398 
Fishery Bulletin 106(4) 
Table 1 
Summary of photographic data collected for cetaceans in the eastern tropical Pacific Ocean from 1977 through 2003, including 
the number of usable photographs (“photographs”), number of sightings (“sightings”), number of identifiable individual ceta- 
ceans (“individuals”), and number of identifiable individuals infested with Xenobalanus (“infested individuals”). * Denotes newly 
reported hosts of Xenobalanus that were determined from this study. 
Infested 
Species 
Common name 
Years 
Photographs 
Sightings 
Individuals 
individuals 
Balaenoptera edeni* 
Bryde’s whale 
2003 
415 
30 
43 
3 
Balaenoptera musculus 
blue whale 
2003 
513 
17 
24 
9 
Balaenoptera physalus 
fin whale 
2003 
92 
4 
6 
1 
Delphinus capensis* 
long-beaked common dolphin 
2003 
228 
13 
69 
2 
Delphinus delphis 
short-beaked common dolphin 
2003 
1146 
48 
287 
3 
Feresa attenuata 
pygmy killer whale 
2003 
25 
1 
11 
0 
Globicephala macrorhynchus 
short-finned pilot whale 
2003 
1551 
34 
297 
9 
Grampus griseus 
Risso’s dolphin 
2003 
155 
12 
58 
1 
Lagenodelphis hosei 
Fraser’s dolphin 
2003 
34 
1 
6 
0 
Lagenorhynchus obliquidens 
Pacific white-sided dolphin 
2003 
5 
1 
2 
0 
Lagenorhynchus obscurus 
dusky dolphin 
2003 
245 
11 
68 
4 
Megaptera novaeangliae* 
humpback whale 
2003 
504 
12 
34 
1 
Mesoplodon spp. 
unidentified Mesoplodon 
2003 
40 
2 
3 
0 
Orcinus orca 
killer whale 
1977-2003 
1160 
49 
354 
69 
Peponocephala electro 
melon-headed whale 
2003 
17 
1 
9 
0 
Physeter macrocephalus 
sperm whale 
2003 
215 
9 
19 
0 
Pseudorca crassidens 
false killer whale 
2003 
49 
2 
11 
0 
Stenella attenuata 
pantropical spotted dolphin 
2003 
1281 
76 
326 
4 
Stenella coeruleoalba 
striped dolphin 
2003 
845 
51 
319 
18 
Stenella longirostris* 
spinner dolphin 
2003 
770 
39 
271 
3 
Steno bredanensis 
rough-toothed dolphin 
2003 
118 
12 
41 
0 
Tursiops truncatus 
bottlenose dolphin 
2003 
600 
61 
252 
5 
Total 
10,008 
486 
2510 
132 
( Feresa attenuata ); Fraser’s dolphin ( Lagenodelphis 
hosei)\ Pacific white-sided dolphin ( Lagenorhynchus 
obliquidens ); melon-headed whale (Peponocephala elec- 
tro)', sperm whale ( Physeter macrocephalus ); false killer 
whale ( Pseudorca crassidens), rough-toothed dolphin 
( Steno bredanensis ); and three unidentified beaked whale 
individuals (Mesoplodon spp.) Of these, the barnacle has 
been previously reported throughout its worldwide range 
on pygmy killer whale, false killer whale, two species of 
beaked whales (Mesoplodon spp., Rajaguru and Shantha, 
1992), Pacific white-sided dolphin (Dailey and Walker, 
1978), and rough-toothed dolphin (Addink and Smeenk, 
2001 ). 
Four cetacean species seen in the ETP had not previ- 
ously been reported as hosts of Xenobalanus'. Bryde’s 
whale ( Balaenoptera edeni ), long-beaked common dol- 
phin ( Delphinus capensis), humpback whale (Megap- 
tera novaeangliae), and three forms of spinner dolphin 
( Stenella longirostris ): eastern (S. longirostris orienta- 
lis) and the forms known commonly as whitebelly and 
southwestern spinner dolphins (Table 2). For Bryde’s 
whales and humpback whales, the dorsal fin was the 
only visible appendage, as opposed to the long-beaked 
common dolphins and spinner dolphins for which pecto- 
ral flippers and tail flukes were also visible. The hump- 
back whale individual that displayed a single specimen 
of Xenobalanus appeared to have a damaged dorsal fin. 
Prevalence and intensity of the barnacle 
Blue whales (Balaenoptera musculus ) had the highest 
mean prevalence of the barnacle, followed by fin whales 
(B. physalus) and killer whales (Fig. 3A). There was a 
significant difference in mean prevalence among species 
(^! o _5o. 6, PcO.Ol) and Mysticetes had a higher mean 
prevalence of the barnacle than Odontocetes (5.1% vs. 
0.8%). Standard error was greatest for blue (13.8) and 
fin whales (16.5); all other species had a standard error 
less than 1.5. Blue, fin, and killer whales also had the 
highest prevalence per sighting, and 38% of killer whale 
sightings had barnacles (Fig. 3B). Prevalence per sight- 
ing was similar for Mysticetes and Odontocetes (12.7% 
vs. 14.0%) — a nonsignificant difference (P=0.19). Of the 
three species most often infested, killer whales repre- 
