: 60-200 mm) speared as 

 they swam on the reef during daylight contained 

 identifiable food material, as listed in Table 53. 

 Hiatt and Strasburg (1960) reported on two 

 specimens of this species (as T. umhrostigma) in 

 the Marshall Islands: one had consumed a 

 stomatopod, the other a fish. Randall (1955) re- 

 ported (also as T. umbrostigma) that one speci- 

 men taken in the Gilbert Islands contained a crab. 



CONCLUSION. — Thalassoma fuscus is a diur- 

 nal predator that feeds mostly on crabs and mol- 

 lusks. 



Halichoeres ornatissimus (Garrett) — /o'o 



CONCLUSION. — Thalassoma duperrey is a 

 diurnal predator that feeds on a very wide range of 

 shelled organisms, most of them benthic. 



Thalassoma fuscus (Lacepede) — hou 



This species was shown by numerous observa- 

 tions of spawning aggregations to include the 

 nominal T. umbrostigma (which represents the 

 juveniles and females). It is a fish of shallow water 

 along rocky, surge-swept shores and is one of the 

 most numerous species on the shallow reef flats. 

 Generally it does not occur in water deeper than 

 about 5 m and is strictly a diurnal fish that shel- 

 ters in reef crevices after dark. 



In Kona this labrid is nowhere particularly 

 numerous, yet it occurs regularly in all inshore 

 habitats. It is generally solitary and swims close to 

 cover during the day. At night it is out of sight, 

 presumably resting in crevices or under the sand. 



All 13 specimens (96: 76-115 mm), speared 

 during daylight, had a full gut that included fresh 

 material, as listed in Table 54. Food items more 

 than about 4 mm in greatest dimension were 

 crushed, and this included most of the mollusks. 

 Probably at least much of the unidentified mate- 

 rial constituted fragmented molluscan soft parts. 

 This fish plucks small benthic organisms off the 

 substratum, including some forms, like the di- 

 demnid tunicates, that are attached to the reef. 



Table 52. — Food of^ Thalassoma duperrey. 



991 



