FISHERY BULLETIN; VOL. 72, NO. 4 



Family Fistulariidae: cornetfishes 



Fistularia petimha Lacepede 



The cornetfish (see Hobson, 1968a: Figure 9) 

 looks much like the trumpetfish, but grows con- 

 siderably larger, many being over 1 m long. It is a 

 pale-green fish with light-blue markings, and 

 under certain circumstances instantaneously dis- 

 plays a series of broad bands along its body. Ear- 

 lier I (Hobson, 1968a) reported that this species in 

 the Gulf of California displays these bands when 

 poised to strike prey. In Kona, the bands appear in 

 similar circumstances and also in situations that 

 suggest the fish might feel threatened, as when 

 it is approached underwater by a human — 

 especially a human carrying a diving light at 

 night. Fistularia petimha frequently swims in 

 loosely spaced groups of several individuals, 

 generally in exposed shallowwater locations over 

 the reef top. 



Occasionally, F. petimha was seen in Kona 

 stalking its prey during daylight, as observed in 

 the Gulf of California (Hobson, 1968a). It does not 

 move suddenly until within a few centimeters 

 of its prey. When positioned for attack, it often 

 draws its midsection into a modified "s" (as 

 viewed from above), then darts forward for the 

 capture. Fistularia petimha is more agile than 

 A. chinensis, and undulating body movements 

 not seen in the latter are regularly used to provide 

 greater thrust in attacks and accelerated swim- 

 ming. In the Gulf of California, I saw F. petimha 

 use other fish as shields behind which to approach 

 prey, as described above for A. chinensis, but 

 did not see this in Kona. The behavior of F. petima 

 was not seen to differ between day and night. 



The 10 specimens (673: 363-1,069 mm), al- 

 though collected during both day and night, were 

 too few to provide much evidence on feeding times; 

 however, of the 2 with empty guts, 1 was collected 

 during late afternoon, and the other just before 

 first morning light, indicating that these 2 had not 

 fed during the preceding day and night, respec- 

 tively. Only two specimens contained fresh prey, 

 and both were collected shortly after twilight 

 — one after evening twilight, the other after morn- 

 ing twilight. Though limited, these data suggest 

 crepuscular feeding. Although prey in the other 

 six specimens were in stages of digestion not in- 

 consistent with predominantly crepuscular feed- 

 ing, they clearly showed that prey are also taken 

 at other times. All eight individuals with material 



in their stomachs had fed on fishes exclusively; 

 only two prey could be identified to species, one a 

 70-mm cardinalfish, Apogon snyderi, the other a 

 52-mm 6.a.mse\fish.,Ahudefdufimparipennis. Both 

 of these prey could have been captured close to reef 

 crevices during the day. 



Thus, F. petimha in Kona, as in the Gulf of 

 California (Hobson, 1968a), was found to prey only 

 on fishes. Hiatt and Strasburg ( 1960) also reported 

 this species in the Marshall Islands to be exclu- 

 sively piscivorous. My data suggest that F. 

 petimha takes somewhat smaller prey than does 

 A. chinensis of comparable length, as might be 

 expected in view of the deeper body and snout of 

 the latter. The mean length of the seven F. 

 petimha containing measurable prey was 593 mm 

 (range: 363-795 mm). The 11 measurable prey in 

 these individuals had a mean length of 32 mm 

 (range: 8-70). Comparable data for A. chinensis 

 are given above. 



CONCLUSION.— F/s^?//ar/a petimha stalks 

 fishes most successfully during twilight, but 

 also during the day and perhaps at night. 



General Remarks on Cornetfishes 



The exclusively piscivorous habits of Fistularia 

 petimha are paralleled by the similar diet of F. 

 tahacaria in the tropical Atlantic (Randall, 1967). 

 Suyehiro (1942) claimed that/^. petimha feeds on 

 tiny floating organisms by using its snout like a 

 pipette, but I join Hiatt and Strasburg (1960) and 

 Randall (1967) in contesting this opinion of the 

 size of its prey. Starck and Davis (1966) found F. 

 tahacaria to be more numerous on Florida reefs at 

 night than during the day, but did not speculate 

 that this reflected differences in feeding behavior. 



Order Scorpaeniformes 

 Family Scorpaenidae: scorpionfishes 



Pterois sphex Jordan and Evermann — 

 lionfish, nohu pinao 



The lionfish is a sluggish, solitary species that 

 usually rests motionless on the reef, yet draws 

 attention by its spectacular appearance (Figure 

 16). Perhaps because its fin spines carry a potent 

 toxin, this fish makes little effort to evade a 

 human collector. It is not numerous in Kona, and 



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