Pearlfishes from Guam— -SMITH 
39 
TABLE 3 
Seasonal Variation in Rates of Infestation 
OF TUMON Bay Stichopus chloronotus 
(All hosts were collected in the same part of the bay.) 
MONTH 
NUMBER OF 
Stichopus 
% WITH 
Carapus homei 
November I960 
24 
88 
December I960 
102 
84 
January 1961 
14 
71 
February 1961 
37 
76 
March 1961 
10 
80 
April 1961 
— 
— 
May 1961 
25 
16 
June 1961 
16 
31 
An individual removed from its host during 
daylight hours attempted to re-enter the slit and 
eviscerated body of the holothurian. It was easily 
captured by hand and made no effort to escape 
from my closed fist. The observations of pearl- 
fish out of the hosts at night did not seem to 
be related to any unusual conditions, and the 
scarcity of such observations is probably due to 
the limited time spent on the reefs at night. 
On one occasion I was told of an Encheliophis 
gracilis observed entering an unidentified sea 
cucumber about three o’clock in the afternoon. 
The host was opened and the fish was recovered. 
LIFE HISTORY 
Arnold (1956) has summarized the life his- 
tory of Carapus acus and the observations re- 
corded here only serve to indicate that the life 
history of C. homei is generally similar. Tenuis 
larvae of homei were found in Stichopus chloro- 
notus from October to February, and posttenuis 
stages were collected until May. None of the 
TABLE 4 
Variation in Infestation Rate by Locality 
LOCALITY 
DATE 
NO. 
Stichopus 
chloronotus 
% WITH 
Carapus 
homei 
Turnon Bay 
Nov.-June 
228 
av. 63 
Piti 
Mar. 18 
22 
0 
Asan 
Feb. 28 
89 
9 
Merizo 
Jan. 28 
29 
14 
Togcha 
Dec. 23 
5 
av. 46 
May 14 
8 
homei taken during this study (October to July) 
had maturing gonads, indicating that spawning 
takes place during the summer months as in 
the case of C. acus. 
Transformation from the tenuis to the adult 
form is accompanied by a considerable reduction 
in total length. The longest tenuis was 197 mm, 
the shortest adult 69 mm, suggesting that they 
may lose as much as 65% of their length during 
transformation. Figure 5 shows the changes in 
head length-body length ratio accompanying 
the transformation from tenuis to adult. 
Two female Encheliophis gracilis with nearly 
ripe ovaries were collected February 23 and 
May 26. The February specimen, 217 mm long, 
had a single developed ovary 16 X 11 X 6.5 
mm. A rough count places the number of 
oocytes of the largest class at approximately 
14,000. Several other size classes are distin- 
guishable. The May specimen is 186 mm long, 
its ovary is 1 1.6 X 7. 5 X 3.6 mm. In view of the 
structural distinctness of Encheliophis it is un- 
fortunate that its life history remains unknown. 
FOOD HABITS 
Stomachs of 185 pearlfishes were examined 
with the following results: 
Encheliophis gracilis 1 1 examined 
empty 6 
holothurian viscera 4 
unidentified remains 1 
Carapus parvipinnis 1 examined 
empty 1 
Carapus mourlani 5 examined 
empty 5 
Carapus homei 168 examined 
empty 127 (75.6%) 
C. homei tenuis 19 ( 11.3% ) 
shrimp 12 ( 7.2%) 
unidentified fish 5 ( 3.0%) 
C. homei adult 1 ( .6%) 
shrimp and fish .. 2 ( 1.2%) 
unidentified remains 2 ( 1.2%) 
The stomachs of Encheliophis gracilis that 
contained what appeared to be holothurian vis- 
cera were very full and considerably distended. 
This threadlike material has been identified 
from histological sections as testis tissue. Stras- 
