HOBSON: FEEDING RELATIONSHIPS OF FISHES 



Figure 3. — Coral-rich habitat. Fishes shown include: Chaetodon multicinctus, Ctenochaetus strigosus, Zebrasoma 



flavescens, Acanthiirus nigrofuscus, and Zanclus canescens. 



the two forms o^Porites share dominance. Never- 

 theless, the fishes listed in Table 1,^ which are 

 characteristic of those seen in the coral-rich 

 habitat by day, were observed where P. pukoensis 

 was the more dominant coral. Table 2 ^ lists fishes 

 characteristic of those seen in this same habitat at- 

 night. Because of difficulties inherent in making 

 transect counts after dark, data in Table 2 are only 

 rough approximations; they are presented primar- 

 ily to illustrate the differing situation after dark, 

 and to emphasize that the other counts reflect a 

 situation characteristic of daytime only. 



^Table 1 is based on data from five transects at four coral-rich 

 sites — two at Honaunau, and two at Kaopapa in Kealakekua 

 Bay (see Figure 1 ). Total number of species observed on these five 

 transects: 82; mean number of individuals of all species for a 

 single transect: 522. 



^Table 2 is based on data from three nocturnal transects (one 

 on a dark night, two on moonlit nights) at three coral-rich 

 sites — two at Honaunau, one at Kaopapa in Kealakekua Bay 

 (see Figure 1), all three of which were also used in daytime 

 counts (Table 1). Counts were made by switching on a light 

 briefly about every 10 m as we swam along the line. Listing of a 

 species does not necessarily imply activity; as becomes clear in 

 the species accounts, below, some of these fishes are inactive on 

 or near the reef at night. Total number of species observed on 

 these three transects: 36; mean number of individuals of all 

 species for a single transect: 165. 



Boulder Habitat 



From shore to depths of about 15 m throughout 

 that part of the study area lying off exposed 

 shorelines, the sea floor is strewn with basalt 

 boulders. Often these boulders are dotted with 

 various algae and corals — mostly encrusting 

 varieties — but because these forms are small, the 



Table 1. — The 10 fish species most frequently seen along trans- 

 ect lines in the coral-rich habitat during the day. 



Mn making transect counts I tollowed Gosllne and Brock (1960) in 

 recognizing Chromis leucurus to Include two color forms. Furtfier study 

 may sfiow thiat two (or more) species are Included here (see species 

 account for C. leucurus in this report). 



919 



